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Learn About What Type of Motor Oil Should Be Used in Lawn & Garden Engines, and High Performance Engines	Detailed Information About the KT-series and Magnum Twin Cylinder Engines
How to Adjust/Set the Governor to Set the Top Speed RPM on a Kohler or Virtually Any Small Engine	Rare, Vintage Kohler K-series engine models KV161, L160/L161 and L181
How to Limit the Top Speed RPM and Safely Operate Virtually Any 4-Stroke Small Engine Without a Working Governor	How to Create a Hybrid Kohler Engine Model K261, K271, K281, K321, K371, K381 or K411
Exhaust Header Pipes For Sale, Information about Exhaust Header Pipes, and How to Remove a Broken-Off Exhaust Mounting Bolt or Stud and/or Rusted-In Exhaust Pipe Fitting	How to Convert a Single Cylinder Kohler K-Series Engine into a Magnum Engine
How to Calculate the Horsepower of a Small Engine and Determine Its Model Number	Professional Valve Seat and Guide Repair Service for Kohler Engine Model K361 Cylinder Head
How to Calculate the Correct Piston Compression Height	Professional and Precision Machine Shop Fabricating and Repair Services
Remote Stranded Wire Cable-Operated Spring-Return Foot/Gas Pedal Throttle Control Setup Kits	How to Reinforce OEM OHV V-Twin Aluminum Block Engines to Prevent from Cracking or Breaking for High Performance/Open RPM Competition Pulling
Desktop Dyno 2_0g | Desktop Dyno 2000 (Safe to download and use.)	Use an Auxiliary Crankcase Breather System to Prevent Oil Spillage at Open RPM

Available Soon - Detailed Illustrated Plans on How to Construct a Professional Pull-Back and Self-Propelled Garden Tractor/Small Wheel Mini Rod Pulling Sleds (Weight Transfer Machines)

Decoding Kohler K-series and Magnum Engine Model, Specification and Serial Identification Numbers -

The Kohler K-series and Magnum engine model and serial numbers appear on an adhered riveted aluminum plate or metallic vinyl label that's affixed to the flywheel shroud. If there's no plate or label on the shroud, if the printed ink lettering and numbers on the plate or label is faded away, or if the shroud was replaced with one from another engine, then there's no way of knowing exactly which specific parts the engine requires or the year the engine was manufactured. If the plate or label have legible wording and numbers, all you'll know is the model, specification and year of the flywheel shroud itself. Because flywheel shrouds can be swapped from one engine to another and unlike most automotive engines with identification numbers stamped directly on the block, there are no identification numbers on Kohler engine blocks themselves. Only an experienced and knowledgeable Kohler K-series or Magnum engine mechanic will know exactly which specific parts the engine requires. Certain Kohler K-series engines have the model number embossed on the Power Take Off (PTO) end of the block, but this is rare. Therefore, if the flywheel shroud is missing or if it's mismatched with the correct engine, the only true way finding for sure the size and model is to remove the cylinder head and measure the bore and stroke. Otherwise, they're like the early small and big block Chevy V8's, and the Chevy 348 and 409 "W" engines , there's no way of knowing for sure simply by looking at it from the outside. Because a Kohler K241 or M10 engine block can be bored and stroked to a model K301, M12, using the K301 or M12 piston, rod and crankshaft, and a K301 or M12 block can be bored to a model K321 or M14 using the K321 or M14 piston, rod and crankshaft. But the models K341 or M16 blocks are in a class by themselves. A K321 or M14 block could be bored for the K341 or M16 piston, but doing this would make the cylinder wall about 1/8" thick, or the boring process could break through the cylinder wall without centering the boring bar according to the outside of the cylinder beforehand. Therefore, this is NOT recommended.

Bore, Stroke and Valve Sizes of Kohler K-series and Magnum engines:

Engine Model

K90/K91

K141 (early)

K141 (later)

K160/K161, KV161, L160/L161 (early models)

K160/K161, KV161, L160/L161 (later models)

L181, K181 and M8

K241 and M10

K301 and M12

K330/K331

K321 and M14

K341 and M16

K361 (OHV)

Bore (STD)

2.375"

2.875"

2.938"

2.875"

2.938"

2.938"

3.250"

3.375"

3.625"

3.500"

3.750"

3.750"

Stroke

2.000"

2.500"

2.500"

2.500"

2.500"

2.750"

2.875"

3.250"

3.250"

3.250"

3.250"

3.250"

Cubic Inch Displacement

8.86

16.23

16.94

16.23

16.94

18.64

23.85

29.08

33.54

31.27

35.895

35.895

Minimum Safe Idle Speed

<-1,200 RPM (±75 RPM)->

Factory-Rated Horsepower at Maximum Safe Operating Speed

4hp at 4,000 RPM

6¼hp at 3,200 RPM

7hp at 3,600 RPM

6¼hp at 3,200 RPM | 6.6hp at 3,600 RPM

7hp at 3,600 RPM

8hp at 3,600 RPM

10hp at 3,600 RPM

12hp at 3,600 RPM

12½hp at 3,200 RPM

14hp at 3,600 RPM

16hp at 3,600 RPM

18hp at 3,600 RPM

Valve Size (Head diameter)

Intake

1.262"

1-3/8"

1-3/8"

1-3/8"

1-3/8"

1-3/8"

1-3/8"

1-3/8"

?

1-3/8"

1-3/8"

1-7/16"

Exhaust

1.262"

1-1/8"

1-1/8"

1-1/8"

1-1/8"

1-1/8"

1-1/8"

1-1/8"

?

1-1/8" (Early K321's) 1-3/8" (Later K321's with specification suffix "D" and later, and all M14's)

1-3/8"

1-13/32"

How to Decode the Model Numbers of Kohler K-series and Magnum Engines - These determine the size and basic description of the engine.

Example of Model K161 -> K = K-series engine | 16 = Cubic inch displacement (approximate) | 1 = One/single cylinder engine Example of Model KV161 -> K = K-series engine | V = Vertical crankshaft | 16 = Cubic inch displacement (approximate) | 1 = One/single cylinder engine Example of Model L161 -> L = Liquid-cooled engine | 16 = Cubic inch displacement (approximate) | 1 = One/single cylinder engine Example of Model K301AQS -> K = K-series engine | 30 = Cubic inch displacement (approximate) | 1 = One/single cylinder engine | A = Narrow Base Block and/or Special Oil Pan | Q = Quiet Model "Quiet Line" | S = Electric (Gear) Start Example of Model M14PT -> M = Magnum series engine | 14 = Horsepower rating | PT = Pump model/Retractable start Example of Model KT17 -> K = K-series engine | T = Twin cylinder | 17 = Horsepower rating Example of Model M18 -> M = Magnum engine | 18 = Horsepower rating Example of Model K482 -> K = K-series engine | 48 = Cubic inch displacement (approximate) | 2 = Two (twin) cylinder engine By the way - The model numbers corresponding to Kohler engine models K90/K91, K160/K161, K330/K331, and K660/K662 are basically the same engines, respectively. Beginning in 1965, Kohler changed the "0" to "1" or "2" at the end of the model number to indicate that it's a one (1) or two (2) cylinder engine. The History of Kohler Engines | eHow.

How to Decode the Version Codes for Kohler K-series and Magnum Single- and Opposed Twin-Cylinder Engines - These are the letter(s) immediately following the engine model number, indicating the type of engine.

A = Narrow Base Block w/Narrow Oil Pan and/or Special Oil Pan B = Basic Engine C = Clutch (OEM Kohler Mechanical Clutch Unit)

G = Generator (Electric Power Plant) P = (Water) Pump Q = Quiet Line Model

R = Reduction Gear S = Electric (Gear) Start T = Recoil Start

ST = Electric (Gear) Start and Recoil Start EP = Electric Power Plant (Portable or Stationary Stand-By Generator)

How to Decode the Specification Numbers for Kohler K-series and Magnum Single- and Opposed Twin-Cylinder Engines - The first two numbers of the specification number indicate the engine model. The following three numbers and letter (not shown below) are the specific variation of the engine to meet the original equipment manufacturer's (OEM) specifications. No information is available from Kohler to what these numbers represent. Engine model codes with a 4th digit of 5 or greater denote Magnum engines.

Specification Number = Model(s) of Engine	Specification Number = Model(s) of Engine	Specification Number = Model(s) of Engine	Specification Number = Model(s) of Engine	Specification Number = Model(s) of Engine
26, 27, 31 = K90 and K91	29 = K141	28 = K160, K161 and L160/L161 41, 42 = K160 and K161 (Generator Specs)	30 = K181, L181 and M8	46 = K241 and M10
47 = K301 and M12	60 = K321 and M14	71 = K341 and M16	23 = K361	24 = KT17 (first design), KT17 Series II and M18
49 = KT19 (first design), KT19 Series II and M20	32 = KT21	56 = MV16	58 = MV18	57 = MV20
35 = K482	53 = K532	36 = K582	37, 38, 43, 44 = K330 and 331	29, 30, 33, 39, 45 = K660 and K662

How to Decode the Serial Numbers for Kohler K-series and Magnum Single- and Opposed Twin-Cylinder Engines - The letter or the first two or three numbers of the serial number indicates the year the engine was manufactured. The remaining digits of the serial number are factory code (line/shift at the factory when the engine was assembled on that day; these numbers are for warranty purposes only.) FYI - In 1951, Kohler released the model K90 engine (which is actually the K91). The model K160 (which is actually the K161) followed in 1952. No serial numbers are available these early model engines. In 1968, Kohler expanded into the small all terrain vehicle market by beginning to produce 2-cylinder snowmobile engines. In 1984, Kohler revealed new style and improvements through the Magnum series, complete with electronic ignition and "superior" air filtration system.

Kohler Engine Models K330/K331 12-1/2 Horsepower - Sizes and Running Clearances

PARTS FITTED	SIZE OR CLEARANCE		PARTS FITTED	SIZE OR CLEARANCE
Minimum safe idle speed (RPM) Maximum safe operating speed (RPM)	1,200 3,200		Breaker cam to camshaft pin	.001" - .0025"
Cylinder Bore - STD size	3.625"		Camshaft end play	.005" - .010"
Closure plate to block	.001" - .005"		Tappet in block	.0008" - .0023"
Crankshaft end play - Models with Oil Pump Crankshaft end play - Models with Splash Lubrication	.003" - .008" .005" - .010"		Valve stem in guide - Intake Valve stem in guide - Exhaust	.002" - .005" .002" - .0035"
Connecting rod to crankpin running clearance	.0003" - .0023"		Guide in block	.0005" - .002"
Connecting rod side play on crankpin	.007" - .011"		Exhaust valve seat in block	.0025" - .0045"
Crankshaft connecting rod journal size	1.873"		Transfer bearing to crankshaft, oil clearance	.001" - .0035"
Connecting rod to wrist pin	.0003" - .0008"		Crankshaft gear to crankshaft	.001" - .0015"
Wrist pin to piston boss	.0001" - .0003"		Output shaft seal to closure plate	.001" - .007"
Ring side clearance - top ring	.0025" - .0045"		Governor gear to governor shaft	.0005" - .0015"
Ring side clearance - middle ring	.0025" - .0045"		Piston to cylinder bore clearance (top thrust face)	.0005" - .0015"
Ring side clearance - bottom ring	.002" - .0035"		Valve clearances (cold) - Intake | Exhaust	.008" | .020"
Ring end gap	.007" - .017"		Spark plug gap - Magneto ignition Spark plug gap - Battery ignition	.025" .035"
Camshaft pin to camshaft running clearance	.001" - .0025"		Breaker points gap	.020"
Camshaft pin to block	.0015" - .003"		Spark retard (engine start) Spark advance (engine running)	2º ATDC 15º BTDC

Kohler K-series Single Cylinder Engine Specifications and Tolerances (All dimensions in inches.)

Engine Model

K90/K91

K141, KV161, K160/K161, L160/L161

L181 and K181

K241

K301

K321

K341

K361 (Over Head Valve)

General Information

Minimum Safe Idle Speed (See note 11 below)

<-1,200 RPM (±75 RPM)->

Factory-Rated Horsepower at Maximum Safe Operating Speed

4hp at 4,000 RPM

6¼hp at 3,200 RPM | 6.6hp at 3,600 RPM | 7hp at 3.600 RPM

8hp at 3,600 RPM

10hp at 3,600 RPM

12hp at 3,600 RPM

14hp at 3,600 RPM

16hp at 3,600 RPM

18hp at 3,600 RPM

Bore x Stroke

STD. 2.375" .010" 2.385" .020" 2.395" .030" 2.405" x 2.000"

6¼ and 6.6hp - STD. 2.875" | 7hp - STD. 2.938" .010" 2.948" .020" 2.958" .030" 2.968" x 2.500"

STD. 2.938" .010" 2.948" .020" 2.958" .030" 2.968" x 2.750"

STD. 3.251" .010" 3.261" .020" 3.271" .030" 3.281" x 2.875"

STD. 3.375" .010" 3.385" .020" 3.395" .030" 3.405" x 3.250"

STD. 3.500" .010" 3.510" .020" 3.520" .030" 3.530" x 3.250"

STD. 3.750" .010" 3.760" .020" 3.770" .030" 3.780" x 3.250"

STD. 3.750" .010" 3.760" .020" 3.770" .030" 3.780" x 3.250"

Cubic Inch Displacement (STD Bore)

8.86

16.23 (K141) 16.95 (K161)

18.64

23.85

29.07

31.27

35.90

35.90

Compression Ratio

6.6:1

5.93:1 (K141) 6.2:1 (K161)

6.8:1

5:1, 5.4:1 or 7.1:1 (See note 8 below)

6.2:1, 6.6:1 or 8.6:1 (See note 8 below)

6.6:1, 7:1 or 9:1 (See note 8 below)

7.3:1

9.2:1

Balance Gears (Not necessarily required for K-series engines, or have rotating assembly precision balanced.)

Shaft O.D.

New

-

-

-

<-.4998"-.5001"->

Maximum Wear Limit

-

-

-

<-.4996"->

Clearance/End-Play

-

-

-

<-.002"-.010"->

Camshaft

Clearance/End-Play (See note 10 below)

<-.005"-.010"->

Connecting Rod

Running Clearance (See note 10 below)

Maximum Big End Diameter

STD. size: .938" / .010" undersize: .928"

<-STD. size: 1.1875" / .010" undersize: 1.1775"->

<-STD. size: 1.5015" / .010" undersize: 1.4915" / .020" undersize: 1.4815" / .030" undersize: 1.4715"->

Rod to Crankpin

.001" (min.) .0025"

<-.001"-.002"->

Maximum Rod to Crankpin Wear Limit

.003"

<-.0025"->

Rod to Piston Pin

.0007" (min.) .0008"

<-.0006"-.0011"->

<-.0003"-.0008"->

Wrist Pin Hole I.D.

.5630" (min.) .5633"

<-.6255"-.6258"->

.8596" (min.) .8599"

<-.8757"-.8760"->

Crankshaft

Main PTO end and Flywheel End O.D.

New

.9844"

<-1.1814"->

<-1.5749"->

Maximum Wear Limit

.9841"

<-1.1811"->

<-1.5745"->

Crankpin

New (max./min.) (See note 10 below)

STD. size: .9360"-.9355" .010" undersize: .9260"-.9255"

<-STD size: 1.1860"-1.1855", .010" undersize: 1.1760"-1.1755"->

STD size: 1.4995"-1.5000", .010" undersize: 1.4895"-1.4900", .020" undersize: 1.4795"-1.4800", .030" undersize: 1.4695"-1.4700"

Maximum Wear Limit

STD. .9350" .010" .9340"

<-STD. size: 1.1850" / .010" undersize: 1.1840"->

<-STD. size: 1.4990" / .010" undersize: 1.4890" / .020" undersize: 1.4790" / .030" undersize: 1.4690"->

Maximum Out of Round

<-.0005"->

Maximum Taper

<-.001"->

clearance/end-play (See note 10 below)

.004" (min.) .023"

<-.002"-.023"->

<-.003"-.020"->

Cylinder Bore

Standard Size Cylinder Bore Diameter

New (See note 10 below)

2.3745"-2.3755"

<-2.9370"-2.9380"->

3.2505"-3.2515"

3.3745"- 3.3755"

3.4995"- 3.5005"

3.7495"-3.7505"

3.7495"-3.7505"

Maximum Wear Limit

2.378"

2.941"

2.941"

3.254"

3.378"

3.503"

3.753"

3.753"

Cylinder Bore Diameter for Oversize Piston/Rings

.010" = 2.385" .020" = 2.285" .030" = 2.405"

.010" = 2.9475" .020" = 2.9575" .030" = 2.9675"

.010" = 2.9475" .020" = 2.9575" .030" = 2.9675"

.010" = 3.260" .020" = 3.270" .030" = 3.280"

.010" = 3.385" .020" = 3.395" .030" = 3.405"

.010" = 3.510" .020" = 3.520" .030" = 3.530"

.010" = 3.760" .020" = 3.770" .030" = 3.780"

.010" = 3.760" .020" = 3.770" .030" = 3.780"

Maximum Out of Round

<-.003"->

Maximum Taper

<-.003"->

<-.002"->

Cylinder Head

Maximum Out of Flatness

<-.003"->

Ignition

Correct Spark Plug Type and Gap

Type (See note 2 below)

Autolite 255 or Champion 861 (J19LM)

<-Autolite 295 or Champion 841 (J8C)->

<-Autolite 216 or Champion 884 (H10C)->

Magneto

<-.025"->

Battery

<-.035"->

LP/Propane

<-.018"->

Point Gap

Magneto

<-If no spark at .020" point gap, set gap between .015"-.018" for a stable spark and so the engine will run->

Battery (See note 12 below)

<-Set point gap at .020" or set timing at 20º BTDC->

All Pistons

Service Replacement Sizes

<-.010", .020", .030"->

.010", .020", .030"

<-.010", .020", .030", .040" (aftermarket)->

(K-series Cast Piston)

Thrust Face O.D. (See note 3 below)

New

2.371"-2.369"

<-2.866" (K141) 2.9297"-2.9281" (K161, K181, L181)->

3.2432"-3.2413"

3.368"-3.365"

3.4941"-3.4925"

<-3.7425"-3.7410"->

Maximum Wear Limits

2.366"

2.925"

2.925"

3.238"

3.363"

3.491"

<-3.738"->

Thrust Face to Bore Clearance (max.) (See note 1 below)

.0035"-.006"

<-.007"-.010"->

Ring End Gap (All 3 rings; see note 1 below)

New Bore (See note 10 below)

<-.007"-.017"->

<-.010"-.020"->

Used Bore (Maximum) (See note 6 below)

<-.027"->

<-.030"->

Maximum Ring Side Clearance

<-.006"->

(K-series Cast Piston)

Thrust Face O.D. (See note 5 below)

New

3.371"-2.369"

2.9279"-2.9281"

2.9279"-2.9281"

3.2432"-3.2413"

3.368"-3.365"

3.4941"-3.4925"

<-3.7425"-3.7410"->

Maximum Wear Limits

2.366"

2.925"

2.925"

3.238"

3.363"

3.491"

<-3.738"->

Thrust Face to Bore Clearance (max.) (See note 1 below)

.0035"-.006"

.007"-.010"

.007"-.010"

.007"-.010"

.007"-.010"

.007"-.010"

<-.007"-.010"->

Ring End Gap (All 3 rings.)

New Bore (See note 10 below)

.007"-.017"

.007"-.017"

.007"-.017"

.010"-.020"

.010"-.020"

.010"-.020"

<-.010"-.020"->

Used Bore (Maximum) (See note 6 below)

.027"

.027"

.027"

.030"

.030"

.030"

<-.030"->

Maximum Ring Side Clearance

.006"

.006"

.006"

.006"

.006"

.006"

<-.006"->

(Magnum Mahle Piston)

Thrust Face O.D. (See notes 5, 9 below)

New / Used

-

-

2.9329"-2.9336"

-

3.3700"-3.3693"

3.4945"-3.4938"

<-3.7433"-3.7426"->

Maximum Wear Limits

-

-

2.931"

-

3.367"

3.492"

<-3.7406"->

Thrust Face to Bore Clearance (See notes 1, 9 below)

-

-

.0034"-.0051"

-

.0045"-.0062"

.0050"-.0067"

<-.0062"-.0079"->

Ring End Gap (All 3 rings.)

New Bore (See note 10 below)

-

-

.010"-.023"

-

<-.010"-.020"->

<-.013"-.025"->

Used Bore (Maximum) (See note 6 below)

-

-

.032"

-

<-.030"->

<-.033"->

Maximum Ring Side Clearance

-

-

.006"

-

<-.006"->

<-.004"->

Wrist Pin Outside Diameter (min.-max.)

.5623"-.5625"

<-.6247"-.6249"->

.8591"-.8593"

<-.8752"-.8754"->

Valves

Valve Head Diameter

Intake: 63/64" Exhaust: 51/64"

<-Intake: 1-3/8" Exhaust: 1-1/8"->

<-Intake: 1-3/8" Exhaust: 1-1/8"->

Intake: 1-3/8" Exhaust: 1-1/8" (early) / 1-3/8" (late)

Intake: 1-3/8" Exhaust: 1-3/8"

Intake: 1-7/16" Exhaust: 1-13/32"

Guide Reamer Size

.250"

<-.3125"->

<-.3125"->

Tappet Clearance (Cold) (See notes 4, 9 below)

Intake (min.-max.)

.005"-.009"

<-.006"-.008"->

<-.008"-.010"->

.005"-.008"

Exhaust (min.-max.)

.011"-.015"

<-.017"-.019"->

<-.017"-.019"->

.010"-.012"

Minimum Lift (Zero Lash)

Intake

.2035"

<-.2718"->

<-.318"->

Exhaust

.1768"

<-.2482"->

<-.318"->

Minimum Stem O.D.

Intake

.2478"

<-.3103"->

Exhaust

.2458"

<-.3088"->

<-.3074"->

Minimum Valve Head Margin (Width)

<-.030"->

Face / Seat Angle

<-45º / 46º->

Guide I.D. Maximum Wear Limit (See note 1 below)

Intake

<-.005"->

<-.006"->

Exhaust

<-.007"->

<-.008"->

Lifter to Bore Clearance

<-.001"-.0015"->

NOTES -

NOTE 1 - Subtract O.D. of inner part from I.D. of outer part. Use the lesser clearance for a stock engine (up to 4,000 RPM), and the greater number for a higher RPM engine. Higher RPM creates more heat due to friction, which causes greater expansion of parts. Also, when boring or honing for piston clearance, it's important to check the ring end gaps and gap them according to Kohler's specs. NOTE 2 - For longevity of the coil and to prevent overheating of the coil, use only metal core spark plug wire and copper core/non-resistor spark plugs. NOTE 3 - Measure just below oil ring groove and at right angles to wrist pin. NOTE 4 - 1,800 RPM generator sets at .005"- 007". NOTE 5 - Measure 1/2" above the bottom of the piston skirt. NOTE 6 - Top and center compression rings. NOTE 7 - Measure just below oil ring groove and at right angles to wrist pin. NOTE 8 - Compression ratio depends on which cylinder head is used.

NOTE 9 - Use the lesser clearance is for a valve that have been ran for a while, and use the greater clearance for a fresh reground valve face and seat (As the valve and seat wear into each other, the clearance will be lessened over time.) NOTE 10 - Use the lesser clearance for up to 3,600 RPM operation, and use the greater clearance for open RPM. NOTE 11 - Idle speed should be set at 1,200 RPM (±75 RPM) so the oil dipper can lubricate the internal moving parts more thoroughly. This speed also allows the flywheel fins to blow adequate amount of air across the cylinder head and around the cylinder fins to cool the engine better. NOTE 12 - For early model engines with the 2-piece camshaft and automatic timing advance, set points so they just begin to open when piston is positioned at top dead center (TDC) on the compression stroke. And for later model engines with the 1-piece camshaft and automatic compression release (ACR), set point gap at .020" with piston positioned at top dead center (TDC) on the compression stroke, or set static ignition timing when points begin to open exactly when S mark on flywheel passes raised line on bearing plate or hole in bearing plate.

Kohler Magnum Single Cylinder Engine Specifications and Tolerances (All dimensions in inches)

Engine Model			M8	M10	M12	M14	M16
General Information	Minimum Safe Idle Speed (See note 9 below)		<-1,200 RPM (±75 RPM)->
	Factory-Rated Horsepower at Maximum Safe Operating Speed (See note 8 below)		7hp at 3,200 RPM 8hp at 3,600 RPM	9hp at 3,200 RPM | 10hp at 3,600 RPM	10.6hp at 3,200 RPM | 12hp at 3,600 RPM	12.4hp at 3,200 RPM 14hp at 3,600 RPM	14.2hp at 3,200 RPM 16hp at 3,600 RPM
	Bore x Stroke		STD. 2.938" .010" 2.948" .020" 2.958" .030" 2.968" x 2.750"	STD. 3.251" .010" 3.261" .020" 3.271" .030" 3.281" x 2.875"	STD. 3.375" .010" 3.385" .020" 3.395" .030" 3.405" x 3.250"	STD. 3.500" .010" 3.510" .020" 3.520" .030" 3.530" x 3.250"	STD. 3.750" .010" 3.760" .020" 3.770" .030" 3.780" x 3.250"
	Cubic Inch Displacement (STD Bore)		18.64	23.85	29.07	31.27	35.90
Balance Gears (These may be required for Magnum engines, or have rotating assembly precision balanced.)	Shaft O.D.	New	-	<-.4998"-.5001"->
		Maximum Wear Limit	-	<-.4996"->
	Clearance/End-Play		-	<-.002"-.010"->
Camshaft	Clearance/End-Play (See note 6 below)		<-.005"-.010"->
Connecting Rod	Running Clearance	Maximum Big End Diameter	STD. 1.1875" .010" 1.1775"	<-STD. 1.5015" / .010" 1.4915" / .020" 1.4815" / .030" 1.4715"->
		Rod to Crankpin (max.)	<-.001"-.002"->
		Rod to Crankpin - Maximum Wear Limit	<-.0025"->
		Rod to Wrist Pin (max.)	.0006"-.0011"	<-.0003"-.0008"->
	Small End I.D. (max.)		.6255"-.6258"	.8596"-.8599"	<-.8757"-.8760"->
Crankshaft	Main PTO end and Flywheel End O.D.	New	1.1811"-1.1814"	<-1.5745"-1.5749"->
		Maximum Wear Limit	1.1811"	<-1.5745"->
	Crankpin	New - O.D.	STD. 1.186"-1.1855" .010" 1.176"-1.1755"	<-STD. 1.4995"-1.5000", .010" 1.4895"-1.4900", .020" 1.4795"-1.4800", .030" 1.4695"-1.4700"->
		Maximum Wear Limit	STD. 1.1850" .010" 1.1840"	<-STD. 1.4990", .010" 1.4890", .020" 1.4790", .030" 1.4690"->
		Maximum Out of Round	<-.0005"->
		Maximum Taper	<-.001"->
	clearance/end-play (See note 6 below)		.002"-.023"	<-.003"-.020"->
Cylinder Bore	Inside Diameter	New (See note 6 below)	2.9370"-2.9380"	3.2505"-3.2515"	3.3745"-3.3755"	3.4995"-3.5005"	3.7495"-3.7505"
		Maximum Wear Limit	2.941"	3.254"	3.378"	3.503"	3.753"
	Maximum Out of Round (I.D.)		<-.005"->
	Maximum Taper (I.D.)		.003"	<-.002"->
Cylinder Head		Maximum Out of Flatness	<-.003"->
Ignition (Solid State)	Spark Plug	Type (See note 2 below)	Autolite 295 or Champion 841 (J8C)	<-Autolite 316 or Champion 884 (H10C)->
		Gap	<-.025"->
	Armature Air Gap		<-.010"-.012"->
	Ignition Timing		<-Not Applicable/Fixed Timing (20º BTDC)->
All Pistons	Service Replacement Sizes		<-.003", .010", .020", .030"->		<-.003", .010", .020", .030", .040" (aftermarket)->
(K-series Cast Piston)	Thrust Face O.D. (See note 3 below)	New (See note 6 below)	2.9297"-2.9281	3.2432"-3.2413	3.368"-3.365	3.4941"-3.4925	-
		Maximum Wear Limits	2.925"	3.238"	3.363"	3.491"	-
	Thrust Face to Bore Clearance (max.) (See notes 1, 6 below)		<-.007"-.010"->				-
	Ring End Gap (All 3 rings; see note 1 below)	New Bore (See note 7 below)	.007"-.017"	<-.010"-020"->			-
		Used Bore (Maximum) (See note 5 below)	.027"	<-.030"->			-
	Maximum Ring Side Clearance		<-.006"->				-
(K-series Cast and Magnum Mahle Pistons)	Thrust Face O.D. (See note 4 below)	New	-				3.7465"-3.7455"
		Maximum Wear Limits	-				3.7435"
	Thrust Face to Bore Clearance (max.) (See note 1 below)		-				.003"-.005"
	Ring End Gap (All 3 rings.)	New Bore (See note 7 below)	-				.010"-020"
		Used Bore (Maximum) (See note 5 below)	-				.030"
	Maximum Ring Side Clearance		-				.004"
(Magnum Mahle Piston)	Thrust Face O.D. (See note 4 below)	New (See note 6 below)	2.9329"-2.9336"	-	3.3700"-3.3693"	3.4945"-3.4938"	3.7433"-3.7426"
		Maximum Wear Limits	2.9312"	-	3.3673"	3.4918"	3.7406"
	Thrust Face to Bore Clearance (max.) (See note 1, 6 below)		.0034"-.0051"	-	.0045"-.0062"	.0050"-0067"	.0062"-.0079"
	Ring End Gap (All 3 rings.)	New Bore (See note 7 below)	.010"-.023"	-	<-.010"-.020"->		.013"-.025"
		Used Bore (See note 5 below)	.032"	-	<-.030"->		.033"
	Maximum Ring Side Clearance		.006"	-	<-.006"->		.004"
Wrist Pin	Outside Diameter		.6247"-.6249"	.8591"-.8593"	<-.8752"-.8754"->
Valves	Valve Head Diameter		<-Intake: 1-3/8" / Exhaust: 1-1/8"->			<-Intake: 1-3/8" / Exhaust: 1-3/8"->
	Guide Reamer Size		<-.3125"->
	Tappet Clearance (Cold) (see note 6 below)	Intake (min.-max.)	.006"-.008"	<-.008"-.010"->
		Exhaust (min.-max.)	<-.017"-.019"->
	Minimum Lift (Zero Lash)	Intake	.2718"	<-.318"->
		Exhaust	.2482"	<-.318"->
	Minimum Stem O.D.	Intake	<-.3103"->
		Exhaust	<-.3074"->
	Face / Seat Angle		<-45º / 46º->
	Guide I.D. Maximum Wear Limit (See note 1 below)	Intake	<-.006"->
		Exhaust	<-.008"->
		Lifter to Bore Clearance	<-.001"-.0015"->

NOTES:

NOTE 1 - Subtract O.D. of inner part from I.D. of outer part. Use the lesser clearance for a stock engine (up to 4,000 RPM), and the greater number for a higher RPM engine. Higher RPM creates more heat due to friction, which causes greater expansion of parts. NOTE 2 - For longevity of the coil and to prevent overheating of the coil, use only copper core/non-resistor spark plugs. NOTE 3 - Measure just below oil ring and at right angles to wrist pin. NOTE 4 - Measure 1/2" above the bottom of the piston skirt. NOTE 5 - Top and center compression rings. NOTE 6 - Use the lesser clearance is for a valve that have been ran for a while, and use the greater clearance for a fresh reground valve face and seat (As the valve and seat wear into each other, the clearance will be lessened over time.)

NOTE 7 - Use the lesser clearance for up to 3,600 RPM operation, and use the greater clearance for open RPM. NOTE 8 - To prevent a lean air/fuel mixture when using a Walbro carburetor with a fixed/non-adjustable high speed main jet, set maximum engine speed at 3,200 RPM. But if using a Carter, Kohler or Walbro carburetor with a fully adjustable high speed main jet, maximum engine speed can be set at 3,600 RPM. NOTE 9 - Idle speed should be set at 1,200 RPM (±75 RPM) so the oil dipper can lubricate the internal moving parts more thoroughly. This speed also allows the flywheel fins to blow adequate amount of air across the cylinder head and around the cylinder fins to cool the engine better.

Kohler Opposed (Flathead) Twin Cylinder Engine Specifications and Tolerances (All dimensions in inches.)

Engine Model	MV16	M18, MV18	M20, MV20	KT17 (first design), KT17 Series II	KT19 (first design), KT19 Series II	KT21	K482	K532	K582	K660/K662
Minimum Safe Idle Speed (See note 11 below)	<-1,200 RPM (±75 RPM)->
Factory-Rated Horsepower at Maximum Safe Operating Speed (See note 2 below)	14.2hp at 3,200 RPM 16hp at 3,600 RPM	16hp at 3,200 RPM 18hp at 3,600 RPM	17.8hp at 3,200 RPM 20hp at 3,600 RPM	17hp at 3,600 RPM	19hp at 3,600 RPM	21hp at 3,600 RPM	18hp at 3,600 RPM	20hp at 3,600 RPM	23hp at 3,600 RPM	24hp at 3,200 RPM
Engine Construction	<-Two-Piece Aluminum Crankcase w/Incorporated Cast Iron Barrels/Cylinders/Jugs-> (Use a thin bead of Clear RTV Silicone Adhesive Sealant on crankcase halves and barrels/cylinders/jugs when reassembling these engines.)						<-One-Piece Cast Iron Crankcase w/Integrated Cylinders->
Cubic Inch Displacement (STD Bore)	42.18	42.18	47.00	42.18	47.00	52.76	47.70	53.68	57.70	67.20
Compression Ratio	5.8:1	6:1	M20 - 6.6:1 MV20 - 6:1	6:1	6.7:1	7.3:1	5.8:1	6.4:1	7:1	?
Cylinder Bore (New)	<-3.125"->					3.312"	3.250"	3.375"	3.500"	3.625"
Cylinder Bore (Worn)	<-3.128"->					3.315"	3.253"	3.378"	3.503"	3.6245"
Crankshaft Stroke	<-2.750"->		3.062"	2.750"	3.062"	3.062"	2.875"	3.000"	3.000"	3.250"
Cylinder Taper	<-.0015"->									.002"
Cylinder Out of Round	<-.002"->						<-.005"->
Crankshaft Clearance/End-Play (Engines w/Sleeve Bearing)	<-.002"-.014"->						<-.004"-.010"->			.0035"-.0055"
Crankshaft Clearance/End-Play (Engines w/Ball Bearing)	<-.002"-.023"->						--
Crankshaft Main Journals Diameter (Engines w/Sleeve Bearing)	<-STD size: 1.742", .010" undersize: 1.732", .020" undersize: 1.722"->						<-STD size: 1.750", .010" undersize: 1.740", .020" undersize: 1.730"->
Crankshaft Main Journals Diameter (Engines w/Ball Bearing)	<-1.378"->						<-1.772"->
Crankshaft Main Sleeve Bearing Oil Clearance	<-.0013"-.0033"->						<-.0015"-.004"->			?
Crankpin (Rod Journal) New Diameter	<-1.3733"-1.3738"->		1.500"	1.3733"-1.3738"	first design - 1.3733"-1.3738" Series II - 1.4993"-1.4998"	1.7422"-1.7421"	<-1.625"->			?
Crankpin Out of Round	<-.0005"->									?
Crankpin Maximum Taper	<-.001"->									?
Camshaft Clearance	<-.001"-.0025"->						<-.0005"-.0045"->			?
Camshaft End Float	<-.003"-.013"->						<-.017"-.038"->			?
Connecting Rod Big End Maximum Diameter	<-1.376"->		1.5010"-1.5017"	1.376"	first design - 1.376" Series II - 1.5025"	1.5010"-1.5017"	<-1.627"->			?
Connecting Rod Big End to Crank Pin Clearance	<-KT17 (first design), KT19 (first design) and KT21 Engines: .0015"-.0025"-> <-KT17 Series II, KT19 Series II, All Magnums, K482, K532, K582 and K662 Engines: .0012"-.0024"->
Connecting Rod Small End Pin New Diameter	<-0.62565"->		0.7511"	0.62565"	0.7511"	.85975"	.8596"	<-0.87585"->		.8752"-.8754"
Connecting Rod Small End Clearance	<-.0006"-.0011"->						<-.0003"-.0008"->			?
Piston Thrust Face Maximum Wear Diameter (See note 1 below)	<-3.1165"->						3.2375"	3.3625"	3.4945"	3.624"-3.6235"
Piston Thrust Face to Bore Clearance	<-.0035"-.0052"->		.0030"-.0047" (M20) .0035"-.0052" (MV20)	.006"-.008"	.0065"-.0085"	.0065"-.0085"	<-.007"-.010"->			?
Piston Rings Maximum Side Clearance	<-.004"->						<-.006"->			?
Piston Rings Gap (New)	<-.010"-.020"->									.010"-.020"
Piston Rings Gap Maximum (Used)	<-.030"->									?
Intake Valve to Tappet Clearance Cold See note 12 below	<-.003"-.006"->						<-.008"-.010"->			.006"-.008"
Exhaust Valve to Tappet Clearance Cold See note 12 below	<-.011"-.014"->						<-.017"-.020"->			.017"-.019"
Intake Valve Maximum Lift (Zero Valve-Tappet Clearance)	<-0.280"->						<-0.324"->			?
Exhaust Valve Maximum Lift (Zero Valve-Tappet Clearance)	<-0.280"->						<-0.324"->			?
Intake Valve Stem-Guide Clearance Maximum	<-.0045"->									?
Exhaust Valve Stem-Guide Clearance	<-.0065"->									?
Cam Follower (Lifter/Tappet) Clearance in Guide	<-.0005"-.0024"->						<-.0012"-.0023"->			?
Spark Plug Type (See note 8 below)	<-Autolite 26 or Champion 25 (RV17YC)->						<-Autolite 316 or Champion 884 (H10C)->			<-Autolite 295 or Champion 841 (J8C)->
Spark Plug Gap Magneto/Solid State Ignition	<-.025"->			<-N/A->			<-.025"->
Spark Plug Gap Battery Ignition	<-N/A->			<-.025"->			<-.035"->			.025"
Spark Plug Gap - Gaseous Fuel (Propane/LP)	<-.018"->
Ignition Points Gap	<-N/A->			<-.017"-023" (See note 6 below)->			<-.020"->
Ignition Timing Spark Run	<-N/A-> (Timing fixed at 23º BTDC)			<-23º BTDC->			<-22.5º BTDC->			When Marks Are Aligned in Sight Hole
Spark Plug Torque	<-11-15 ft. lbs.->						<-18-22 ft. lbs.->
Cylinder Head Torque	<-15-20 ft. lbs.->						<-35 ft. lbs.->			?
Connecting Rod Nut/Bolt Torque	<-200 in. lbs.->						<-200 in. lbs (See note 4 below)->			?
Flywheel Nut / Screw Torque See note 5 below)	<-40 ft. lbs.->						<-115 ft. lbs.->			130 ft. lbs.

NOTES -

NOTE 1 - Measure just below oil ring and at right angle to piston pin. NOTE 2 - To prevent a lean air/fuel mixture when using a Walbro carburetor with a fixed/non-adjustable high speed main jet, set maximum engine speed at 3,200 RPM. But if using a Carter, Kohler or Walbro carburetor with a fully adjustable high speed main jet, maximum engine speed can be set at 3,600 RPM. NOTE 3 - 1,800 RPM Generator Engines .015" Spark Plug Gap and 16º before top dead center (BTDC) Timing. NOTE 4 - 3/8" Screw - 300 in. lb. NOTE 5 - 5/16" Screw - 250 in. lbs. NOTE 6 - Or set static ignition timing when points begin to open exactly when S mark on flywheel passes roll pin on #1 cylinder.

NOTE 7 - Measure just below oil ring groove and at right angles to wrist pin. NOTE 8 - Compression ratio depends on which cylinder head is used. NOTE 8 - For longevity of the coil and to prevent overheating of the coil, use only metal core spark plug wires and copper core/non-resistor spark plugs. NOTE 11 - Idle speed should be set at 1,200 RPM (±75 RPM) so the oil dipper can lubricate the internal moving parts more thoroughly. This speed also allows the flywheel fins to blow adequate amount of air across the cylinder head and around the cylinder fins to cool the engine better. NOTE 12 - Use the lesser clearance is for a valve that have been ran for a while, and use the greater clearance for a fresh reground valve face and seat (As the valve and seat wear into each other, the clearance will be lessened over time.)

Model (Horsepower)		K90/91	K141, K160/K161	K181, L181 and M8	K241, M10, K301, M12, K321 and M14	K341 and M16	K361 (Over Head Valve)	KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20, MV20
Connecting Rod Nuts/Bolts (See notes 1, 2, 3 and 4 below)	Posi-Lock (Flange Nut/Stud)	-	-	New 140 in. lb. / 12 ft. lb. Used 100 in. lb. / 9 ft. lb.	<-New 260 in. lb. / 22 ft. lb.-> <-Used 200 in. lb. / 17 ft. lb.->			New 140 in. lb. / 12 ft. lb. Used 100 in. lb. / 9 ft. lb.
	Capscrew (Bolt)	140 in. lb. / 12 ft. lb.	<-200 in. lb. / 17 ft. lb.->		<-285 in. lb. / 24 ft. lb.->
Spark Plug		<-180-240 in. lb. / 15-20 ft. lb.->
Cylinder Head Torque Sequences and Torque Values (See note 1 below)		15 ft. lb. / 200 in. lb.	15-20 ft. lb. / 180-240 in. lb.		25-30 ft. lb. / 300-360 in. lb.	25-30 ft. lb. / 300-360 in. lb.	25-30 ft. lb. / 300-360 in. lb.	15-20 ft. lb. / 180-240 in. lb.
Flywheel Retaining Nut or Bolt (See note 6 below)	5/8" or 3/4" Nut (See note 1, 6 below)	45 ft. lb.	50 ft. lb. (See note 4 below)		<-65 ft. lb.->			-
	3/8" Bolt (See note 1, 6 below)	250 in. lb.	-		<-24-35 ft. lb.->
Governor Bushing		80 in. lb.	140 in. lb.		<-110 in. lb.->			-
Grass Screen	Metal	-	70 - 140 in. lb.		<-70 - 140 in. lb.->
	Plastic	-	-		20-30 in. lb.
Oil Pan	Cast Iron or Aluminum (See note 1 below)	250 in. lb.	Grade 5 - 250 in. lb. Grade 8 - 350 in. lb.		<-35 ft. lb.->			-
	Sheet Metal (See note 1 below)	-	-		<-200 in. lb.->			-
Plastic Fuel Pump Mounting Screws		-	<-40 in. lb.->

NOTES:

NOTE 1 - Lubricate fastener threads with motor oil. NOTE 2 - DO NOT overtorque - DO NOT loosen and retorque the hex nuts on Posi-Lock connecting rods. NOTE 3 - Overtorque 20%, loosen below torque value and retorque to final torque value. NOTE: Overtorquing rod bolts 20% places stress on the threads in a NEW aluminum rod. This allow for proper tightness so bolts won't loosen later. Used rods: Torque to 285 in. lbs. one time only.

NOTE 4 - To prevent rod bolts from loosening, install a split lock washer on each bolt and then torque to specs. Posi-Lock (flange) nuts doesn't require a lock washer. NOTE 5 - Prior to Serial No. 23209832 - 45-55 ft. lb. NOTE 6 - Flywheel and crankshaft tapers must be clean and dry.

Kohler Engine Models K482, K532, K582 and K660/K662 Torque Values and Sequences for Fasteners

Engine Model Maximum HP at 3,600 RPM	K482 18hp	K532 20hp	K582 24hp	K660/K662 24hp
Connecting Rods	5/16" bolt - 200 in. lb. 3/8" bolt - 300 in. lb.			35 ft. lb.
Spark Plugs	216-264 in. lb. / 18-22 ft. lb.
Cylinder Head
Flywheel Nut	115 ft. lb.			139 ft. lb.
Grass Screen	70-138 in. lb.
Oil Pan	Aluminum - 30 ft. lb. Cast Iron - 35 ft. lb.			45 ft. lb.
Manifold Screw/Nut	210 in. lb.			300 in. lb.
Camshaft Nut	40 ft. lb.			25 ft. lb.
Closure Plate	30 ft. lb.			50 ft. lb.

- Identification of Most Commonly Used Grades of Bolts -

Use Standard Torque Settings When Specific Values Are Not Specified (C) = Coarse thread, (F) = Fine thread

Hardness	No Lines = Grade 3	3 Lines = Grade 5	6 Lines = Grade 8	Stainless Steel / Special Alloy
Bolt Size	Material: Low Carbon Steel. Tensile Strength: 85,000 P.S.I. (Low Strength)	Material: Medium Carbon Steel, Tempered. Tensile Strength: 120,000 P.S.I. (Medium Strength)	Material: Medium Carbon Alloy Steel, Quenched and Tempered. Tensile Strength: 150,000 P.S.I. (High Strength)	Material: 18-8 [304] Stainless Steel. Tensile Strength: 130,000 P.S.I.
1/4-20 (C) 1/4-28 (F) 5/16-18 (C) 5/16-24 (F) 3/8-16 (C) 3/8-24 (F) 7/16-14 (C) 7/16-20 (F) 1/2-13 (C) 1/2-20 (F) 9/16-12 (C) 9/16-18 (F) 5/8-11 (C) 5/8-18 (F) 3/4-10 (C) 3/4-16 (F)	70 in. lb. / 6 ft. lb. 85 in. lb. / 7 ft. lb. 150 in. lb. / 13 ft. lb. 165 in. lb. / 14 ft. lb. 260 in. lb. / 22 ft. lb. 300 in. lb. / 25 ft. lb. ------------- 35 ft. lb. ------------- 45 ft. lb. ------------- 50 ft. lb. ------------- 70 ft. lb. ------------- 75 ft. lb. ------------ 100 ft. lb. ------------ 110 ft. lb. ------------ 140 ft. lb. ------------ 150 ft. lb. ------------ 200 ft. lb.	115 in. lb. / 10 ft. lb. 140 in. lb. / 12 ft. lb. 250 in. lb. / 21 ft. lb. 270 in. lb. / 23 ft. lb. ------------- 35 ft. lb. ------------- 40 ft. lb. ------------- 55 ft. lb. ------------- 75 ft. lb. ------------- 80 ft. lb. ------------ 105 ft. lb. ------------ 125 ft. lb. ------------ 165 ft. lb. ------------ 180 ft. lb. ------------ 230 ft. lb. ------------ 245 ft. lb. ------------ 325 ft. lb.	165 in. lb. / 14 ft. lb. 200 in. lb. / 17 ft. lb. 350 in. lb. / 29 ft. lb. ------------ 30 ft. lb. ------------ 50 ft. lb. ------------ 60 ft. lb. ------------ 80 ft. lb. ------------ 105 ft. lb. ------------ 115 ft. lb. ------------ 165 ft. lb. ------------ 175 ft. lb. ------------ 230 ft. lb. ------------ 260 ft. lb. ------------ 330 ft. lb. ------------ 350 ft. lb. ------------ 470 ft. lb.	165 in. lb. / 14 ft. lb. 200 in. lb. / 17 ft. lb. 350 in. lb. / 29 ft. lb. ------------ 35 ft. lb. ------------ 58 ft. lb. ------------ 69 ft. lb. ------------ 98 ft. lb. ------------ 110 ft. lb. ------------ 145 ft. lb. ------------ 160 ft. lb. ------------ 200 ft. lb. ------------ 220 ft. lb. ------------ 280 ft. lb. ------------ 310 ft. lb. ------------ 490 ft. lb. ------------ 530 ft. lb.

Kohler Engine Service and Repair Manuals Contains all the information needed to disassemble, repair and reassemble your Kohler engine. By clicking the links below, a new website will open, containing the manual in PDF file format, which can be saved on your computer and/or printed out. PDF files require Adobe Acrobat Reader. Visit https://pswusers.arinet.com/kohler, scroll to the bottom of website., click on Login as Guest for information concerning Kohler engines.

Kohler Engine Models K161 (Air Cooled) and L160/L161 (Liquid-Cooled) 7hp Parts Manual Kohler Engine Model K181, L181 (Air- and Liquid-Cooled) 8hp Parts Manual Kohler K-series Engine Models K91 through K341 4-16hp Service Manual Kohler K-series Engine Model K361 Service Manual Kohler Engine Models K330/K331 Service Manual | Parts Manual Kohler Magnum Engine Models M8 through M16 Service Manual

Kohler KT-series Engine Models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21 Service Manual Kohler Magnum Engine Models M18 and M20 Service Manual Kohler Magnum Engine Models MV16, MV18 and MV20 Service Manual Kohler Engine Models K482, K532, K582 and K662 Service Manual Kohler Engine Models K660-K662 Parts Manual Kohler Command V-Twin Engine Models CH18-CH25, CH620-CH730, CH740 and CH750 Service Manual

Rare, Vintage VERTICAL SHAFT Kohler cast iron block engine models KV161 and KV331 -

For anyone who is interested in very rare Kohler K-series engines, there's the Kohler cast iron engine models KV161 and KV331 that came in the VERTICAL () crankshaft orientation. The horizontal version of the KV161 is the K160/K161, and the horizontal version of the KV331 is the K330/K331. Anyway, These vertical shaft engines were probably manufactured sometime during the early to mid-60's. The KV161 was used in a small Wheel Horse riding mower and perhaps a water pump, and the KV331 was probably used in a larger riding mower and maybe a water pump. Kohler apparently made these vertical shaft engines in competition with Briggs & Stratton's, (Clinton's?) and Tecumseh's vertical shaft engines, but perhaps failed to keep up with production or the supply and demand at the time, or maybe there was a cost overrun. FYI - Unlike the horizontal shaft engines, which have the flywheel and PTO on the sides (), the vertical shaft engines have the flywheel on top and PTO on the bottom (). The carburetor on certain KV161 engines have either a horizontal or vertical throttle shaft. Click the photo of the model KV161 engine shown here.

I contacted Kohler and asked them for any information regarding these vertical shaft engines, and they said that they have no information or documentation whatsoever and no records are stored for these engines. But an older Kohler engine tech that I spoke with on the phone told me these engines were used to power a water pump. But they could also have been used on a riding mower.

Many years ago, I personally seen a VERTICAL shaft KV161 engine block sitting on the counter of a local machine shop. It had the OEM red paint, too. (Obviously for a Wheel Horse.) And I've seen an [undoctored] photo of the VERTICAL shaft KV331 engine on the Internet several years ago, but never seen one in person. These vertical shaft engines was rare back in the day and is extremely hard to find or next to impossible to find nowadays. If anyone have information or photos regarding these engines that they would like to share in this website, please let me know and I will post it/them in this article with your name for full credit. Go here to see other KV161 engines.

Rare, Vintage LIQUID-COOLED Kohler cast iron block engine models L160/L161 and L181 -

The rare Kohler engine models L160/L161 and L181 are a liquid-cooled version as Kohler's air-cooled engine models K141, K160/K161 and K181. Just like with most automotive engines, these liquid-cooled engines have an impeller water pump and radiator, and require anti-freeze/water mix to maintain the engine's operating temperature. The L160/L161 and L181 engines were obviously used in extreme heat desert-like conditions for long periods of time to prevent overheating of the engine. The liquid-cooled Kohler engine model L160/L161 with specification numbers 4149F, 4150F, 4152E, 4166F, 4167F, 4168E, 4168G, 4168H, 4173E, 4192E, 4194F, 4195F, 4199G, 4199H, 41101F, 41109F, 4110F, 41117F, 41131F and 41137F are listed as generator (power plant) engines, and the liquid-cooled Kohler engine model L181 with specification numbers 42583H, 42594H, 42597H, 42626H, 42723H, 42745H, 42746H are also listed as generator (power plant) engines. These are very rare engines. Go here to see a complete Liquid-Cooled Kohler L160/L161 or L181 Engine. If anyone have information or additional photos regarding these engines that they would like to share in this website, please let me know and I will post it/them in this article with your name for full credit. [Return To Previous Paragraph, Section or Website]

Differences Between the Kohler K-series and Magnum Single Cylinder Engine Blocks -

Unlike the old school small- and big-block Chevy V8 engines , the Kohler K-series and Magnum engine block models K241, M10, K301, M12, K321, M14, K341 and M16 are not all the same. There are several variations in bolt patterns and PTO end flange configurations between these blocks. Before replacing an engine block and if possible, the best thing to do is have the original engine rebuilt, then all the original accessories will attach to the original block with no modifications. But if the original engine block is not rebuildable and damaged beyond repair, another block of the same type (specification number) will need to be acquired. If interested in purchasing a bare block, please email me several detailed, sharp photos of your original engine block taken at all sides so I match it to one I may have in stock. Packaged shipping weight for each bare block is 45 lbs.

The Major Differences Between the K241, M10, K301, M12, K321, M14, K341 and M16 Kohler Engine and Blocks -

• The K241 and M10 blocks have a STD cylinder bore of 3.250" and the stroke is 2.875". All of these blocks have an exhaust valve diameter of 1.125" and the intake is 1.375". Some rare K241 blocks have "K301" embossed on the PTO end. These have a thicker cylinder wall than ordinary K241 blocks.
• The K301 and M12 blocks have a STD cylinder bore of 3.375" and the stroke is 3.250". There are no other major differences between these two blocks. These blocks have the same size valves, and most external parts will interchange. Due to the smaller cubic inch displacement, which lessens the amount of air that enters the engine, theses engines use a Carter or Kohler #26, or Walbro #52 (1.07" throttle bore) carburetor.
• The K321 and M14 blocks have a STD cylinder bore of 3.500' and the stroke is 3.250". There are no other major differences between the K241, M10, K301, M12, K321 or M14 engines. The early K321 blocks have an exhaust valve diameter of 1.125", and the valves in the later K321 blocks are the same diameter, which is 1.375". Some internal, but most external parts on the K241, M10, K301, M12, K321 and M14 engines will interchange, with the exception of the early style K241 cylinder head and size of the carburetor. Due to the larger cubic inch displacement, which increases the amount of air that enters the engine, the K321 and M14 engines use either a larger Carter or Kohler #28 or #30, or Walbro #60 (1.17" or 1.2" throttle bore) carburetor.
• The K341 and M16 blocks have a STD cylinder bore of 3.750" and the stroke is 3.250". There are no other major differences between the K241, M10, K301, M12, K321, M14, K341 or M16 engines, except the valves are the same diameter, 1.375". And the K341 and M16 blocks have 10 cylinder head bolts. Due to the larger cubic inch displacement, which increases the amount of air that enters the engine, the K341 and M16 engines also use a #30 (1.2" throttle bore) carburetor. And most external parts, except the cylinder head and air shields, will interchange with the K241, M10, K301, M12, K321, M14, K341 and M16 engines.

The Major Differences Between the Kohler K-series and Magnum Engine Blocks -

Some Kohler blocks have wide base flanges (for the wide, deep oil pan) and some have a narrow base with no flanges. (These are used on Cub Cadet, Ford, certain John Deere and Wheel Horse garden tractors.) Most Magnum blocks are wide base, and very few are narrow base. The very early K241 10hp blocks have no indentation for installing an upper mount gear starter (mounting bolts are below the starter motor). Also, some of these older blocks with flanges have no holes drilled for converting to a narrow base oil pan. (But holes can be drilled and tapped.) Some blocks have either a drilled or threaded oil dipstick tube hole next to the cylinder, above the crankcase, while others have no hole present. Some blocks have provisions for a starter-side oil dipstick tube, and some don't. Some blocks came with counterbalance gears and some didn't. Some have expansion plugs where balance gear stub shafts can be installed, and although certain blocks have the bosses, some have no holes drilled for the stub shafts. All Kohler Magnum blocks have no provisions for ignition points.

Some blocks have two threaded holes for installing an exhaust pipe flange, and some don't. Some blocks have provisions to install a mechanical fuel pump, and some don't. Some blocks have different bolt patterns on the PTO end, and Gravely blocks have a raised circular flange. (See below.) Some K241 blocks with K301 embossed on the PTO end have a thicker cylinder wall, and some K241 blocks without the K301 embossing have an ordinary thickness cylinder wall. The 12 fin K341 blocks have an ordinary thickness cylinder wall, and the 13 fin K341 blocks have a thicker cylinder wall. Other than all of the before mentioned È, everything else on the Kohler K-series engine blocks are pretty much the same.

The Differences Between the Old Kohler K-series and the Newer Kohler Magnum Engines -

The Magnum engines replaced the K-series in later years. The Magnum engines are basically the same engine as the K-series. The main differences are, besides the baffle shields (sheet metal) that covers the block, the Magnum has solid state ignition, a fixed main jet (Walbro) carburetor and the starter motor fastens to the OEM bearing plate instead of the engine block. And there are no provisions for using ignition points. Most of the external and all the internal parts are interchangeable, and most aftermarket (high performance) parts are interchangeable with either engine.

A Kohler K-series and Magnum M10, M12, M14 and M16 single cylinder engines will fit in place of a Kohler K241 or M10 engine. These all basically have the same external dimensions, with the exception of the 16hp, which has a larger cylinder. Kohler engines are like the old school small block or big block Chevrolet V8 engines . A small block 400 CID engine can be used in place of a 265 CID engine, and a big block 572 CID [crate] engine can be used in place of a 366 CID [truck] engine, because they basically have the same external dimensions. The main difference with Kohler engines is the bolt patterns on the PTO end of the block. Each block is made specifically for the garden tractor, small motorized vehicle or lawn and garden equipment it goes in. When replacing an engine block with another, make sure the bolt pattern matches that of the original block so the PTO accessories, braces and brackets can be bolted on with no modifications.

The Kohler Magnum engine models M10, M12, M14 and M16 can be used in any Cub Cadet garden tractor. The majority of the Magnum 10-16hp single cylinder engines have flanges at the base. Therefore, the block will need to be converted into a narrow base by cutting off the flanges on each side and then cut new threads in the holes in the block for the narrow oil pan. And the other parts that's needed are: a K-series large OEM bearing plate with an upper mount gear starter (mounting bolts are below the starter motor), or a small K-series OEM bearing plate with a starter/generator; a small or large diameter K-series flywheel with a matching flywheel shroud and baffle shields (sheet metal); and being there's no provisions for ignition points and no points lobe on the Magnum camshaft, Kohler's Breakerless Ignition or crank trigger ignition will need to be used.

Only eight models of the 10-16hp Kohler Magnum single cylinder cast iron block engines was manufactured as a narrow base. The specification numbers for these are as follows: M10, specification #'s 461509, 461534 (Cub Cadet garden tractor model 1050); M12, specification #'s 471512, 471514, 471570 (Cub Cadet garden tractor model 1210); M14, specification #'s 601512, 601513; and M16, specification # 711536. All other 10-16hp Magnum engine block specification numbers are a wide base.

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Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website.

Convert Kohler engine model K241, M10, K301, M12, K321, M14, K341, M16 or K361 wide base/flanged block to narrow base for use in a garden tractor requiring a narrow base engine block and oil pan. (Cub Cadet, Ford, John Deere, Wheel Horse, etc.) Cut off flanges even with sides of block, weld-in steel stock to fill-in oil fill/level check openings (notches), and cut new threads for narrow base oil pan mounting holes. $100.00 labor, plus return shipping with FedEx Ground.

Any Kohler Magnum single cylinder 10-16hp engine would be excellent to pull with. The only problem is, being these come with solid state ignition, with no provision for ignition points, if a steel flywheel is going to be used, a flywheel-triggered or crank trigger ignition system must be needed, too. Also, if the engine has counterbalance gears, they will definitely need to be removed because one or the other could break, destroying the block and other parts. For most engines, it does absolutely no good to reinstall them. Most Kohler engines don't come with them and in most engines, they do very little to reduce engine vibration. When left out, the engine should not vibrate more than usual. Being balance gears are made of cast iron material and operate [out of balance] on a single, narrow needle bearing for support, they've been known to break and destroy the crankshaft, camshaft and engine block. I've seen this happen to a good engine a few times. Therefore, I highly recommend leaving them out. But if the engine vibrates excessively with the absence of the balance gears, the flywheel and/or crankshaft will need to be dynamically and precision spin-balanced to reduce engine vibration. Click or tap here to learn more about flywheel and/or crankshaft balancing.

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How to Convert a Single Cylinder Kohler K-Series Engine into a Magnum Engine -

To convert the Kohler K-series K241, K301, K321 or K341 engine into a Magnum M10, M12, M14 or M16 engine, the parts that's needed are: Magnum OEM bearing plate; starter motor (the support brackets for the starter are for mounting of the starter solenoid only. They do not support the starter motor whatsoever); flywheel (w/external magnet); plastic cooling fan assembly; flywheel shroud; solid state ignition coil w/mounting screws; plastic inner air baffle; cylinder head (cover) and cylinder (side) baffles (sheet metal). The only difference in these baffles is the M10, M12 and M14 all share the same baffles over the cylinder head and on the cylinder, and the M16 use different (larger) baffles. The Kohler points pushrod hole will also need to be plugged with a Briggs & Stratton points plunger plug. And when installing the bearing plate, the cam pin hole will need to be sealed with clear RTV silicone adhesive sealant because the Magnum bearing plate will not cover the hole. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of clear RTV silicone adhesive sealant makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.

FYI - Solid state ignition provides a more stable ignition timing than points ignition. The ignition timing for a K-series engine is less stable because the points operate off the camshaft, which has a tendency to "move around" a few thousandths of an inch while the engine is running, which effects the ignition timing. Flywheel-triggered ignition timing, such as the Magnum solid state ignition, is more stable because it operates off the crankshaft, which doesn't "move around" as much as the camshaft. One thing is lessened and another is gained with either ignition system. [Return To Previous Paragraph, Section or Website]

How to Determine the Condition of an Engine That Smokes A Lot Out the Exhaust -

The best way I found to determine if a small engine needs rebuilding is to remove the cylinder head(s), and look at the condition of the head gasket(s). If there's signs of oil leakage between the pushrod area (OHV models and V-twins), this means the head(s) are warped and needs to be resurfaced on a wide, flat belt- or disc-sander/grinder to remove the any warpage and restore flatness. Resurfacing the cylinder heads on a sander/grinder to remove any warpage and restore flatness works best. Because if only new head gaskets are installed, the possibly of a leaking head gasket still exist. Once the heads are properly resurfaced, new gaskets installed and the head bolts are torqued to specs, the heads should not warp and leak again. Also, look at the top edge of the piston(s). If the carbon deposits is washed off and there's oil on top of the pistons, then this means the piston and rings are worn. And run the piston(s) down in the cylinder and look and feel with your fingers for any scratches or score lines on the cylinder walls. If there are scratches or score lines and they're deep (enough to catch your fingernail on), the cylinder(s) will need to be bored to the next oversize and new matching oversize piston and rings will need to be installed.

BUYER BEWARE! A word of caution before purchasing a used or [supposedly] rebuilt engine: Remove the cylinder head and oil pan (they're easy to remove), and then inspect the internal parts for damage and/or excessive wear. If the seller refuse to allow the engine to be internally examined, then perhaps it'll be best not to purchase it. Because once the seller has your money, all you might have is some scrap metal on your hands.

Detailed Information About the Kohler Engine Models KT17 (first design), KT19 (first design), KT21, and KT17 Series II and KT19 Series II Oiling Systems - Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II and KT21 all have a gear-driven gerotor oil pump, and use one of two types of pressurized lubrication systems. NOTE: The KT21 was a short-production engine, and although certain parts off of the other twin cylinder engines will fit this engine, most parts for this engine are no longer available from Kohler. [Top of Page]

The KT17 (first design), KT19 (first design) and KT21 engines use a pressurized SPRAY lubrication system. The oil pump delivers oil to the main bearings and camshaft bearings at approximately 5 PSI. The main bearings are under pressurized oil, but lubrication for the connecting rods and journals is provided by oil sprayed continuously from two small holes drilled in the camshaft in alignment with the connecting rods.

On the other hand, the redesigned KT17 Series II and KT19 Series II (including all Magnum opposed twin cylinder engines) have a full pressure lubrication system, much like in a modern-day automobile engine. The Full Pressure Lubrication System delivers oil to the crankshaft bearings, camshaft journals, and connecting rod journals at approximately 25-50 PSI. A spring-loaded pressure relief valve, located in the engine crankcase, behind the closure plate, regulates and limits the maximum oil pressure in the system. The twin cylinder Series II and all twin cylinder Magnum engines have a spring-loaded pressure relief check valve (steel ball with a pressure relief spring) to regulate the oil pressure, and the KT17 (first design), KT19 (first design) and KT21 engines do not. The Series II and Magnum crankshaft is cross-drilled for oil passages from the main journals to the connecting rod journals, and both the main bearings and connecting rod bearing surfaces receive full lubrication from an oil passageway in the block through the crankshaft. Oil does not spray out of the camshaft onto the connecting rods in the KT17 Series II, KT19 Series II and all Magnum opposed twin cylinder engines. If there's no oil filter adapter with no oil filter on a KT17 Series II, KT19 Series II or any Magnum opposed twin cylinder engine (oil filter adapter port blocked-off), it's still important to change the oil on a regular basis with these engines, too. Again, fresh, clean oil cost less than another engine or an engine rebuild.

The crankcase oil in models KT17 (first design), KT19 (first design), KT17 Series II, KT19 Series II, MV16, M18, MV18, M20 and MV20 without an oil filter should be changed every 25 hours of run time. For the average homeowner, this is about once a year. But the oil in models KT17 Series II, KT19 Series II, MV16, M18, MV18, M20 and MV20 with an oil filter adapter and oil filter should be changed every 50 hours of run time, which on the average, is about every two years, and the oil filter can be changed every other oil change.

The Kohler KT17 (first design) and KT19 (first design) engines are well-designed and well-built engines, but have gained a bad reputation because the crankcase oil was not changed on a regular basis or at all, the wrong velocity of oil was used and/or the engine was ran low on oil on the side of a hill. (Virtually any engine can have a bad reputation if the oil isn't changed.) There's also a wide-spread rumor that these engines have the oil pickup strainer housing located off to one side in the bottom crankcase. This supposedly caused the oil pump not be able to pick up oil on the side of a hill more than a 30º angle/slope with the crankcase full of oil, which resulted in insufficient oil delivery/lubrication to the crankshaft and through the camshaft spray holes that cause the number one connecting rod to either burn or break. However, this is NOT true! What causes the rod failure mostly is the crankcase oil not changed on a regular basis, or at all. (Any KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18 or M20 without an oil filter with a lot of hours of use that is still in service today have obviously been well maintained by caring and responsible person(s) throughout the years.)

If the wrong velocity of oil is used, or if the main bearings are worn due to the oil not being changed, this will lower the oil pressure in the camshaft, and the pressurized spray lubrication system will cause insufficient oiling to the connecting rod journals, especially the #1 connecting rod/journal, which is closest to the flywheel, receives less oil than the #2 rod/journal with worn main bearings, which will eventually lead to connecting rod failure. Being there's no oil filter for these engines, normal metallic wear fragments in the oil grind away at the crankshaft main journals and main bearings, especially the rear main and journal because the moving part wears more than the stationary part. The wear amount increases the oil clearance between the journal and bearing (oil clearance should be .0013" minimum to .0033" maximum), resulting in excessive oil drainback into the sump and providing insufficient oil pressure and flow through the camshaft (again, there is about 5 PSI oil pressure in these engines), which allows less oil sprayed on the connecting rods to lubricate them. This is why the design was changed to a full pressure lubrication system as explained below Ê. When rebuilding either engine, the crankshaft main journals (and perhaps rod journals, too) should be reground if worn beyond OEM Kohler specifications and new undersize main bearings should be installed. The rod journals can only be reground to .010" undersize, and .010" undersize rods will need to be used. In most cases, it's cost-prohibitive to have a worn or heavily scored crank journal welded up and reground back to STD size. Also, on these engines, if one main journal (mostly likely the PTO end) is worn beyond specs, it can be reground undersize (.010" or .020"), and a new matching undersize main bearing will need to be used, and if the other main journal (most likely the flywheel end) measures within specs, it can remain STD size.

The crankcase halves for the KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20 engines have the same dimensions, except there's no provision (port) for mounting an oil filter adapter on the KT17 (first design) and KT19 (first design) engines. The reason Kohler didn't provide a provision for use of an oil filter is because again, these engines produce only about 5 PSI oil pressure, and being there's no oil by-pass in the oil filter, there wouldn't be enough pressure to pump the oil through the filter and then to the main bearings and spray enough oil on the rods and journals, especially when the engine (oil) is cold. Therefore, being there's no provision on the engine block for an oil filter to filter out contaminants from the crankcase oil, it'll be a good idea to install either a magnetic oil drain plug, or glue a very strong rare earth/neodymium magnet to the inside bottom of the crankcase to attract metallic steel or cast iron wear fragments for continued full oil pressure and longer engine life. Sometimes some of the wear fragments do not drain out with the oil when performing an oil change, even when the oil is hot. The crankcase oil should be changed once a year or every 25 hours of run time. Be sure to use high quality 10W30 or 10W40 motor oil, too. The KT17 and KT19 (first design) are very good engines and should last a long time, only if high detergent motor oil is used, and the crankcase oil is changed on a regular basis and/or using non-detergent motor oil! Fresh high detergent motor oil containing a high zinc content anti-wear additive, such as ZDDP (Zinc dithiophosphate) is cheaper than a new engine or an engine rebuild. The engine, transmission, transaxle or gearbox will last much longer with uncontaminated and cleaner oil. Remember - metal flake looks good in paint, not in oil.

The port shown in the photo to the right ->, which is located next to the oil dipstick tube, is in alignment with the oil galley, and on models KT17 Series II, KT19 Series II, M18 and M20, can be used with a low oil shut-off sensor, oil pressure switch or a 50 PSI oil pressure gauge. But for models KT17 (first design), KT19 (first design) and KT21 engines, only a 5 PSI oil pressure gauge can be used to monitor the oil pressure. Because at only 5 PSI of oil pressure, using a low oil shut-off sensor or oil pressure switch may prevent the engine from starting.

Something to ponder - The crankshaft and camshaft out of a Kohler KT17 (first design), KT19 (first design) engine can be used in a Kohler Magnum M18 crankcase with the KT17 (first design) crankshaft and camshaft, or the KT19 (first design) connecting rods, crankshaft and camshaft can be used in a M20 crankcase. The "hybrid" engine combination of parts will undoubtedly have much higher oil pressure to spray more oil on the connecting rod journals, and it can have an oil filter adapter, for longer engine life.

How to Use a Kohler KT17 Series II, KT19 Series II, Magnum M18 or M20 Crankshaft in a Kohler KT17 (first design) or KT19 (first design) Engine -

If the journals on a Kohler KT17 (first design) or KT19 (first design) crankshaft are burnt or worn down beyond (re)use and when a replacement KT17 (first design) or KT19 (first design) crankshaft that's in good, reusable/rebuildable condition cannot be found, the crankshaft out of a KT17 Series II or Magnum M18 (for the KT17 first design engine), or the crankshaft out of a KT19 Series II or Magnum M20 (for the KT19 first design engine) can be used instead. The connecting rods (with the bigger ends) from the KT19 Series II or M20 will also need to be used in the KT19 first design engine.

Anyway, to use a Magnum M18 or M20 crankshaft in a Kohler KT17 (first design) or KT19 (first design) engine, for the Magnum crankshaft, the drilled oil galley passageway in the PTO end main journal will need to be plugged to maintain adequate oil pressure through the camshaft so sufficient amount of oil can be sprayed on both connecting rods and journals, and be supplied to the flywheel end main journal. There's no need to plug the oil galley passageway in the flywheel end main journal of the crankshaft because with the PTO end main journal oil galley passageway plugged, sufficient amount of oil will be able to reach the flywheel end main journal through the camshaft and oil passageway and to lubricate the flywheel end main journal. Actually, with the flywheel end oil passageway open, if there's enough oil pressure and supply, the open passageway will help provide extra lubrication to the #1 rod.

Failure to plug the PTO end main journal oil galley passageway will allow the majority of oil travel through the PTO end main journal oil galley passageway to the #2 rod/journal, and an insufficient amount of oil will not travel through the camshaft and be sprayed on the #1 rod/journal and supplied to the flywheel end main journal through the camshaft.

There are two ways to plug the PTO end main journal oil galley passageway in the crankshaft...

• Weld up the oil passageway on the main journal and then grind away any protruding part of the weld flush with the journal so it won't make contact with the main bearing.
• Cut shallow threads in the oil passageway on the main journal with a 12-24 UNC high speed steel TAPER hand tap (gently use a TAPER tap for much easier cutting of threads into the surface-hardened journal) and tighten a 12-24 UNC x 3/16" length Allen (hex head) set screw in the threaded hole secured with high strength liquid threadlocker (Red Loctite or Permatex). And then grind away any protruding part of the set screw flush with the journal so it won't make contact with the main bearing.

FYI - I have performed the above with several of my customer's KT17 first design and KT19 first design engine rebuilds with a replacement KT17 Series II or M18 crankshaft, or a KT19 Series II or M20 crankshaft of the same dimensions (that's in good condition) when a first design crankshaft of the same dimensions isn't available, and it works great!

And being the Kohler Magnum MV16, MV18 and MV20 vertical shaft engine crankshafts have a much longer PTO end, these would be impractical for use in a horizontal shaft engine, unless the PTO end is machined shorter for use with the horizontal shaft engine's particular application.

The KT17 and KT19 (first design), and the KT17 Series II and KT19 Series II engines look pretty much the same on the outside, except the KT17 and KT19 (first design) engine blocks have no provision (port) for an oil filter and no port to connect an oil pressure light or mechanical oil gauge. Another way to tell which engine is which (without completely disassembling the engine to see the crankshaft and camshaft for oil holes) is by the engine specification numbers. The specification numbers follows the engine model number on the affixed sticker or label. The specification numbers for the KT17 (first design) engines are 24299 and lower. The specification numbers for the KT17 Series II engines are 24300 and higher. The specification numbers for the KT19 first design are 49199 and lower. The specification numbers for the KT19 Series II are 49200 and higher. KT21 engines - All specification numbers (32120-32148).

The Differences Between the Barrels/Cylinders/Jugs on Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, MV16, M18, MV18, M20 and MV20 are...

• The KT17 (first design) and KT19 (first design) barrels/cylinders/jugs do not have the bosses to mount a bracket for the [Magnum] solid state ignition coil.
• The KT17 Series II and KT19 Series II barrels/cylinders/jugs do have the bosses to mount a [Magnum] solid state ignition coil, but are not drilled and tapped. (The side of the valve spring compartment on the KT17 (first design), KT19 (first design), including the KT17 Series II and KT19 Series II barrels/cylinders/jugs, and the bosses on the KT17 Series II and KT19 Series II barrels/cylinders/jugs can be used for A-1 Miller's custom electronic ignition conversion kit.)
• The KT17 (first design), KT17 Series II, MV16, M18 and MV18 barrels/cylinders/jugs have the same dimensions, and has 10 cooling fins and the two fins closest to the crankcase have curved indentions.
• The KT19 (first design), KT19 Series II, M20 and MV20 barrels/cylinders/jugs have the same dimensions, and has 11 cooling fins and on the two fins closest to the crankcase are flat across.
• The KT17 (first design) and KT19 (first design) barrels/cylinders/jugs have 3/8" mounting holes, and the crankcase halves for these barrels/cylinders/jugs have 3/8" studs and nuts.
• The KT17 Series II, KT19 Series II, MV16, M18, MV18, M20 and MV20 barrels/cylinders/jugs have 5/16" mounting holes, and the crankcase halves for these barrels/cylinders/jugs have 5/16" studs and nuts.
• The KT17 (first design), KT17 Series II, MV16, M18 and MV18 barrels/cylinders/jugs are 5/16" shorter than the KT19 (first design), KT19 Series II, M20 and MV20 barrels/cylinders/jugs, when measured from the crankcase mounting surface to the head gasket surface, because the KT19 (first design), KT19 Series II, M20 and MV20 engines have a 5/16" longer crankshaft stroke.
• The valves in the KT17 (first design), KT17 Series II, MV16, M18 and MV18 all have the same dimensions, except for a 30º or 45º valve face/seat angle, but are .285" shorter than the valves in the KT19 (first design), KT19 Series II, M20 and MV20 engines, because the KT17 (first design), KT17 Series II, MV16, M18 and MV18 have a 5/16" shorter crankshaft stroke.
• The valves in the KT19 (first design), KT19 Series II, M20 and MV20 all have the same dimensions, except for a 30º or 45º valve face/seat angle, but are .285" longer than the valves in the KT17 (first design), KT17 Series II, MV16, M18 and MV18 engines, because the KT19 (first design), KT19 Series II, M20 and MV20 have a 5/16" longer crankshaft stroke.
• The exposed/extended part of the cylinder walls on the KT17 (first design), KT17 Series II, MV16, M18 and MV18 are curved, and the exposed/extended part of the cylinder walls on the KT19 (first design), KT19 Series II, M20 and MV20 are flat.
• The barrels/cylinders/jugs for the KT17 (first design), KT17 Series II, MV16, M18 and MV18 engines cannot be used on the KT19 (first design), KT19 Series II, M20 and MV20 engines, and vice-versa.
• One of the barrels/cylinders/jugs off of a KT17 (first design) engine can be used on a KT17 Series II, MV16, M18 or MV18 only for the #2 cylinder. And one of the barrels/cylinders/jugs off of a KT19 (first design) engine can be used on a KT19 Series II, M20 or MV20 only for the #2 cylinder. This is the cylinder on the left side of the engine when facing the flywheel. The (first design) engine barrels/cylinders/jugs have 3/8" mounting holes, and the Series II and Magnum engine barrels/cylinders/jugs have 5/16" mounting holes. If using a first design cylinder on a Series II or Magnum engine, two reducers/spacers, 5/16" I.D. x 3/8" O.D., must be installed on opposite sides of the cylinder, so the centerline of the cylinder wall will be centered with the centerline of the main bearings on the crankshaft to prevent binding of and wear to the wrist pin and/or connecting rod journal.
• The sheet metal (flywheel shroud, baffles and cylinder shrouding) will interchange between the KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, MV16, M18, MV18, M20 and MV20 engines.
• Click here to install electronic ignition on the KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II engines.

Advertisement: | Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

Oil Level Check and Drain Plugs with Tapered Threads and Square Head listed below. A-1 Miller's oil drain plugs have a super strong rare earth/neodymium magnet. Five times stronger than competitor's ceramic (ferrite) magnet and resists demagnetization. Plugs listed below can be used on various other makes and models of transmissions, transaxles, gearboxes and small engine crankcases. Tapered threads requires no sealing gasket or sealant, and threads will not strip out when tightened. To avoid cracking oil pan, do not over-tighten! When in doubt, use plumber's thread sealing tape to insure proper sealing of threads to prevent a possible oil leak. Universal application. Magnet attracts and removes ferrous metallic wear fragments from the motor oil or transmission/gearbox to reduce engine or gear/bearing wear. Sometimes some of the ferrous wear fragments settle to the bottom of the oil pan and do not drain out with the oil when performing an oil change, even when the oil is hot. Magnetic drain plugs are suitable for engines with splash oil lubrication (no oil pump/filter). The engine, transmission, transaxle or gearbox will last much longer with uncontaminated and cleaner oil. Remember - metal flake looks good in paint, not in oil. FYI - If you don't know or can't find any information on the maximum oil quantity for any specific gear drive transmission, transaxle, right angle gearbox, or garden tiller sealed chaincase or gearbox, well, the unit in question is full when oil runs out of the oil level check/fill plug hole that's located halfway [of the drive axles or lower output shaft(s)] on the side(s), front or rear of the unit. All of these fill this way. When the unit is in motion, the lower gears in a transmission or transaxle picks up the oil and slings it on the upper gears, shafts and bearings to lubricate them. And in automotive rear ends, the ring gear picks up the oil and slings it on the pinion gear, spider gears, shafts and bearings to lubricate them. Due to high friction between the gear teeth in transmissions, transaxles, right angle gearboxes and garden tiller gearboxes, or an "open" (non-locking, free-spinning) rear end or in an automotive rear end with a Detroit Locker, SAE 90 weight gear oil must be used. But in an automotive Posi-Trac limited-slip differential, SAE 90W140 weight gear oil must be used to prevent chattering of the locking clutches going around turns. And due to much less friction of roller chain(s) on sprocket teeth in a sealed chaincase, 10W30, 10W40 or SAE 30 weight heavy duty motor oil can be safely used. In front-wheel-drive vehicles, the differential is typically built into the transmission or transaxle, and shares the same transmission fluid, rather it be SAE 90 weight gear oil for a manual shift transmission or ATF for an automatic transmission. 1/8" NPT Oil Level and Drain Plugs. (0.405" O.D. tapered threads.) All MTD-built Cub Cadet garden tractor aluminum housing creeper drive units are packed with grease from the factory. Therefore, for better lubrication and less wear inside the creeper drive unit, install ordinary plug on opposite side of unit of shifter to serve as an oil level check, and install magnetic plug on bottom of unit to attractive metallic wear fragments and drain/change the oil. Entire creeper unit must be completely disassembled and cleaned, a hole drilled midway on the side, another hole drilled on the bottom, and both holes will need to be threaded with an 1/8" NPT hand tap for the plugs. Then fill unit through the breather opening with SAE 90 weight gear oil. $8.00 for both plugs, plus shipping & handling. 1/4" NPT Magnetic Oil Drain Plug. (0.540" O.D. tapered threads.) Fits various Briggs & Stratton, Kohler, Tecumseh, and various other makes and models of small engines. A-1 Miller's part. Replaces discontinued Kohler part # X-75-2. $5.00 each, plus shipping & handling. 3/8" NPT Magnetic Oil Drain Plugs. (0.675" O.D. tapered threads.) Fits various Briggs & Stratton, Kohler, Tecumseh, and various other makes and models of small engines. A-1 Miller's part. Replaces Kohler part # X-305-4-S. $5.00 each, plus shipping & handling. OEM Kohler part # X-305-4-S. $18.35 each, plus shipping & handling. 1/2" NPT Magnetic Oil Drain Plug. (0.840" O.D. tapered threads.) Fits side of oil pan on Kohler engine models K141, K160/K161, K181, L160/L161, L181 and M8 engines, and oil drain on Cub Cadet garden tractor transaxles, various automotive manual shift transmissions, and various other makes and models of small engines. A-1 Miller's part. Not available from Kohler. $5.00 each, plus shipping & handling. 3/4" NPT Magnetic Oil Drain Plug. (1.050" O.D. tapered threads.) Fits various Briggs & Stratton, Kohler, Tecumseh, and various other makes and models of small engines. A-1 Miller's part. Not available from Kohler. $5.00 each, plus shipping & handling. 5/8" I.D. Fiber Sealing Gasket. Fits OEM Kohler 3/8" NPT Oil Drain Plug with Hex Head. Replaces discontinued Kohler part # 241063. $1.00 each, plus shipping & handling. 3/4-10 UNC (Straight Threads) Magnetic Oil Drain Plug. Use to replace OEM Kohler 3/8" NPT oil drain plug with stripped threads in [aluminum] oil pan. Includes fiber sealing gasket. NOTE: Threads in oil pan must be enlarged with a 3/4-10 UNC hand tap. A-1 Miller's part. $5.00 each, plus shipping & handling.

How to Convert Kohler Engine Models MV18 or MV20 Vertical Shaft Engines into Models M18 or M20 Horizontal Shaft Engines -

The Kohler engine models MV18 or MV20 vertical shaft can be easily converted into models M18 or M20 horizontal shaft. To make this happen, the oil pickup hole on the oil pump side of the MV18 or MV20 crankcase will need to be tapped for threads and plugged with an Allen pipe plug or a short bolt with sealant. The parts needed are of a KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, M18, M20, and perhaps KT21: intake manifold, closure plate (to replace the oil sump cover), oil pickup tube with the strainer, throttle/governor linkage, air cleaner adapter, oil dipstick assembly, and oil filler tube or plug.

By the way - there are 53 variations of the model KT17 engines, 52 variations of the model KT17 Series II engines, 15 variations of the model KT19 engines, 36 variations of the model KT19 Series II, 5 variations of the model KT21 engines, 169 variations of the model M18, 50 variations of the model MV18, 112 variations of the model M20, and 21 variations of the model MV20. The variations are the differences between engine models that was manufactured by Kohler.

FYI - Some people confuse a vertical shaft engine with a horizontal shaft engine, and vice-verse. They think being the piston travels vertically (side to side ó) or horizontally (up and down ô), that it's a vertical or horizontal engine. But it's the position of the crankshaft that determines if it's a vertical or horizontal shaft engine. This is why they're called vertical SHAFT and horizontal SHAFT. Otherwise, they would be called a vertical piston engine and horizontal piston engine, which is the wrong terminology.

How to Convert a Briggs & Stratton Opposed Flathead Twin Cylinder Vertical Shaft Engine into a Horizontal Shaft Engine -

FYI - Some people confuse a vertical shaft engine with a horizontal shaft engine, and vice-verse. They think being the piston travels vertically (side to side ó) or horizontally (up and down ô), that it's a vertical or horizontal shaft engine. But it's the position of the crankshaft that determines if it's a vertical or horizontal shaft engine. This is why they're called a vertical SHAFT engine and horizontal SHAFT engine. Otherwise, they would be called a vertical piston engine and horizontal piston engine, which is the wrong terminology. Anyway, the parts needed to convert a vertical shaft opposed twin cylinder flathead B&S engine into a horizontal shaft model are as follows. The parts listed below Ê must come off a horizontal shaft opposed twin cylinder flathead B&S engine.

• Acquire an oil pan off a horizontal shaft engine (to replace the side cover).
• Acquire an oil dipstick and tube off a horizontal shaft engine.
• Acquire a side cover off a horizontal shaft engine (to replace the oil sump cover).
• Acquire an intake manifold, carburetor and governor linkage off of a horizontal shaft engine.
• Install a steel oil dipper on each connecting rod to lubricate internal parts.
• Drill oil drain-back holes in the block for the camshaft and crankshaft bearings so the oil will lubricate these vital moving parts and drain back down in the oil pan.
• Everything else on the engine should work with no modifications. The PTO end of the crankshaft will be a little long, being it's made for a vertical shaft engine. But it'll still work just fine in the horizontal position.

To install a opposed twin cylinder engine into a Cub Cadet garden tractor, on the narrow and wide frame Cubs, the frame rails will need to be cut down for installation of an opposed twin cylinder engine. But the spread frame Cubs are made for the opposed twin cylinder engine. And a V-twin engine will fit in virtually into any Cub Cadet garden tractor with few modifications. The frame rails shouldn't have to be altered either. Go here for an example of a V-twin that was installed in a wide frame Cub Cadet garden tractor: http://www.smallenginewarehouse.com/RepowerItems.asp?Brand=Cub%20Cadet&Model=1000.

How to Reinforce OEM OHV V-Twin Aluminum Block Engines to Prevent from Cracking or Breaking for High Performance/Open RPM Competition Pulling - [Top of Page]

A Kohler, Kawasaki, etc., V-twin engine with a 2-barrel carburetor with separate/individual intake runners, one barrel can lean out due to a partially clogged main jet, while the other barrel will provide plenty of fuel to the cylinder. The cylinder with the partially clogged jet will run hotter than normal, which can cause the piston rings to lose their expansion against the cylinder wall. The cylinder head can also warp and valve seats can loosen and fall out of their counterbore. This is why most pullers prefer to use a single barrel carburetor.

Also, most OEM OHV V-twin aluminum engine blocks will "bend and twist" just a few thousands of an inch when hot and under competition pulling stress and strain. This cause them to lose valuable compression because the valves become unseated and the piston rings lose partial contact against the cylinder wall. Not to mention the main radial ball bearings are also put into a bind on the crankshaft when under the stress and strain of pulling. Click the photo below to see what can happen to a Kohler (117hp) Command V-twin engine when used for pulling. [The Brute Pulling and Breaking - YouTube] (Watch the video to the end.)

When building an OEM aluminum block V-twin engine for competition pulling, and to prevent the crankcase and/or closure plate from cracking or breaking under severe strain, do not install a gasket between the crankcase and closure plate (end cover)! Instead, apply a thin bead of clear RTV silicone adhesive sealant between the crankcase and closure plate, then tighten the bolts to the factory recommended torque value. The absence of the gasket will allow for direct metal-to-metal contact, which keeps the fastening bolts securely tight and this strengthens/reinforces the crankcase and closure plate to prevent it/them from cracking or breaking when under severe strain, with the silicone filling in any irregularities or imperfections between the two metals, eliminating oil leaks. This is the same reason an oil pan gasket is not recommended for a single cylinder K-series and Magnum competition pulling engine. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. When applied sparingly, it can't be easily seen or noticed between the parts.

Referring to the photos below Ê, what caused the closure plate (end cover) and crankshaft to break is because a gasket was used between the crankcase (engine block) and closure plate. The bolts securing the closure plate to the crankcase made the closure plate totally dependent on the bolts only for rigidity, and the gasket acted as a cushion. When the high RPM/high compression engine was under severe pulling stress, this placed tremendous amount of strain and movement of the closure plate. The gasket allowed the closure plate to "move around" a few thousandths of an inch against the bolts independently of the crankcase. When the crankcase and closure plate were "moving around" against each other, this caused the gasket to "flatten out" and become thinner, which allowed the bolts to loosen slightly. The bolts did not rotate counterclockwise to loosen, they simply lost their torque or "tightness" against the metal. If no gasket was used, and a thin bead of clear RTV silicone adhesive sealant was applied between the crankcase and closure plate (and the necessary thrust washers and shims installed to control the crankshaft and camshaft clearance/end-play), and the bolts torqued to specs, the closure plate would have had metal to metal contact and became more or less "integrated" with the crankcase (with the silicone to seal the irregularities or imperfections between the two mating surfaces), this would have allowed the closure plate to be much more rigid and less prone to breakage. Some non-professional/amateur engine builders are die-hard believers in the use of gaskets for the entire engine, and this is the ultimate result in their way of thinking.

Cast iron engine blocks on the other hand hold their shape a lot better when hot and under stress. Aluminum engines work best for conditions that doesn't place them in a lot of stress. Such as ATVs, racing go-karts, racing lawn mowers, etc. Because there's fresh air moving over the engine, keeping the metal cool, and the block isn't being strained by the vehicle pulling a heavy load. This is why the cast iron block Kohler engines work best for competition pulling. We think that Kohler is the best engine for pulling. They're the old school "Chevrolet" of competition pulling engines (you know what I mean ). Because cast iron is able to "hold its shape," handle high operating temperatures, severe stress, high compression and at open RPM. This is why most riding mowers, lawn tractors and lawn and garden tractors have an aluminum block engine. And most garden tractors have a cast iron block engine.

In addition, on the cast iron block single cylinder Briggs & Stratton and Tecumseh engines, the valve stems are parallel to the cylinder. This means that the valve heads set further away from the piston. And in the cast iron block single cylinder Kohler engines, the valve heads set closer to the piston (valve stems and lifters are angled 4°). Therefore, the other engines can't build up as much compression as Kohler engines can. Plus, they can't flow as much air in and out of the combustion chamber at open RPM, like Kohler engines can.

If the crankcase is building up too much air pressure in an OHV aluminum block engine, and blowing oil out the crankcase breather, then chances are, the cylinder heads are warped. This is a common thing with virtually all seasoned OHV aluminum block engines. The heads become warped between the pushrods because there's no head bolt there to apply pressure against the head gasket. To fix the warped heads, remove the heads, resurface them on a wide, flat belt- or disc-sander/grinder to remove the any warpage and restore flatness. Be sure to clean the metal fragments from the heads, deburr the edge of the combustion chamber to prevent any hot spots, install the heads with new head gaskets, torque the head bolts to specs, and readjust the valves. Being the metal has already taken shape from normal engine heat for the first time, the heads should not warp again for the life of the engine.

How to Use Two Engines in a Competition Garden Pulling Tractor -

The alternative to using a V-twin engine in a Cub Cadet competition garden pulling tractor is to use two light-weight aluminum block horizontal shaft single cylinder engines installed side by side with the flywheels facing forward instead. The frame of the tractor would need to be modified and heavily reinforced to support the engines, too. With two engines installed inline, one behind the other with the flywheel on each engine facing forward, with the crankshafts direct-coupled together, it'll be better to use the 31-15.15x15 pulling tires for more weight distribution for better traction. If the engines are installed reversed, the rear end carrier/ring gear in the transaxle would need to be "flipped" so the tractor will drive forward in the forward gears. The reason it'll be better for the engines to be side by side is because less weight will be on the front of the tractor, and more weight will be transferred to the rear tires when pulling for netter traction. For the side by side engines to drive the tractor, a heavy duty centrifugal clutch (with #40 sprocket teeth) would need to be installed on each engine crankshaft, with two #40 sprockets, one offset of the other, installed on the driveshaft, which will act as a mainshaft. Pillow block bearings will need to be used to support the driveshaft. The OEM-type of Cub Cadet garden tractor clutch setup cannot be used. The centrifugal clutches will act like a stall torque converter, much like in an automotive automatic transmission. The centrifugal clutches will engage around 2,000 RPM, and will lock up above 2,600 RPM more or less. The centrifugal clutches will disengage at idling speed (1,200 RPM [±75 RPM]), and the carburetors can be easily adjusted or synchronized without one running engine interfering with the other, unlike in a "direct-coupled together" configuration.

How to Convert the Kohler Command Pro V-Twin Vertical Shaft Engine into a Horizontal Shaft Engine -

The parts needed to convert a Kohler Command Pro V-Twin vertical shaft engine into a horizontal shaft engine are as follows. The parts listed below Ê must come off a horizontal shaft Kohler Command Pro V-Twin engine.

• Drill the oil drain-back holes in the corners of the cylinder heads near the valve train so the oil can drain back down in the oil pan.
• The oil pump must be changed (pickup tubes are different).
• The vertical shaft engine has no horizontal mounting holes on the block. (They are on the sump cover.) So a couple of L-shaped engine mounting plates must be fabricated to convert the block into a horizontal shaft and mount the engine in the tractor frame.
• Various holes in the block must be blocked-off (drain holes are different, etc).
• The intake manifold, carburetor and throttle/governor linkage will also need to be swapped. FYI - Piano wire, which is very hard steel solid wire, can be used to replace most OEM throttle/governor links. Usually .080" / 5/64" is the most common size. A torch will be needed to make the "Z" bend at each end. Actually, it can be used for a lot of different things. Just because it's called "piano wire", don't mean it's for pianos only. Piano wire is available at most Ace Hardware stores.
• Everything else on the engine should work with no modifications. The PTO end of the crankshaft will be a little long, being it's made for a vertical shaft engine. But it'll still work just fine in the horizontal position.

FYI - The big price difference in horizontal vs vertical shaft engines is based on supply and demand. Equipment that require a vertical shaft engine are more plentiful, such as lawn mowers, riding mowers, etc. Therefore, whenever small engine equipment use a vertical shaft engine, this brings down the cost of production of the engine. Equipment that require a horizontal shaft engine are rare (nowadays). Therefore, the price on these engines are higher. Some manufacturers convert their products, such as logsplitters, for use with a vertical shaft engine. This allow them to sell their equipment at a lower price, due to the lower cost engine.

When rebuilding any used engine (also known as a "seasoned" engine), especially an aluminum block engine, as the crankcase and cylinder head(s) get hot for the very first time (new engine), they bend, twist and warp a few thousands of an inch due to normal operating heat. This is called block (and related parts) warping. In other words, combustion heat causes the metal to "take shape." This is normal for all new engines, small engines, automotive, etc., gas or diesel, air-cooled or liquid-cooled, and is unavoidable. So when rebuilding a used engine, have the cylinder head and other parts measured with a straight edge. And if they're warped, have them machined flat or resurfaced on a wide, flat belt- or disc-sander/grinder to remove any warpage and restore flatness. This will ensure 100% gasket sealing. And if the cylinder bore(s) are out of round, have them bored to the next oversize to ensure a 100% piston ring seal. When the parts get hot the second time (due to normal operating heat), they should not bend, twist or warp again. This is a one time deal.

How to Determine if an Engine Needs Rebuilding - (This information applies to most small engines, automotive, farm and industrial equipment engines.)

First of all, oil usage is controlled by the "snugness" of the piston in the cylinder or how cool the engine operates. The below Ê are things that can cause an engine to burn oil:

• Over-advanced ignition timing (past the 20° BTDC setting for gas).
• The [adjustable] high speed fuel mixture in the carburetor leaned out too much.
• A fixed high speed main jet Walbro carburetor used and the engine was operated above 3,200 RPM.
• Throttle shaft severely worn in the carburetor, creating a vacuum leak, leaning out the air/fuel mixture.
• Motor oil not changed regularly or too light of viscosity oil is used for warm weather.
• If the engine was ran with an excessively dirty air filter or without a quality air filter under dusty conditions.

Either or a combination of the above È will definitely cause an engine to overheat (except without an air filter), causing the rings to lose their tension against the cylinder wall, resulting in the oil being burned. We have seen all of these things happen to a good engine many times.

If someone tells you that an older cast iron block Kohler engine isn’t worth repairing or rebuilding and repowering your garden tractor small motorized vehicle or small engine equipment with a new engine is the way to go, then they obviously is lying to you, don't know much about older Kohler engines or is trying to make a lot of money by selling you a new repower kit. Most cast iron block Kohler engines will last 30-40 years before they need rebuilding. No small engine made nowadays will last that long. And if they do, chances are they are not worth rebuilding. The old cast iron Kohler engines can be rebuilt multiple times, as long as everything in it is rebuildable and not damaged beyond reuse. We think the older Kohler engines are the old school "Chevrolet" of small engines (you know what I mean ). If you do find an older Kohler engine, despite the condition it's in, just remember that it's worth repairing or rebuilding. It'll be like restoring an old Chevrolet (again, you know what I mean ).

Before the engine is removed from the tractor or equipment and disassembled (this is much easier to do on a platform work table), first, remove the cylinder head and observe the top of the piston. If it's 100% coated with carbon, then the piston rings are in good condition. But if there's oil present and some of the carbon is washed away around the edges, this means that the rings and piston are worn and need replacing, or the cylinder needs to be rebored for installation of a new oversized piston and rings assembly. But if the cylinder is max'd out at .030" and worn, it can be either be bored for an aftermarket (made to OEM specs) .040" oversize piston and rings assembly (OEM Kohler-replicated; only for the K301, M12, K321, M14, K341, M16 and K361 [OHV] engines), or sleeved back to STD size for all other Kohler engines. See my list of STD size, .010", .020", .030" and .040" oversize piston and rings further down in this web site Ê.

The cap on a connecting rod is precision machined (honed) to form an absolute perfect circle to match the rod it is installed on. If a cap is swapped from one rod to another and then installed in an engine, chances are, the rod will be too tight or too loose on the crank journal. If an oil dipper breaks off the cap, another cap can be used on the rod, but the cap (and rod) would need to be precision honed to form a perfect circle again.

Now Move to the Valves. How to Test for Leaking or Burnt Valves - [Top of Page]

The appearance of used valves in an engine are like women, you can't always go by looks. In other words, the appearance of valves in an engine won't tell you if they're sealing in compression 100% or not. A "leak down test" with a gauge will only show you if the combustion chamber has a leak. So the real way to test for leaking valves on virtually any 4-cycle flathead engine, first of all, both valve clearances should be checked and adjusted to specs, if needed, before performing this test. Now with the carburetor, muffler or exhaust pipe and [flathead] cylinder head removed, and with the piston positioned exactly at top dead center (TDC) on the compression stroke (this is when both valves are fully closed), apply Liquid Wrench (spray) or WD-40 around each valve and with a rag/shop towel wrapped around an air blow gun nozzle with the rag/shop towel snug against the port to seal in the air pressure so maximum pressure will be applied to the valves, apply 150± PSI compressed air through the exhaust and intake ports. To perform this same test on an over head valve (OHV) engine, the cylinder head will need to be removed and [lightly] clamped in a bench vise. Anyway, if multiple bubbles form (slight leakage) and/or if the liquid gets "blown out" around the valves (severe leakage) when applying the air pressure, this means the valves are leaking or burnt and a professional valve job is required. Performing a valve job restores full compression, which will allow the engine to start quicker, idle smoothly, rev up with no hesitation, produce lots of power, and run for a long time without stalling or dying (when the ignition timing and carburetor adjustments are set correctly, too). Do not use soapy water to perform this test because the water content will cause the steel and cast iron to rust if not immediately cleaned off and thoroughly dried. The "bubbles" part of this test won't be accurate with freshly reground valves and seats (fresh valve job) because the valves haven't worn into the seats yet to form a perfect seal. This is known as valve wear-in or more commonly as engine break-in. Click the photo to the right -> to watch how this test is performed on YouTube. By the way - The video shows both valves fully closed with the piston positioned at top dead center (TDC) on the compression stroke. And if you're wondering, the Automatic Compression Release (ACR) only works with the exhaust valve. It doesn't hold the exhaust valve open when the piston is at top dead center (TDC) on the compression stroke. It only works when the piston is traveling about halfway up in the cylinder just before it reaches top dead center (BTDC) on the compression stroke. FYI - If you have a Kohler 7-16hp ACR camshaft that was broke in two by a thrown connecting rod, save the spring off of it. It can be used on another good cam that may not have one. Or if your ACR spring places little or weak pressure against the flyweights/levers, it can be re-bent or reshaped to its original condition to place sufficient tension against the flyweights/levers.

Performing a Compression Test with a Compression Tester or Leak Down Tester -

A compression test shows how much air within the combustion chamber is "squeezed" or "compressed," resulting in the P.S.I. of pressure. But a leak down test shows how long the combustion chamber can sustain air pressure within a period of time. A compression test is performed dynamically with the throttle plate in the wide open position, all spark plugs removed (in a multi-cylinder engine) and the engine cranking over at full speed. But a leak down test is performed statically with the (or each) piston positioned at 0º TDC on the compression stroke and engine not cranking over. On a Kohler engine, with the piston positioned exactly at 0º Top Dead Center (0º TDC) on the compression stroke, the automatic compression release (ACR) mechanism allows the exhaust valve to fully close, then a compression test can be performed with a leak down tester. But the ACR effects a compression test when performed with a compression tester. 0º TDC on the compression stroke is when the piston is at its very top in the cylinder with both valves fully closed. 0º TDC is also when the T mark on the flywheel is aligned exactly with the raised boss on the bearing plate (engines with a gear starter), or with centered of the sight hole on the side of the flywheel shroud or on the rear of the bearing plate (engines with a starter/generator), and the initial alignment can be seen with a flashlight through the sight hole in the OEM bearing plate. But the best way to determine if an engine needs to be rebuilt is to remove the cylinder head and look at the edge of the piston. If the carbon deposits is washed away or partially absent from the top of the piston, this means the piston and rings are worn, and the engine needs to be rebuilt. YouTube video link: Does the length of the hose on a compression tester matter?

How to Perform an Accurate Compression Test with a Compression Tester on a Stock or High Performance Small Engine -

Only the Kohler K-series and Magnum single cylinder engines have a compression release mechanism on the camshaft. And due to their low compression, the Kohler opposed twin cylinder engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20 do not have a compression release, nor do they need one. Anyway, an accurate compression reading can't be performed on an engine with an unaltered OEM camshaft due to the compression release mechanism on one of the cam lobes. Depending on the make and model of engine, the compression release is either a small hump (early B&S, various Tecumseh's, etc.), mechanical lever/pin (newer B&S, Kohler, some Tecumseh, etc.) on one of the camshaft lobes that holds either the intake or exhaust valve open about .050" while the piston is traveling halfway up in the cylinder on the compression stroke, or a tiny hole drilled through the exhaust seat next to the exhaust valve on various very early Tecumseh engines. On OEM camshafts with a working compression release mechanism and if the valve clearances are adjusted to specs, the compression release relieves about half the compression air from the combustion chamber at cranking speed. This is so the engines with fixed advanced ignition timing will start easier. When attempting to start an engine with fixed advanced ignition timing, if the compression release isn't working or if the valve (with the compression release) have too much stem-to-lifter clearance (out of adjustment), the engine will "kick back" every time. "Kick back" occurs when the crankshaft suddenly and violently rebounds or rotates in the opposite direction, which is could bend or break the starter armature shaft or the aluminum starter housing.

On various B&S, Kohler models K90/K91, K141, K160/K161, L160/L161, L181, K181 and M8, some Tecumseh, etc. engines without adjustable lifters, but with an automatic compression release (ACR), there is no way to perform an accurate compression test with a compression tester. All that can be done to test the compression is rotate the flywheel quickly by hand in the opposite direction of normal engine rotation. If it rebounds sharply, the engine has adequate compression.

There are two ways to perform an accurate compression test with a compression tester on the Kohler K-series and Magnum engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361:

• On the 10-16hp engines, back off the adjuster on the lifter for the exhaust valve so the compression release lever won't slightly open the valve.
• On the K361 engine, back off the adjuster on the rocker arm for the exhaust valve so the compression release lever won't slightly open the valve.
• Remove the cam gear cover, dislodge the ends of the tiny (hair-like) actuating spring on the compression release levers to disable the compression release mechanism.
• If the starter motor is capable enough to crank the engine over, the compression test can now be performed with the engine under full compression.

To obtain an accurate compression pressure reading, perform the test with a fully charged battery, a starter that's in good condition and the throttle in the wide open position. Or with pull rope engines, place the throttle in the wide open position. When performing a compression test with a gauge on an air-cooled engine, keep in mind that, depending on how the engine is built, the compression ratio or the compression pressure can vary from one engine to another. It depends on the size of the bore and stroke, the volume of the combustion chamber in the cylinder head, if the camshaft has a compression release or not and how much duration the cam lobes have. If a cam has a compression release mechanism, being approximately half the compression is released from the combustion chamber at cranking speed, the compression reading will be cut approximately in half.

When performing a compression test with a gauge on a Kohler engine in good condition under full compression, stock camshaft and no compression release, the K241 and M10 engines can range from 98 to 150 PSI. On the K301 and M12 engines, it can range from 112 to 170 PSI. On the K321 and M14 engines, it can range from 120 to 190 PSI. And the K341 and M16 engines, it can be from 127 up to 192 PSI. The range of the compression pressures depends on the type of cylinder head used. If the camshaft has a working compression release, it will relieve about half the compression pressure (PSI).

And cranking speeds, a long duration cam will relieve some of the combustion chamber pressure, resulting in a lower than normal reading. The more the duration, the lower the reading. Calculate the reading with the duration of the cam in the engine against the duration of a stock OEM cam. Example: If the compression pressure is 100 PSI, multiple 100 by 285 (duration of cam that's in the engine) and then divide the answer by 223 degrees (duration of a stock OEM cam), which gives 128 PSI.

Now for the engine problem: Air from the leak down test came from inside the crankcase due to the gaps in the piston rings. As the engine warms up, due to friction and combustion heat, the rings expand and the gaps close up. The dark colored oil is from partial incomplete burning of the gas that went past the ring gaps into the crankcase because the engine couldn't reach its normal operating temperature due to bad valves. If an engine has an oil pump with an oil filter adapter and oil filter, the oil gets filtered from dirt and metal fragments, preventing excessive wear to vital moving parts inside the engine, but the oil filter will not filter out the dark colored liquid by-products from incomplete burning of the fuel that's mixed with the oil. The by-products will eventually thin out the oil or lower the viscosity, causing excessive wear to the internal moving parts. I've repaired many engines when the piston rings are in good condition, but the valve faces and seats was warped. After performing a professional valve job, regrinding both valve faces and seats, and setting the correct valve clearances, and perhaps installing new guides, customers told A-1 Miller's that their engine ran better and produce more power than when it was new. With a professional valve job performed and with everything else right on the engine, the engine should start quicker, idle smoother, warm up faster, accelerate to full RPM without hesitation, run at normal operating temperature, and burn the fuel more thoroughly, which will allow the crankcase oil to stay cleaner longer.

To remove the engine from a typical IH Cub Cadet garden tractor, first disconnect the battery negative terminal and disconnect all the wiring from the engine and fuel line if the gas tank is separate from the engine. Then remove the PTO clutch engaging linkage, remove the engine mounting bolts, then slide the engine forward so it'll clear the clutch disc or driveshaft, then lift the engine out of the tractor. This is much easier to do on a platform work table.

Now remove the oil pan and connecting rod cap. Observe the rod cap for scoring or burning. Replace or repair it if necessary. Also, the crankshaft journal may be worn and if it is, it will need to be reground to the next undersize. And have the crank journal measured or "mic'd" with an outside precision micrometer to determine if it's excessively worn. Dial or digital calipers can't measure a crank journal or anything else as accurately as a micrometer can. The micrometer measures more accurately because the beam section don't flex as much. Anyway, if the journal is worn, it can be reground to .010" and a .010" undersize plain aluminum [bearing] surface connecting rod can be used or the original rod can be bored for installation of .010" replaceable bearing inserts. But if the journal needs to be reground to .020" or .030", the rod will need to be bored for installation of matching bearing inserts. The only OEM rods available without a bearing are STD size and .010" undersize.

If the cylinder wall is badly scored or tapered, have it bored to the next oversize. The only pistons available for a stock engine are STD, .010", .020" and .030". But if the cylinder is max'd out at .030" and worn, it can be either be bored for an aftermarket (made to OEM specs) .040" oversize piston and rings assembly (OEM Kohler-replicated; only for the K301, M12, K321, M14, K341, M16 and K361 [OHV] engines), or sleeved back to STD size for all other Kohler engines. See my list of STD size, .010", .020", .030" and .040" oversize piston and rings further down in this web site Ê. But if building an engine for more power, don't have the cylinder bored to a maximum of .030" if it doesn't need it. Because a .030" overbore won't necessarily give an engine more power. Having a longer crankshaft stroke increases the power.

I don't offer any engine rebuild kits for three reasons: 1. There are certain parts included in most kits that is not needed or required for the rebuild; 2. If the cylinder in an engine needs to be bored oversize, most rebuild kits don't come with an oversize piston and rings assembly, and; 3. Most entire engine rebuild kits cost more than if each part that's included in the kits were purchased individually, so the rebuild kit would really be a waste of money. So actually, the best thing to do is completely disassemble your engine, clean all the parts, inspect the valves for burning or being bent, mic the crank journal for wear or scoring, and observe the cylinder wall for wear or scoring to determine which internal engine parts are required for a professional rebuild.

The following basic specialty tools are required to disassemble, reassemble and rebuild a single- or opposed twin-cylinder Kohler engine. Most of these tools are available at auto parts stores and online.
Small engine valve spring compressor Cylinder deglazer (if cylinder does not need to be bored oversize for an oversize piston and ring set) Piston ring compressor Quality-made automotive harmonic balancer puller (to remove the flywheel) Automotive distributor wrench (to remove and fasten cylinder nuts on KT-series and Magnum opposed twin cylinder engines)	Valve lapping tool and valve grinding compound Two different types of torque wrenches that reads in inch- and foot-pounds of torque Feeler gauge set (to set the points gap, valve clearances, camshaft clearance/end-play and crankshaft clearance/end-play) Multimeter [set on Ohms resistance] or test light and two small jumper wires (to statically set the ignition timing) Automotive timing light (to dynamically set the ignition timing)
More sophisticated equipment, tooling and machinery is required to perform specially machine work on certain engine components, such as: boring bar and/or cylinder hone to bore the cylinder oversize, crankshaft grinding machine to regrind the crankshaft journal(s); valve face grinding machine to reground the valve faces; valve seat cutter or grinder set to recut or reground the valve seats; milling machine to bore the connecting rod for installation of replaceable bearing inserts; etc. In most cases, the original valves can be reground. But if the valve(s) are severely worn or the face is burned away (especially the exhaust valve), it will need to be machined and/or replaced with a used valve in good condition or a new valve. A-1 Miller's offers the machine work and the parts required to perform a complete and professional engine rebuild. Most common engine rebuild parts required are: piston and rings, connecting rod, valves, gaskets w/oil seals, carburetor kit and complete tune up kit.

How Replaceable Lead-Coated Bearing Inserts (Rod Bearings) Protect An Engine - [Return to previous paragraph]

Due to the lack of or an insufficient amount of oil in the crankcase, or at open RPM with 100% petroleum oil, an ordinary aluminum bearing surface connecting rod will likely to burn the rod and score the crank journal, and if the engine is ran long enough with a loose rod, the rod will likely break, possibly destroying the engine block. But an engine with lead-coated bearing inserts, if the oil is contaminated with dirt or metal shavings, or if the engine is ran low on oil, out of oil or if the wrong viscosity is used (too thin of oil for warm weather conditions or for high performance use), as the bearing inserts wear, they won't score the crank journal like an ordinary plain aluminum bearing surface rod will.

High RPM bearing inserts are made with three layers of material: an outer steel shell for rigidity, a copper underlayment, and a thin inner layer of lead alloy that makes contact with the crank journal. The lead cushions the extreme pressure and cools the crank journal and rod from excessive heat from high RPM engine operation. (When used with conventional/petroleum motor oil.) The lead also allows for small fragments of metal to become embedded into it to prevent scoring or excessive wear of the crank journal. All lead-coated bearing inserts are considered high performance and can withstand very high RPM, and adds durability and toughness to the connecting rod. These are most commonly used in most applications.

Low RPM (up to 4, 000 RPM) bearing inserts on the other hand, have only two layers: the outer steel shell and an inner aluminum alloy layer/coating that makes contact with the crank journal. This type of bearing inserts for Kohler engines are rare, and should NEVER be used in a open RPM engine because aluminum cannot handle heat as well as lead. Aluminum bearing inserts (used with various newer automotive engine steel rods) are not high performance. Aluminum bearing inserts have no heat-resistant lead coating and when used in a open RPM engine with conventional/petroleum motor oil, and even with the additional .001" oil clearance, the bearing will likely burn on the crank journal, resulting in connecting rod failure, which could damage or destroy the engine block. Therefore, these type of bearing inserts should ONLY be used in a 4,000 RPM governed engine with conventional/petroleum motor oil, or can be used with full synthetic motor oil in a full pressure oil pump lubricating system.

Another low RPM (up to 4,000 RPM) bearing inserts is available in an unmachined .060" undersize. A-1 Miller's have a limited supply of these in stock, and can be bored and finish-honed for use with a .040" or .050" undersize crank journal. The unmachined .060" bearing inserts can be used with a .060" undersize crank journal. This particular bearing inserts don't have the protective inner lead-coating. It has a bronze inner layer, which shouldn't be used in a open RPM competition pulling engine. These type of bearing inserts too, just like the aluminum bearing inserts above, should ONLY be used in a 4,000 RPM governed engine with conventional/petroleum motor oil, or can be used with full synthetic motor oil in a full pressure oil pump lubricating system.

A-1 Miller's Professional Repair Service - Bore YOUR Kohler scored or burnt connecting rod(s) and install replaceable lead-coated STD size, .010", .020", .030" undersize bearing inserts for a matching reground undersize crank journal. No need to purchase a new undersize rod. $65.00 for labor and bearing inserts, plus return shipping. A-1 Miller's professional crankshaft rod journal regrinding service also available.

Instead of boring a new or used connecting rod that has a smooth, undamaged bearing surface for installation of bearing inserts, a rod with a scored or burnt bearing surface can be bored out to make room for bearing inserts.

The alternative to having a crank journal reground undersize and using an undersize connecting rod is if the crank journal isn't deeply scored and badly burnt from lack of lubrication or being over-revved, it can be reground undersize until it's perfectly round again and if the original rod also isn't deeply scored or badly burnt, it can be resized to fit the reground odd-size journal with the factory recommended .0025" oil clearance. This is useful for engines when a new replacement undersize rod is cost-prohibitive or is not available. The rod would still be strong and should last a long time. In most cases, it's cost-prohibitive to have a excessively worn or deeply scored crank journal welded up and reground back to STD size. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break.

To resize the rod so it'll fit to a few thousands of an inch smaller diameter crank journal, first, metal is removed from the mating end of the rod cap, then the cap is fasten to the rod. The big hole in the rod is now oblong or "egg shaped." Then the big hole in the rod is honed until it's .002" larger than the diameter of the crank journal. Honing reshapes the hole into a perfect circle again, only smaller in diameter. This works very well and it lasts as long as an ordinary STD size rod and crank journal. This can only be performed on a rod with a good bearing surface. It cannot be done on a burnt or heavily scored connecting rod because too much metal would need to be removed. Also, if the crank journal is worn beyond .030" undersize, it can be welded up and reground back to STD size. But in most cases, it's cost-prohibitive to have a worn or heavily scored crank journal welded up and reground back to STD size. There's lots of tricks that can be used to rebuild an engine. The rebuilt engine should last a long time, too.

No oil on the dipstick could mean the rod can burn on the crank journal, resulting in an engine knock, and an engine rebuild, or worse case sensorial, a hole in the side of the engine block. Always check and fill the oil (if needed) each time before the tractor/equipment is used just to be certain. Never assume the crankcase is still full of oil the last time you checked it. Because these little "air cooled" engines naturally run hot, especially during warm weather, which can force them to use oil from time to time.

The things that can cause connecting rod breakage are: (Added 5/15/24)

• Extreme engine over-revving for prolonged time with plain bearing surface rod (well above 3,600 RPM with no lead-coated bearing inserts installed).
• Extreme low oil level or lack of crankcase oil.
• Extremely worn crank journal, resulting in engine knocking due to excessive clearance between journal and rod.
• Loose or not properly torqued rod bolts or nuts. (If engine was previously rebuilt.)
• [Factory] flat washers installed on rod bolts instead of split lock washers. (If engine was previously rebuilt.)
• Connecting rod and cap (with oil hole) installed in engine backwards. (If engine was previously rebuilt.)
• Match marks on connecting rod and cap not aligned. (If engine was previously rebuilt.)
• Different cap installed on connecting rod. (If engine was previously rebuilt.)

In most cases, when an engine is ran low on oil or out of oil, a rod with worn bearing inserts will knock. If the rod starts knocking, turn it off immediately and replace the damaged bearing inserts, and then install the proper grade/weight of oil to the full level. But sometimes after prolong running of the engine with worn bearing inserts, the bore in the rod can become oblong or "egg-shaped" after taking a pounding from worn bearing inserts. If this happens, a few thousandths of metal is removed from the rod cap, the cap torqued to the rod, and then the big hole in the rod can be precision-resized to the correct diameter for the bearing inserts with a connecting rod honing machine. If a new bearing is used in a rod with an oblong hole, the bearing may fit too tight on the crank journal, causing it to get hot while in use and possibly burn out from inadequate oil clearance. With bearing inserts, the crank journal may also wear, but most likely not wear. It'll also be wise to check the rod for stress cracks with a strong magnifying glass or better yet, a powerful microscope.

Most of the time, cleaning the burnt aluminum from a crankshaft journal won't work because the journal itself may be scored or worn. Therefore, it'll be better to have it reground to the next undersize and install a matching undersize connecting rod. Or if an undersize rod or replaceable bearing inserts isn't available, have it reground undersize (to wherever it "cleans up") and resize the connecting rod for proper fit.

If a crank journal is worn smooth (not gouged or scored) and if the original plain aluminum bearing surface connecting rod, or even a new plain aluminum bearing surface rod is installed, the rod might knock, but it may last for several years under general lawn and garden use or for stock tractor pulling (4,000 RPM). However, the dangerous vibrating harmonics in the loose rod could cause stress cracks in the rod, eventually leading to rod failure. Bearing inserts cushions the extreme pressure the rod places on the worn journal, which lessens the harmonics, allowing the rod to last longer.

As long as the crankcase is full of oil (splash oil lubrication system) or adequate oil gets to the bearings (pressurized oil pump lubrication system), and as long as the bearing inserts have the proper oil clearance, they should hold up to unlimited engine RPM. If the correct velocity of oil is used, and if the crankcase oil is changed regularly, the bearing inserts should last the life of the engine. You'll also have more confidence knowing your connecting rod(s) has bearing inserts. Return to previous paragraph. È

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High Quality Bearing Inserts for Connecting Rods. Can be used in Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361, KT19 Series II, M20 and MV20. Available in STD size, .010", .020", .030" and borable/resizable .060" (limited supply) undersizes. NOTE: Rod must be bored-out (and notched) to make room for bearing inserts. And a rod with a burnt aluminum surface can be bored-out and bearing inserts can be installed. Click here to learn how bearing inserts protect an engine. Rods for the before mentioned engines can be bored and notched to accept bearing inserts. Even severely burnt, scored, or rods with a mismatched cap can be bored for installation of bearing inserts. Only USA-made Clevite 77, Federal Mogul or Sealed Power bearing inserts will be installed. No low quality Chinese-made bearing inserts ever installed. All A-1 Miller's Professional Machined connecting rods include ground-out notches to prevent bearing rotation in rod and drilled oil hole for proper lubrication. Please indicate diameter of crank journal for size of bearing inserts. (STD size, .010", .020", .030" or resizable .060" undersizes.) Also, rods can be center-bored for top of piston to come flush with deck, or bored .020" offset for a .020"± piston pop-out at no extra charge. [Return To Previous Paragraph, Web Site or Section] Clevite 77 CB278 or CB2279, Federal Mogul 9885CP or 9885CPA, or Sealed Power Bearing Inserts. Please indicate size and tang offset. $25.00 each, plus shipping & handling. Bore and notch your rod only (customer supply and install own bearing inserts): $40.00 labor, plus return shipping & handling. Bore and notch your rod and install our bearing inserts: $65.00 ($25.00 for bearing inserts + $40.00 labor to bore and notch rod), plus return shipping & handling. Purchase one of our high quality rods, bore and notch rod and install our bearing inserts: Price of rod $45 + $25.00 for bearing inserts + $40.00 labor to bore rod = $110.00 total, plus shipping & handling. Click or tap here for A-1 Miller's professional crankshaft rod journal regrinding service. NOTE: If a crank journal is worn beyond specs or badly scored/burnt,it will need to be reground to the next undersize to match the appropriate size bearing inserts. And if you wish to have A-1 Miller's to bore a rod for you, please let me know if you want the bearing insert centered in the bore of the rod (5.300" rod length; piston flush with top of block), offset .020" (5.320" rod length; safe to use with a milled OEM stock head and stock head gasket) or offset .060" (5.360" rod length; use with a non-milled OEM head and stock head gasket) to pop the piston out of the cylinder (see below Ê) to raise the compression and help improve air flow within the combustion chamber for more power and torque. The bearing inserts I install in Kohler 10-16hp flatheads and 18hp OHV K361 connecting rods can be used for general lawn and garden use, stock or high RPM competition pulling engines. The rod will need to be bored exactly 1.625" for proper bearing to journal oil clearance. NOTE: Being virtually all Kohler K241 and M10 pistons come within .020"± from the top of the block, which lowers the compression ratio. (The factory made them this way for reasons unknown.) I prefer to bore the K241 10hp rods .020" offset so the piston will come flush with the top of the block. This will allow the engine to produce a little more power. It won't effect the longevity of the engine or cause any problems whatsoever. But sometimes with the .020" offset, the piston will pop out of the cylinder a few thousandths of an inch, which will still hurt nothing. And the bore can be offset .040" for a .020"± piston pop-out. FYI - Before I machine a rod for installation of bearing inserts, I use a metal "plug" alignment tool that I fabricated to precisely align the big hole of the connecting rod with the centerline of the spindle in my milling machine. Then while the plug is in the rod, I firmly clamp the rod to the milling machine table and after leaving the big hole centered or moving the table so many thousandths of an inch offset for piston pop-out, I lock the table so it won't move in any direction while boring the rod. But for reasons unknown, sometimes the cutting tool will bore the hole in the rod slightly off-center toward one of the bolts or studs. When this happens, I simply grind a small notch on the outside of each bearing shell so they'll clear the rod bolt. I've talked to other machinists who bore Kohler rods also about this and they tell A-1 Miller's sometimes the same thing happens to their rods. But as long as the outside of the bearing shells are notched for clearance of the bolt or stud, the off-center of the bearing inserts poses no problems whatsoever. And bearing inserts for the 10-16hp Kohler engines can be installed in Kohler models K482, K532 and K582 STD size connecting rods, but the crank journals would need to be reground exactly to 1.500" to match the inside diameter of the bearing inserts when installed in the rods. And for your information, STD size crank journals for the K482, K532 and K582 engines measures 1.6245".

Information About the Engine Governor [RPM Limiting/Regulating] System -

First of all, being the governor gear assembly in a Kohler engine model K241, M10, K301, M12, K321, M14, K341, M16 and K361 have 20 teeth, and the crankshaft gear in these engines have 26 teeth, the governor gear spins 1.3 times faster than the crankshaft. (20 ÷ 26 = 1.3) This means when the engine is running at the factory-recommended 3,600 RPM, the governor gear is spinning at 4,680 RPM. And with the engine turning at 4,000 RPM, the governor gear spins at 5,200 RPM. With an open RPM competition pulling engine turning an average of 7,000± RPM, the governor gear (if left inside the engine) turns at 9,100±! Therefore, when building an open RPM competition pulling engine, ALWAYS remove the governor gear assembly and governor components/linkage, and plug the governor stop pin and cross shaft bushing holes with clear RTV silicone adhesive sealant, a 1/2-13 UNC Allen set screw (with Loctite), or a short 1/2-13 UNC bolt to prevent crankcase oil from exiting the engine. And have the rotating assembly (crankshaft and piston/connecting rod) precision dynamically spin-balanced! And for safety reasons, definitely install a steel flywheel and crankcase side shields on the tractor frame for an engine that runs at open RPM.

If you want to do away with the governor, you must remove it entirely from inside the engine block. Otherwise, at high RPM, the flyweights that's attached to the governor gear assembly (which is called the "governor spool") could cause the nylon spool to explode and possibly damage the internal parts of the engine at high RPM. But then you must fabricate a throttle linkage of some kind to activate the throttle on the carburetor. FYI - Piano wire, which is very hard steel solid wire, can be used to replace most OEM throttle/governor links. Usually .080" / 5/64" is the most common size. A torch will be needed to make the "Z" bend at each end. Actually, it can be used for a lot of different things. Just because it's called "piano wire", don't mean it's for pianos only. Piano wire is available at most Ace Hardware stores.

All cast K-series iron block single cylinder Kohler engines come with what is called a throttle stop. It's a small piece of angled steel that's fastened under the lever where the governor spring and solid throttle wire is attached. If an engine doesn't have one, fabricate it out of 1/8" x 1/2" x 2" flat steel. Drill a 1/4" hole 1/2" from one end, and bend it in the middle 90 degrees, and install it under the lever. To limit an engine's RPM of an engine, either adjust the throttle stop so the lever bumps against it, set the governor spring ends in different holes on the [long] governor lever, adjust the throttle wire housing or the linkage.

If the governor spring is removed without noticing where the ends of the spring attached to the levers, there should be slight wear marks on the levers where the spring ends attached. Use a magnifying glass to see the marks. This is what I do to remove all guess work from reinstalling the governor spring in the correct positions.

If a stock governed engine runs with a "hunting" sound (hunt, hunt, hunt, etc.), and the governor lever moves side to side while the engine is running around 3,600 RPM, and if adjusting the carburetor, or resetting or changing the engine RPM (rotating the governor speed adjustment screw or repositioning the end of the governor spring in the holes in the governor lever) doesn't fix the problem, then chances are, the [nylon] governor gear assembly is worn on the stub shaft, and/or the stub shaft itself is worn. This will cause the governor gear to "wobble around" on the shaft, which will cause the governor lever/throttle lever to oscillate, or move or swing back and forth at a regular speed, allowing the engine to run erratically. Usually, failure to keep the crankcase oil changed on a regular basis will cause the [nylon] governor gear and/or stub shaft to wear. To fix this problem, the governor gear and/or stub shaft will need to be machined and/or replaced with new ones. This means the entire engine must be completely disassembled, and then governor gear and stub shaft can be replaced. We realize this is a lot of work just to replace one or two small parts, but this is the only way it can be done. FYI - The nylon governor gear is known to wear more on the stub shaft more than the cast iron governor gear. By the way - the photo to the right -> showing a severely worn governor gear stub shaft, the nylon governor gear it spun on was not worn whatever. This is weird, because usually the moving part wears more than the stationary part. Also, you would think that the soft nylon part would wear more than the hardened steel part. And when replacing the governor stub shaft, to prevent severe wear and possible burning of the nylon gear on the shaft from excessive heat when the engine is first started, ALWAYS lubricate the shaft and the inside of the governor gear with oil if the engine is going to be operated right away, or grease for long-term storage of the engine to prevent the stub shaft from being dry and possibly rusting due to high humidity. Actually, it's a good idea to lubricate everything inside the engine block, not only for lubrication upon engine startup, but because other bare metal parts may rust, too.

For long-term storage of virtually any rebuilt engine or short block to prevent any rust build-up, many knowledgeable and experienced mechanics apply protective rust inhibitor oil spray, white lithium grease spray or automotive chassis grease on the piston rings, cylinder wall(s), rod and main journals, camshaft lobes, camshaft pin, and all other internal engine parts that make contact with each other. This provides a thin film that that seals out moisture, which protects vulnerable internal engine parts so they will not rust due to any condensation that may be present in the air. Because rust is the biggest enemy of internal engine parts. When the engine is first started, the grease will melt, and dissolve and mix with the crankcase oil, which will harm nothing. The reason grease works better than motor oil for long-term storage is because eventually the oil will seep past the ring gaps, and drain off of other internal engine parts, and down into the crankcase, and then all there'll be is a very thin coat of oil, or depending on the length of storage time, any oil at all, to protect the parts upon engine startup, which would likely cause excessive wear to valuable parts. In an engine with an oil pump, grease works better to provide longer lubrication of the rod and main bearings until crankcase oil from the oil pump can reach the journals, which will sling off the oil and lubricate other moving parts inside the engine. And with splash lubrication, crankcase oil is on the journals and other moving parts inside the engine as soon as the engine revs up.

Most of the time, the [nylon] governor gear itself will wear, but not the stub shaft. Because for reasons unknown, for anything that rotates on a shaft, the moving part always wear more than the stationary part. (This happens with a lot of moving parts.) But sometimes the stub shaft will wear also. The best way to tell if the shaft is worn is to slide a new governor gear on it to see if it wobbles. And sometimes it's obvious if the shaft is worn just by looking at it. The entire engine must be completely disassembled to do either of the before mentioned.

How to Remove and Replace the Governor Gear Assembly in a Single Cylinder Kohler Engine -

1. The entire engine must be completely disassembled, including everything inside the engine.
2. Remove the governor gear retaining screw (the Phillips head screw that's on the outside of the block).
3. The governor gear can now slide off the stub shaft.
4. If the engine block is going to be thoroughly cleaned and rebuilt, be sure to remove and save the thrust washer that's on the governor gear stub shaft! This special washer is made of either hardened steel or bronze for durability. It's required to prevent the governor gear assembly from wearing against the engine block when the governor gear is under full pressure from the engine running at higher rpms. Many people are not aware of this small, thin washer because it may appear to be part of the block, and it usually falls out and gets lost while cleaning inside the block. Use a pocket knife or sharp, narrow blade putty knife (gasket scraper) to slide it off the stub shaft to save for reuse. Click or tap here if you need a new governor gear thrust washer. IMPORTANT: Due to high RPM and pressure of the governor gear upon engine start-up, before reinstalling the governor gear, lubricate the stub shaft and thrust washer with motor oil, automotive chassis grease or wheel bearing grease to prevent the governor gear from wearing until the crankcase oil reaches these areas.
5. Install the new or replacement governor gear assembly in reverse order of removal.

How to Replace a Worn Governor Gear Stub Shaft (Pin) in Kohler engine models K141, K160/K161, K181, L160/L161, L181, M8, K241, M10, K301, M12, K321, M14, K341, M16 and K361 - [Return to previous website or section]

1. Remove the governor gear retaining pin, governor gear assembly and thrust washer as described above È. Be sure not to lose the thrust washer!
2. To access the stub shaft, there's no need to drill through and pry out the welch plug from the block! Instead, simply remove the cam gear cover, and through the cover opening, use a long 5/16" steel rod or long screwdriver and medium size hammer to drive out the welch plug from the block. The welch plug presses against and rests on a machined step or shoulder in the counterbore. Therefore, it MUST be removed from inside out.
3. Remove the exhaust valve spring, and going through the welch plug hole opening from the outside the block, use a 5/16" blunt punch and medium size hammer to drive out the stub shaft from the block into the valve spring compartment.
4. To easily install the new stub shaft and so it will be driven or guided straight into the hole, use a high quality 3/8" deep-well impact socket with a high quality short extension and medium size hammer, or fabricate a driver from a 5/8" diameter solid steel rod having a 3/8" diameter x 11/32" or .345" deep drilled hole in one end. Drive the new stub shaft in the hole until 11/32" or .345" protrudes from the block. NOTE: When using a 3/8" socket to install the stub shaft, the depth gauge on a dial or digital vernier caliper will need to be used to measure the installed height of the stub shaft. If the stub shaft is installed too deep, the governor gear assembly will wobble, and if the stub shaft is extended out too far, the center push-pin on the governor gear will make contact with the stub shaft and the flyweights will not function as they should. But if a fabricated driver as described above is machined correctly and used to install the stub shaft, then the caliper will not need to be used.
5. If the welch plug is not damaged, it can be reused. To reinstall it correctly and securely, place it over a 7/8" I.D. heavy wall steel tube or 7/8" socket and use the ball end of a ball peen hammer with a larger hammer to pound the center of the welch plug so it will become slightly concaved (dish-shaped) with the center depressed enough so it will fit in the machined step of the counterbore.
6. Clean out the machined step of the welch plug counterbore with cleaning solvent, and apply clear RTV silicone adhesive sealant in the machined step. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.
7. Place the welch plug in the counterbore with the raised (convex) center facing outward. Use the ball end of the ball peen hammer with a larger hammer to pound the center of the welch plug so it will flatten out and expand to fit tight in the counterbore.
8. Wipe away any excess silicone for a professional-looking job, and the repair is complete! [Return to previous website or section]

How to Adjust/Set the Governor to Set the Top Speed RPM on a Kohler or Virtually Any Small Engine - [Top of Page]

The initial setting for proper operation of the governor for stable engine speed is first loosen the clamp nut on the governor lever and rotate the shaft counterclockwise with the throttle in the full throttle position. Then tighten the nut. After you start the engine, run it a full (governed) speed and select the hole in the governor that allow the engine to run at 3,600 RPM. All centrifugal governor assemblies are made of three parts: Regulating Pin, (2) Flyweights, Governor Gear, and Governor Gear Shaft.

If an engine revs with no closing of the throttle shaft by the governor, or surges, then the governor is either out of adjustment or a governor part is severely worn or broken. To set the governor speed control, first, install the governor parts, install the carburetor on the engine, connect all the throttle linkages, etc. in their respective places, and then...

For the Kohler K-series and Magnum single cylinder K241, K301, K231, K341,K361, M10, M12, M14 and M16 engines, the first thing to check is, there's a tiny blind-end needle bearing (older models) or steel bushing (later models) that's pressed in the block opposite end of the governor cross shaft bronze bushing. Sometimes this tiny bearing or bushing will get pushed outward or fall out of the block when the cross shaft is jammed into something. If it gets dislodged from the block, it will need to be replaced. But if it just got pushed outward, it can be driven back in the block with a hammer until about .010" of end-play clearance is achieved. The clearance/end-play is set by driving either the cross shaft or steel bushing back and forth with a small hammer until proper clearance is achieved. If the cross shaft has excessive crossways clearance/end-play, this will allow the flat lever on the shaft not make contact with the center push-pin on the governor gear assembly, and when the engine is running, the flyweights could bend or break off the lever.

To set the speed control on Kohler single cylinder K-series engine models K141, K160/K161, K181, L160/L161, L181, M8, K241, M10, K301, M12, K321, M14, K341, M16 or K361, with the throttle linkage connected from the throttle lever to the governor lever, block the throttle lever in the wide open position, and loosen the clamping bolt/nut on the governor lever, then rotate the governor cross shaft counterclockwise with ordinary pliers or locking pliers (Vise Grip) as far as it will go, and then securely tighten the clamping bolt/nut.

On rare occurrences, on Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361 and the opposed twin cylinder flathead engines, the hole in the reversed L-shaped governor lever that clamp around the cross shaft will stretch due to metal fatigue from being clamped tightly and sometimes will not grip the shaft as tight as it should. With the lever clamped tight on the shaft, and the correct governor adjustment made, pressure from the flyweights on the governor gear assembly and pressure from the governor spring act as two opposing forces (Newton's third law of motion), which will sometimes cause the shaft to literally slip in the lever. When this happens, the engine will run dangerously at wide open throttle when throttled up with no response from the governor assembly and no regulated governed-control speed at all. There are two ways to prevent this from happening..

• Option 1: Remove the reversed L-shaped lever from the engine, remove the clamping bolt, place the lever in a bench vise, and use a hacksaw to widen the "clamping slot" so the clamp can squeeze the cross shaft much tighter when installed.
• Option 2: With the governor adjustment correctly made, place a small bead of weld on the lever and shaft (in other words, weld them together) so they will be securely bonded together. And if the lever and/or governor needs to be serviced or removed for whatever reason, just grind away the weld.

(Clarified 1/7/24) To set the governor speed control on Kohler opposed twin cylinder KT-series or Magnum engine models MV16, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18, MV18, M20 or MV20, with the throttle lever connected to the governor lever, and with the throttle plate in the wide open position, loosen the clamping bolt/nut on the governor lever and rotate the governor cross shaft clockwise with ordinary pliers or locking pliers (Vise Grip) as far as it will go, then securely tighten the screw/nut on the clamp of the governor lever. IMPORTANT - If the cross shaft is rotated counterclockwise and tightened in place, this will damage the governor assembly as soon as the engine is ran. Complete disassembly of the engine will need to be done in order to replace the governor gear assembly and cross shaft.

Do not mistakenly rotate the governor cross shaft in the wrong direction until it stops, tighten the clamp and then run the engine! Doing this could cause the lever (see below Ê) to jam into the governor flyweights, breaking it off and/or possibly destroying the governor gear assembly.

NOTE: If the above È adjustment was attempted and the governor cross shaft rotates without stopping, this means the flat lever on the shaft has broken off. It can usually be found at the bottom of the oil pan. A broken off lever will allow the engine to operate dangerously at wide open throttle when throttled up. Or, if the governor cross shaft (the shaft that protrudes from the block) gets bent due to rough handling of the engine, and if it's not bent too bad, it can be straightened with a small hammer. (It's made of mild steel.) But if it's bent severely or if it's broken off, it must be replaced. If this happens, usually the bronze bushing will break also and it will need to be machined and/or replaced, too.

To fix either of the above È, either a governor cross shaft that's in good condition can be installed, or the broken-off lever can be successfully TIG-welded or brazed with an oxy-acetylene torch back onto the shaft. To perform the repair of the governor cross shaft, the entire engine must be completely disassembled. This means EVERYTHING inside the engine block (crankcase) will need to be removed. And then the replacement or repaired shaft can (re)installed from inside the crankcase. But before the original shaft is removed, the bronze bushing on the outside must first be removed. The governor gear assembly doesn't need to be removed. The shaft lifts out from inside the crankcase and is installed in reverse order of removal. And it'll be a good idea to place a small bead of weld or braze to secure the flat lever to the shaft to prevent future breakage. (I think this is something that Kohler should have done originally.) I realize that this is a lot of work just to replace a small [important] part, but it must be done in this way. There is no other way to replace it. Before installing, apply oil or grease on shaft for smooth governor action and less wear to shaft and/or bushing.

And that's all that's to it! You can also go here for further details and photos: http://cubfaq.com/govadjust.html. But if doing the above È didn't fix the over-revving or surging problem, then perhaps the governor gear assembly is damaged and/or the stub shaft is worn (wobbling around, which will cause throttle surging), the lever broke off the cross shaft (which will cause the engine to run at wide open throttle at all times), or the throttle plate retaining screws came out of the throttle shaft.

If the governor cross shaft has excessive side to side clearance/end-play, it can be snugged-up by simply tapping the steel bearing opposite end of the brass bushing with a medium size hammer. The bearing is located on the outside and toward the center of the engine block. This will drive the [press-fit] bearing further in the block to lessen the shaft clearance/end-play. FYI - the early bearings had needle bearings, and the later ones is made of solid steel.

And it doesn't matter how long or short the linkage between the governor lever to the throttle lever is because the governor is set by the clamp on the cross shaft. Actually, I don't know why Kohler made the linkage adjustable. It serves no purpose to lengthen or shorten it.

How to Correctly Position the Governor Spring on a Kohler or Magnum Engine - [Return to previous section]

Placing the end of the governor spring in one of the uppermost holes of the reversed L-shaped governor lever on a Kohler engine model K241, K301, K321, K341 and K361, or Magnum engine model M10, M12, M14, M16 decreases the RPM speed of the engine, and placing the spring in one of the lowermost holes of the reversed L-shaped governor lever increases the RPM speed of the engine. The opposite is true with the spring in the holes of the speed control bracket on ordinary Kohler K241-K361 engines (with the short 26 coil governor spring), Kohler AQS "Quiet Line" (K241-K361 models with the 34 coil Extended-Length governor spring) and Kohler Magnum M10-M16 engines (with the 26 coil or 34 coil governor spring). These engines have a top speed of 3,600 RPM (with a fully adjustable high speed jet carburetor) or 3,200 RPM (with a non-adjustable/fixed high speed jet carburetor) with the ends of the governor spring in one of the middle holes of either lever. (Read more below.) Use medium size needle-nose pliers to unhook and reinsert the end(s) of the spring in either lever. Be careful not to distort the ends or overstretch the spring! Or the speed control bracket may need to be unfastened from the block to position or reposition the spring in the holes in either lever.

It's best to set the engine maximum RPM with an accurate tachometer to determine the exact speed of the crankshaft to prevent the engine from dangerously over-revving, which could possibly cause the connecting rod to burn or possibly break, which could destroy the engine block. The maximum RPM for virtually any stock lawn & garden small engine with a fully adjustable high speed main jet carburetor is 3,600; and the maximum RPM for a stock lawn & garden small engine with a fixed/non-adjustable high speed main jet carburetor is 3,200. Moreover, for [Kohler] engines with camshaft-operated ignition points, with certain type of tachometers, the RPM reading/display will need to be doubled. But with crankshaft-operated points or with flywheel-triggered solid state ignition, or with crank trigger ignition, the reading will not need to be doubled.

Advertisement for Tachometers and Tachometer Kits - Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

High Quality Inductive Small Engine Tachometer/Hour Meter with Replaceable Battery. A tachometer is required for monitoring and/or setting the maximum speed of a small engine, which is normally 3,200 or 3,600 RPM (depending on type of carburetor), to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Very accurate, vibration-proof and weatherproof construction. Can be surface-mounted and secured with two screws to monitor engine RPM, or hand-held to set engine RPM. Large 3/8 inch LCD display. Works with magneto or battery-powered ignition systems by selecting engine type by programming S1 and S2 buttons. If tachometer does not turn on automatically as soon as engine starts, press and hold the two buttons at the same time. Instructions included. Reads up to 99,999 RPM. Hour meter reads up to 9999:59 hours/minutes. Programmable maintenance hour setting with service icon, a service reminder when to change oil or other maintenance. Can be manually reset to Zero hours. Easy installation: Single wire wraps around spark plug wire and secured with two supplied nylon zip-ties. No wire terminal connections required. Includes replaceable CR2450 battery. Dimensions: 2" wide x 1-3/4" depth x 3/4" height. $25.00 each, plus shipping & handling. Please let me know if you're interested in purchasing this item and I'll give you the total amount with shipping and payment options. High Quality Digital Tachometer/Proximity Sensor Kits. A tachometer is required in setting the correct engine RPM, which is normally 3,200 or 3,600 RPM (depending on type of carburetor), to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Choice of a RED or BLUE numeric display. Will work with most small engines or multi-cylinder automotive engines, gas or diesel. Very accurate, vibration-proof and weatherproof construction. The great thing about this type of tachometer is that it needs no setup or programming. Displays accurate RPM as soon as the engine cranks over to start. Displays up to 9,999 RPM. Tachometer returns to zero [0000] when engine is shut down. Can be used for lawn & garden equipment or competition pulling engines. Designed to be permanently mounted to monitor engine RPM at all times. Tachometer can be in-dash or panel-mounted. This precision digital tachometer operates with external power and on the same principle as my flywheel- or crank-trigger ignition systems with a proximity sensor to detect the target, which can be a small ferrous steel screw or pin, or magnet in a rotating disc on the crankshaft or on/in flywheel. Operates totally independent of the ignition system, or can be used with crank trigger ignition with the same proximity sensor. Sensor is capable of powering this digital tachometer and crank-trigger ignition module at the same time, with the exception of using the Dynatek Dyna S or PerTronix Ignitor modules. This tachometer must be wired separately or wiring can be incorporated with my crank-trigger ignition system that use a proximity sensor. A sturdy metal bracket will need to be fabricated by customer to mount the sensor in close proximity of the detector/trigger target. Set air gap/clearance at .010"-.188". Tachometer works with 8-24 volts DC, proximity sensor works with 6-36 volts DC. Dimensions for mounting hole for tachometer: 3" wide x 1-17/32" wide. Tachometer measures 1" in depth. Dimensions of proximity sensor: 15/32" diameter threads x 1-3/8" thread length. Wiring Instructions: #1 wire on tachometer connects to BROWN wire on proximity sensor and ignition switch (12 volt power), #2 wire on tachometer connects to BLUE wire on proximity sensor and engine/chassis ground (which connects to the negative (–) battery post), and #5 wire on tachometer connects to BLACK wire on either proximity sensor listed below. Wires #3 and #4 connects to nothing. Wiring is the same for the hall effect and inductive proximity sensors. Certain proximity sensors have an LED (Light Emitting Diode), which flashes when in close proximity of target. If the proximity sensor is wired incorrectly, the LED will illuminate at all times. Click or tap here for YouTube videos to see how well this tachometer works. Tachometer only. Use with virtually any Normally Open 3-wire hall effect, inductive, or cube-shaped inductive proximity sensor (w/flywheel trigger ignition). $22.00 each, plus shipping & handling. Complete Tachometer Kit with Hall Effect Proximity Sensor (dimensions listed below) and Locking Set Screw Collar w/Embedded Magnet. When ordering, please indicate diameter of crankshaft PTO end for locking collar. $47.00 each, plus shipping & handling. Complete Tachometer Kit with Inductive Proximity Sensor (dimensions listed below). Senses the head of a small steel screw installed in a rotating locking set screw collar, disc or flywheel. $32.00 each, plus shipping & handling. Hall Effect Proximity Sensor. Dimensions: 15/32" Diameter x 2-1/2" Length x 43" Cable Length . (Senses the South pole of a small magnet embedded in an aluminum rotating locking set screw collar, disc, or OEM magnet embedded in a flywheel.) $10.00 each, plus shipping & handling. Inductive Proximity Sensor. Dimensions: 15/32" Diameter x 2-1/2" Length x 43" Cable Length Inductive Proximity Sensor. (Senses the head of a small steel screw in stalled in a rotating locking set screw collar, disc or flywheel.) $13.00 each, plus shipping & handling. Aluminum Locking Set Screw Collar w/Embedded Trigger Magnet. Use with hall effect proximity sensors only. $15.00 each, plus shipping & handling. Steel Locking Set Screw Collar w/Steel Trigger Screw Head. Use with inductive proximity sensors or magnetic pickup coils. $15.00 each, plus shipping & handling. When ordering either locking collar listed above, please specify diameter of crankshaft PTO end or shaft it's to be mounted on. Most common Kohler crankshaft PTO end diameters are 1", 1-1/8", but 3/4", 1-1/4", 1-3/8", 1-7/16" and 1-1/2" are rare. Most billet steel crankshafts have a 1-1/2" diameter PTO end (raised shoulder). Other sizes available.

Advertisement for Governor Parts - Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

Kohler Governor Cross Shaft Bushings with Rubber O-Ring to Prevent Oil Leak. Rubber O-ring fits snug in bushing and on cross shaft, and has no effect with movement of governor leverage whatsoever. WHY HAVING THIS O-RING INSTALLED IS IMPORTANT: On single cylinder Kohler engines, vacuum within the crankcase created by the upward stroke of the piston draws in a small amount of outside air, along with a small amount of dust, dirt and debris through the governor bushing and shaft, pressurized air within the crankcase created by the downward stroke of the piston blows out a fine mist of crankcase oil through the bushing and shaft. Overtime, the dust, dirt and debris of this repeated pulsating action will, without a doubt, cause the bushing (and sometimes the shaft, too) to wear, which causes a thin film of oily mess to exist on the outside of the engine block. IMPORTANT INFORMATION UPON REMOVAL OF THE BUSHING: When removing the old bushing, use caution to prevent the governor cross shaft from pulling outward and possibly falling down inside the crankcase! If this happens, the entire engine must be completely disassembled just to reinstall the governor cross shaft in place. Also, before installing this bushing with the O-ring, apply clean oil inside the bushing and O-ring and/or on the shaft for lubrication. With no prior lubrication, the dry bushing and rubber will eventually wear dry from friction, possibly causing a new oil leak. Do the job right the first time, and it won't have to be done again for a long time. Governor Cross Shaft Bushings with 7/32" hole x 1/2-13 UNC threads. Each fits various Kohler engine models K90/K91, K141, K160/K161, L160/L161, L181, K181 and various early M8 engines with V-shaped/coiled governor spring. NOTE: When ordering, please specify engine model, specification and serial numbers, or identification of your bushing. Install new snug-fitting neoprene rubber O-ring oil seal in YOUR governor cross shaft bushing. $10.00 for O-ring and labor, plus return shipping & handling. Repair worn hole in YOUR governor cross shaft bushing with a thin-wall brass sleeve bushing and install new snug-fitting neoprene rubber O-ring oil seal. $15.00 each for all parts and labor, plus shipping & handling. OUR used and in excellent condition governor cross shaft bushing with new snug-fitting rubber O-ring oil seal installed. Discontinued Kohler part #'s 220132 and 230476-S. $20.00 each, plus shipping & handling. (When available.) Governor Cross Shaft Bushing with 7/32" hole x 1/2-13 UNC threads. Fits Kohler engine model K181 w/specification # 301000-301045, and various later M8 engines with coiled extension governor spring. NOTE: When ordering, please specify engine model and specification numbers. Install new snug-fitting neoprene rubber O-ring oil seal in YOUR governor cross shaft bushing. $10.00 each for O-ring and labor, plus return shipping & handling. Repair worn hole in YOUR governor cross shaft bushing with a thin-wall brass sleeve bushing and install new snug-fitting neoprene rubber O-ring oil seal. $15.00 each for all parts and labor, plus shipping & handling. New governor cross shaft bushing with new snug-fitting rubber O-ring oil seal installed. $22.50 each, plus shipping & handling. Governor Cross Shaft Bushing with 1/4" hole x 1/2-13 UNC threads. Fits all Kohler K-series and Magnum engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. Install snug-fitting neoprene rubber O-ring oil seal in YOUR governor cross shaft bushing. $10.00 each for seal and labor, plus return shipping & handling. Repair worn hole in YOUR governor cross shaft bushing with a thin-wall brass sleeve bushing and install rubber lip oil seal or snug-fitting neoprene rubber O-ring. $15.00 each for all parts and labor, plus shipping & handling. OUR used and in excellent condition governor cross shaft bushing with new rubber lip oil seal or snug-fitting neoprene rubber O-ring oil seal installed. Discontinued Kohler part # 235476-S. $20.00 each, plus shipping & handling. (When available.) New governor cross shaft bushing with new snug-fitting rubber O-ring oil seal installed. Machined OEM Kohler part # 41 158 02-S to replace discontinued Kohler part # 235476-S. $22.50 each, plus shipping & handling. 7/32" x 1/4" Diameter Governor Cross Shafts. Fits Kohler engine models K141, K160/K161, K181, L160/L161, L181 and M8. 3-13/16" OEM overall length. IMPORTANT: Due to metal fatigue, the lever on this shaft may break off. When this happens, the engine will run at open RPM. So it'll be a good idea to weld the lever to the shaft. And the entire engine must be completely disassembled to replace this part. Also, before installing, apply oil or grease on shaft for smooth governor action and less wear to shaft and/or bushing. OEM Kohler part # 230540-S. Used, in excellent condition and not welded. $35.00 each, plus shipping & handling. (When available.) Used, in excellent condition and welded. $40.00 each, plus shipping & handling. (When available.) New and not welded. Includes alignment washer (listed below). $76.40 each, plus shipping & handling. New and welded. Includes alignment washer (listed below). $80.00 each, plus shipping & handling. Alignment Washers and Spacer. Fits Governor Cross Shaft listed above. Fits most Kohler engine models K141, K160/K161, KV161, L160/L161, L181, K181 and M8. Goes on governor cross shaft listed above, and locates between governor cross shaft bushing (listed above) and step on cross shaft to maintain proper alignment of lever on shaft with center button on governor gear assembly. Aftermarket Stainless Steel Washer. Dimensions: .223" I.D. x .435" O.D. x .034" thickness. Replaces Kohler part # X-25-58-S. $1.00 each, plus shipping & handling. Steel Washer. OEM Kohler part # X-25-58-S. $2.85 each, plus shipping & handling. Hardened Aluminum Spacer and Aftermarket Stainless Steel Washer. Fits various early K181 engines. Dimensions: .220" I.D. x .343" O.D. x 5/16" length. Replaces discontinued Kohler part # 232739. $6.00 each, plus shipping & handling. 1/4" Diameter Governor Cross Shafts. Fits all Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. 3-13/16" OEM overall length. IMPORTANT: Due to metal fatigue, sometimes the lever on this shaft will break off. When this happens, the engine will run at wide open throttle. So it'll be a good idea to weld the lever to the shaft. And the entire engine must be completely disassembled to replace this part. Also, before installing, apply oil or grease on shaft for smooth governor action and less wear to shaft and/or bushing. Replaces discontinued Kohler part # 237455 (cross shaft with groove and C-clip instead of spacer listed below). OEM Kohler part # A-235256-S. Used, in excellent condition and not welded. $20.00 each, plus shipping & handling. (When available.) Used, in excellent condition and welded. $25.00 each, plus shipping & handling. (When available.) New and not welded. Includes steel spacer (listed below). $41.00 each, plus shipping & handling. New and welded. Includes steel spacer (listed below). $46.00 each, plus shipping & handling. Alignment Spacers. Fits Governor Cross Shaft listed above. Fits all Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. Goes on governor cross shaft listed above, and locates between governor cross shaft bushing (listed above) and lever to maintain proper alignment of lever with center button on governor gear assembly. High quality aftermarket. Dimensions: .260" I.D. x .372" O.D. x 13/16" length. Replaces Kohler part # 25 112 17-S. $1.00 each, plus shipping & handling. OEM Kohler part # 25 112 17-S. $7.15 each, plus shipping & handling. Governor Cross Shaft End Bearing (Tiny Steel Bushing w/Blind Hole). Fits various Kohler engine models K181, L160/L161, L181, M8, K241, M10, K301, M12, K321, M14, K341 and M16 with machined through-hole in block for end of governor cross shaft. OEM Kohler part # 234866-S. Used and in excellent condition. $4.00 each, plus shipping & handling. (When available.) New. $6.60 each, plus shipping & handling. Nylon Governor Gear Assemblies with Symmetrical Flyweights. Fits Kohler engine models K141, K160/K161, K181, L160/L161, L181, M8, K241, M10, K301, M12, K321, M14, K341, M16, K361, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Designed for general lawn and garden work. Also suitable for a 4,000± RPM competition pulling engine. IMPORTANT: Apply oil or grease on stub shaft to prevent wear or damage to governor gear assembly upon engine startup until crankcase oil reach this area. Used, unworn and in excellent condition. $35.00 each, plus shipping & handling. (When available.) New. OEM Kohler part # A-235743-S. $62.65 each, plus shipping & handling. Nylon Governor Gear Assembly with Asymmetrical (Offset) Flyweights. Designed specifically for Kohler engine models K241, M10, K301, M12, K321, M14, K341 and M16 used with an air compressor, generator and/or welding unit. Also ideal for use in a 4,000± RPM competition pulling engine. Recovers engine RPM quickly when under a load and maintains engine RPM at a more steady pace. IMPORTANT: Apply oil or grease on stub shaft to prevent wear or damage to governor gear assembly upon engine startup until crankcase oil reach this area. OEM Kohler part # A-236294-S. $182.20 each, plus shipping & handling. Cast Iron Governor Gear Assembly with Symmetrical Flyweights. Fits Kohler engine models K141, K160/K161, K181, L160/L161, L181, M8, K241, M10, K301, M12, K321, M14, K341, M16, KT17 (first design), KT17 Series II, KT19/KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Recommended for high RPM or wide open throttle competition pulling engines. Will not become distorted or explode at high RPM or at open RPM like the nylon governor gears sometimes do. (Kohler never made a steel governor gear.) IMPORTANT: Apply oil or grease on stub shaft to prevent wear or damage to governor gear assembly upon engine startup until crankcase oil reach this area. Used, unworn and in excellent condition. Discontinued Kohler part # A-237031-S. $75.00 each, plus shipping & handling. (When available. These are hard to find nowadays because not many were made.) Thrust Washers for Governor Gear Assemblies. Fits Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361, KT17, KT17 Series II, KT19, KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. A thrust washer is required to prevent the governor gear from wearing against the engine block when the governor gear is under full pressure from the engine running at higher RPM. Many people are not aware of the thrust washer because it may appear to be part of the engine block, and it usually falls out and gets lost while cleaning inside the block. IMPORTANT: Apply oil or grease on stub shaft to prevent wear or damage to governor gear assembly upon engine startup until crankcase oil reach this area. Hardened Steel Thrust Washers. Recommended for and suitable with a nylon governor gear assembly. Much harder than a grade 8 flat washer. Dimensions: .032" thickness x .380" I.D. x .686" O.D. High quality aftermarket. Hardened Steel Thrust Washer. Replaces Kohler part # 237022-S. $1.00 each, plus shipping & handling. Hardened Steel Thrust Washer. OEM Kohler part # 237022-S. $5.90 each, plus shipping & handling. Bronze Thrust Washers. Recommended for and suitable with a cast iron governor gear assembly. Porous (absorbs oil) and harder than cast iron. Dimensions: .063" thickness x .380" I.D. x .757" O.D. High quality aftermarket. Bronze Thrust Washer. Replaces Kohler part # X-25-67-S. $1.00 each, plus shipping & handling. Bronze Thrust Washer. OEM Kohler part # X-25-67-S. $3.55 each, plus shipping & handling. Governor Gear Stub Shafts. NOTE: Install each stub shaft listed below until .345" (11/32") protrudes from the block, and apply oil or grease on it to prevent wear to governor gear assembly to prevent a dry engine startup until crankcase oil reach this area. FYI - All OEM Kohler stub shafts that originally come in the engine are smooth the entire length. Only new OEM replacement stub shafts are knurled on one end. Therefore, perhaps the OEM stub shaft can be reused by reinstalling it in reverse if the worn half fits tight in the block. Click here to learn how to replace the worn governor gear stub shaft and reinstall the same welch/expansion plug. [Return to previous section] Fits Kohler engine models K141, K160/K161, K181, L160/L161, L181 and M8. Dimensions of each part: .375" diameter x 5/8" length. High quality aftermarket. Made of precision ground, hardened, heat-treated alloy steel. Fits snug (press fit) in engine block. Replaces Kohler part # 230125-S. $10.00 each, plus shipping & handling. OEM Kohler part # 230125-S. $36.40 each, plus shipping & handling. Fits Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361, KT17, KT17 Series II, KT19, KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Dimensions: .375" diameter x 7/8" length. High quality aftermarket. Made of precision ground, stainless steel material. Fits snug (press fit) in engine block. Replaces Kohler part # 235125-S. $10.00 each, plus shipping & handling. OEM Kohler part # 235125-S. $76.50 each, plus shipping & handling. 1-1/8" Steel Welch/Expansion Plugs. Fits Kohler engine models K141, K160/K161, K181, L160/L161, L181, M8, K241, M10, K301, M12, K321, M14, K341, M16 and K361. Replace damaged-beyond-repair or lost welch plug in block to access to governor gear stub shaft. Concave/dish-shaped, not cup-shaped. Flattens out and expands with medium size ball peen hammer when installed with clear RTV silicone adhesive sealant in counterbore. Click here to learn how to replace the worn governor gear stub shaft and reinstall the welch plug. High quality aftermarket. Replaces Kohler part # X-230-11-S. $1.00 each, plus shipping & handling. OEM Kohler part # X-230-11-S. $2.15 each, plus shipping & handling. Governor Stop Pin. Fits Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Replace damaged-beyond-repair or lost welch plug in block to access to governor gear stub shaft. Concave/dish-shaped, not cup-shaped. Expands and flattens out with medium size ball peen hammer when installed with clear RTV silicone adhesive sealant in counterbore. Click here to learn how to replace the worn governor gear stub shaft and reinstall the welch plug. Retains governor gear assembly on stub shaft. Replace worn or damaged governor stop pin. Used and in excellent condition. $3.00 each, plus shipping & handling. (When available.) New. OEM Kohler part # 231355-S. $6.05 each, plus shipping & handling.

Advertisement for Throttle Bracket, Throttle and Choke Cable Assemblies, and High Quality Universal Foot/Gas Pedal Kit - Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

Universal-Fit Replacement Choke or Throttle Control T-Handle. Replace damaged or missing OEM ball-shaped knob or T-handle for more comfortable operation of in-dash or panel-mounted choke or throttle cable control lever. Made of tough, durable plastic. Push-on or use small hammer to install. $1.50 each, plus shipping & handling.

Lever-Action Solid Wire Remote Throttle Control Cable Assemblies. Side mount. Fits Cub Cadet garden tractor models 70, 71, 72, 73, 100, 102, 104, 122, 123, 124, 125, 126, 127 and 147. High quality aftermarket. All heavy duty metal construction. Very close to OEM. Inner wire length: 41-1/4"; Conduit length: 36-1/2"; Wire travel: 1-3/4". A-1 Miller's part # 8626. $29.00 each, plus shipping & handling. OEM Cub Cadet part # IH-384883-R93. $51.00 each, plus shipping & handling. Lever-Action Solid Wire Remote Throttle Control Cable Assemblies. Panel mount. Fits virtually all wide and spread frame Cub Cadet garden tractor models 86, 108, 109, 128, 129, 149, 169, 800, 1000, 1100, 1200, 1250, 1450 and 1650. High quality aftermarket. All heavy duty metal construction. Very close to OEM. Inner wire length: 28-7/8"; Conduit length: 26-7/8"; Wire travel: 1-3/4". A-1 Miller's part # 227. $29.00 each, plus shipping & handling. OEM Cub Cadet part # IH-126465-C2. $41.55 each, plus shipping & handling. Throttle Control Cable Assembly. Panel mount. Fits Cub Cadet garden tractor models 582, 1050, 1204, 1210, 1211, 1282, 1710, 1712, 1806, 1810, 1811, 1812, 1872 and 2072. OEM Cub Cadet part # 746-3002. $44.20 each, plus shipping & handling.

Push/Pull Solid Wire Remote Choke Control Cable Assemblies for all narrow frame Cub Cadet garden tractors. High quality aftermarket. Durable plastic-coated metal conduit to resist rust. Very close to OEM. Inner wire length: 42-1/4"; Conduit length: 40-1/2"; Wire travel: 2". A-1 Miller's part # 72-1196. $20.00 each, plus shipping & handling. OEM Cub Cadet part # IH-384884-R92. $44.00 each, plus shipping & handling. Push/Pull Solid Wire Remote Choke Control Cable Assemblies for all wide and spread frame Cub Cadet garden tractors. High quality aftermarket. Durable plastic-coated metal conduit to resist rust. Very close to OEM. Inner wire length: 35"; Conduit length: 43"; Wire travel: 1-1/2". A-1 Miller's part # 10748. $20.00 each, plus shipping & handling. OEM Cub Cadet part # 946-3011. $35.75 each, plus shipping & handling. Choke Control Cable Assembly. Fits Cub Cadet garden tractor models 482, 682, 782, 784, 1710, 1711, 1712, 1806, 1810, 1811, 1812 and 2072. Not available in aftermarket. OEM Cub Cadet part # 746-3001. $47.55 each, plus shipping & handling. Choke Cable Control Assembly. Fits Cub Cadet garden tractor models 580, 582, 1604 and 1606. Cub Cadet part # 746-3004. Discontinued from Cub Cadet and not available in aftermarket.

Throttle Wire/Cable Swivel Kits. Use to secure stranded cable or solid wire to speed regulating disc or speed control bracket/lever (each listed below) for go-karts, small motorized vehicles, stock/governed Kohler competition pulling engines or secure to throttle lever on Carter/Kohler carburetor for an open RPM Kohler competition pulling engine. Each kit requires a 15/64" / .230" / 6mm hole, and includes wire swivel, screw and friction washer. High quality aftermarket. Replaces Kohler part # 48 755 10-S. $3.00 per kit, plus shipping & handling. OEM Kohler part # 48 755 10-S. $13.53 per kit, plus shipping & handling.

Speed Control Bracket/Lever with 15/64" / 6mm hole for throttle swivel assembly (listed above). Commonly used on most Kohler engine models K241, K301, K321 and K341 with the round shaped metal air cleaner/filter assembly. Not for use on AQS "Quiet Line" engines. New Old Stock or used and in excellent condition. Discontinued Kohler part # 235086-S. $4.75 each, plus shipping & handling. Speed Control Bracket/Lever with yoke, for use with a grooved end adjustment screw (discontinued Kohler part # 237574-S) on various Kohler 10-16hp engines. Sets engine RPM at desired/fixed position. Commonly used on generators/welders, water pumps, etc. OEM Kohler part # 236413-S. $10.70 each, plus shipping & handling. NOTE - We have the capability to fabricate and duplicate obsolete and hard to find throttle linkages and levers. If interested, please email me a photo of the part(s) that's needed (if possible) with the exact dimensions.

Use a Foolproof Type of Foot-Operated, Spring-Loaded, Throttle Return Control Setup on a Competition Garden Pulling Tractor - [Top of Page]

For a distinctive and noticeable appearance, install a chrome-plated, die-cast aluminum barefoot gas pedal on a competition garden pulling tractor. This nostalgic item was popular in the late '60s to early '70s and was used mainly on street rods and hot rod vehicles of the time. This barefoot pedal can be easily clamped or fastened to the universal pedal listed above, or a medium size household brass (to prevent rust) door hinge can be used to fasten this pedal to the foot rest/support/running board of the tractor.

When using a Carter or Kohler carburetor, a spring-loaded throttle control is a safety feature because the engine will idle down as soon as the driver lets off the gas pedal, just like in an automobile. But with the OEM-type, manually-operated solid wire throttle control, the driver must quickly reach for the throttle lever to idle down the engine. Many pulling association/club sanctioning general rules and requirements state that a spring-loaded throttle control must be used for safety, either hand- or foot-operated (hand lever or foot pedal). All Mikuni carburetors have a built-in spring-loaded throttle return.

Stranded Wire Cable Spring-Return Throttle Control Setup for 10-16hp 4,000 RPM Governed Kohler Competition Pulling Engines -

To fabricate a stranded wire cable spring-return throttle control setup for a 4,000 RPM governed 10-16hp Kohler competition pulling engine or small all terrain vehicle engine, replace the upper left cam gear cover bolt with an extended 1-1/2" length bolt and jam nut. Attach a stiff extension spring to the extended bolt and in the second hole down in the speed control bracket. The governor spring will need to be positioned in the top hole in the speed control bracket. Use a stranded wire throttle cable and attach one end to the wire swivel in the speed control bracket. If fabricated correctly, and properly installed and adjusted, this type of throttle control should last a long time with very little wear to the stranded wire cable.

All stranded wire cable housing assemblies come shipped dry from the factory. Therefore, when using a stranded wire cable control to operate the throttle, in order for the inner cable to slide back and forth inside the housing with ease and less friction, remove or pull out the inner cable from the housing (with one [ball] end cut off), and pump motor oil, or better yet, use a chainsaw bar tip grease gun to pump a small amount of lubricant inside the housing so the cable will slide smoother and easier with less friction. But before reinserting the cable in the housing, and to prevent the end of the cable from unraveling, which will make it very difficult to reinsert the cable into the housing, singe the end of the stranded wire with a propane or oxy-acetylene torch (with a small, blue flame) to melt the strand of wires together and then grind down the lump of molten metal to a point so the cable can be easily inserted in the housing and through the wire swivel clamp with no difficulty.

Oh, and if you've ever wondered what a "dead man's throttle" is, it's a spring-loaded foot pedal or hand throttle lever control that automatically returns the throttle plate to the idle position when the pressure is released. It works the same as the gas pedal in a car.

How to Limit the RPM and Safely Operate Virtually Any 4-Stroke Small Engine Without a Working Governor [Top of Page]

Certain Kohler engines came from the factory without a governor assembly and with no provisions in or on the block to install governor components. These particular engines were made for a specific use or for a lightweight vehicle, such as for a go-kart, King Midget micro car, older snowmobile, etc. Being there's no governor components in these engines (listed below) that automatically opens the throttle when the engine is under a load, these are capable of running at wide open throttle, and can't be used for general lawn and garden usage, so caution must be taken not to over-rev the engine for a prolong time to prevent connecting rod burning or breakage, or possible flywheel explosion.

Kohler engine models K141, K161, K181, K241 and K301 that originally came with no factory-installed governor components have the following specification numbers: K141-29169, 29172, 29186, 29189, 29190, 29191, 29238, 29252, 29275, 29333; K161-2889, 28143, 28425, 28560, 28575, 28663, 28729, 28763, 28797, 28838, 28934, 28947; K161-2889, 28143, 28425, 28560, 28575, 28663, 28729, 28763, 28797, 28838, 28934, 28947; K181-30102, 30123, 30124, 30129, 30130, 30138, 30142, 30151, 30165, 30166, 30167, 30169, 30181, 30185, 30216, 30224, 30225, 30228, 30235, 30240, 30242, 30259, 30262, 30268, 30269, 30288, 30306, 30307, 30308, 30310, 30317, 30325, 30384; K241-46202, 46254, 46393 and 46447; K301-4743, 4751, 47103, 47119, 47127. All other Kohler engine models/specs not listed have governor components installed by the factory.

Here's how to limit the RPM for a virtually any engine without a governor: the camshaft is simply advanced by one tooth in relationship to the crankshaft. (The engines mentioned above DO NOT have the cam advanced.) With the cam advanced by one tooth, at full throttle and when the engine is under a load, it will NOT rev at wide open throttle and throw the rod. The engine will still produce plenty of power to get the job done. Advancing the cam opens the valves sooner than normal. In return, this allows the engine to run at a much lower compression. At full throttle, a low compression engine will NOT rev as high as a high compression engine. (The Ford Model T engine, that have a 4:1 compression ratio, will only rev to around 1,750 RPM at full throttle.) The lower compression does not shorten the life of the engine. In fact, it helps to extend engine life because under low compression, the combustion chamber heat operates at a lower temperature, allowing the engine to naturally run cooler, which helps it last longer. NOTE: The camshaft in the Kohler K-series engines cannot be advanced at all because the ignition points operate off the cam, which sets the correct ignition timing. The cam can be advanced with a Kohler Magnum (with solid state ignition) or if the Kohler K-series engine have crank-trigger or flywheel-trigger electronic ignition.

With the cam advanced by one tooth, if the engine is in good condition, it should start quickly, idle smoothly and produce plenty of power up to around 3,400± RPM at full throttle when under a load. But when using camshaft-operated ignition points and with the cam advanced one tooth, this would also advance the ignition timing way too far. Regarding the Kohler K-series engines, being the ignition points operate off the cam and being the camshaft is advanced by one tooth, the ignition timing will be far too advanced for the engine to start easily and run correctly. Therefore, for the timing to be set at 20º BTDC, the engine will need to have either Breakerless Ignition, magneto to solid state ignition conversion, Kohler Magnum solid state ignition, or a custom flywheel-trigger electronic ignition system, which are all triggered by the flywheel, or custom crank-trigger electronic ignition system, which is triggered off the crankshaft.

As a matter of fact, the camshaft was advanced by one tooth on Tecumseh Engines with certain older (mid 1970's era) Sears Craftsman Eager 1 walk-behind or self-propelled lawn mower engines that have no governor components installed by Tecumseh. The remote solid wire cable connect directly to the carburetor throttle lever to vary the engine speed (up to around 3,400± RPM at full throttle). Certain models (4hp/LAV40?) of mid-1970's Sears Craftsman Eager 1 walk-behind or self-propelled lawn mower engines with no governor components have either a very low compression cylinder head with an extremely huge combustion chamber to lower the compression ratio significantly, which limit the engine speed up to around 3,400± RPM; and other models of mid-1970's Sears Craftsman Eager 1 engines with no governor components have a cylinder head with an ordinary size combustion chamber and a carburetor that have an extremely small diameter throttle bore and an extremely small inside diameter intake extension tube that reduce the velocity of air/fuel the engine can draw in, which lowers the compression and limit the engine speed up to around 3,400± RPM). (Incidentally, this works exactly the same as the restrictor plate used in certain sanctioned racing go-kart and NASCAR classes.) And certain other models of mid-1970's Sears Craftsman Eager 1 engines with no governor components have a cylinder head with an ordinary size combustion chamber with a carburetor/intake extension tube of ordinary size, but the camshaft is advanced by one tooth in relationship to the crankshaft, which lowers the compression and limit the RPM up to around 3,400±. These are all proven designs to limit the engine RPM and works very well. These engines still produced plenty of power to get the job done. (We know this for a fact, because after the tune-up or repairs and blade sharpening, we tested each one in tall field grass and they did not lug down whatsoever.) Personally, back in the day (early 1980's), we've had all of these Sears Craftsman Eager 1 engines in our shop brought to us by customers for a tune-up and/or repairs. These are apparently very rare engines. If they were not in our shop at the time, we would not have known that they existed. And we don't know why new small engines like these are not available today. Every small engine manufactured nowadays have a working mechanical governor.

Another way to limit the RPM of an engine without a working governor and the camshaft aligned with the crankshaft is to install multiple cylinder head gaskets or a thick metal plate sandwiched between two head gaskets to lower the compression pressure in the combustion chamber dramatically. This too, will prevent the engine from accelerating to its full potential at wide open throttle. The number of head gaskets or thickness of the plate determines to maximum RPM of the engine.

And yet another way to limit the RPM of an engine without a working governor, with the camshaft aligned with the crankshaft, and with a normal compression ratio is to install a restrictor plate with a specific hole size between the carburetor and intake tube or engine block.

The three methods above can be useful with an engine in go-karts, King Midget micro cars, older snowmobiles, older small all terrain vehicles, etc. And being there's no governor whatsoever, it cannot be altered or readjusted to allow the engine to accelerate at dangerously higher RPM. The engine speed will be limited by the low compression ratio or restricted airflow intake only.

Pulling at Open RPM With No Operating Governor - (added 5/23/15

On a pulling engine that pulls at open RPM, and the governor will never be used, remove all the governor parts inside the crankcase and outside the engine, and plug the hole in the block where the brass governor bushing goes with a 1/2" UNC (coarse thread) Allen set screw. Clean the threads and use liquid threadlocker (Red Loctite or Permatex) to secure the screw in place. FYI - When storing an opened container of liquid threadlock material or Super Glue, store it upright and not laying flat. The [capped] tip will not dry out and clog when stored upright. By getting rid of all the governor parts, this makes for a "clean-looking" and professionally-built pulling engine.

Upon installation of a connecting rod in a Kohler engine, make sure the match marks on the rod and cap are aligned so the hole will make a perfect circle around the crank journal. If they're not aligned, the circle will be offset, resulting in crankshaft binding and possible rod/cap distortion when the bolts or nuts are torqued to specs. Also, make sure the oil hole in the rod cap faces the camshaft so the hole will pick up the oil and lubricate the rod better.

Connecting rods, rather being OEM or aftermarket (stock or high performance), and despite how well-balanced the rotating parts are in a pulling engine, suffer a lot of stress at open RPM in a single cylinder engine. Therefore, if possible, before purchasing a used rod, it's best to look it over for hairline cracks with a strong magnifying glass or better yet, a microscope. And as I always say about buying anything off of eBay: BUYER BEWARE! So ask for a money-back guarantee, or you may have nothing but a piece of scrap metal on your hands.

If using a stock connecting rod above 4,000 RPM, an aluminum bearing surface rod should never be used. Because the extreme pressure and heat from the rapid rotation of the rod on the crankshaft journal causes the aluminum to swell and this could cause the oil clearance to lessen making the aluminum have contact with the crankshaft, minimizing the oil clearance, which will overheat and become scored, resulting in crankshaft journal/rod scoring or burning, engine seizure or even rod breakage. One way around this, if replaceable bearing inserts isn't available for your particular rod, is to have the rod surface enlarged an additional one thousands of an inch (.001") to allow for additional oil clearance (the extra .001" of clearance will not cause the rod to knock) and to make room for the aluminum to swell when it gets hot. Or if your rod can accept bearing inserts (10hp-16hp Kohler rods), have automotive-type bearing inserts installed, even if the rod is new or used, or if it has a relatively good bearing surface. The reason bearing inserts work best in high performance or heavy duty conditions is because the soft babbitt material (lead) that's on the inserts can withstand extreme heat and extreme pressure. It also "cushions" the extreme pressure that the rod places on the crankshaft journal at open RPM. And it's still a good idea to have an additional .001" of additional oil clearance, even if bearing inserts are used. Using bearing inserts also strengthens a [stock] rod by cushioning the severe impact the rod places on the crankshaft at very high RPM.

If a plain aluminum bearing surface connecting rod is scored or burnt on the crankshaft, the causes are either...

Too low oil level or engine out of oil. Oil dipstick calibrated wrong. (Kohler made 23 different lengths and types of dipsticks.) Go here for important information regarding oil dipsticks. Oil dipper broken off of rod cap. Malfunctioning, worn oil pump or clogged oil filter (with no by-pass valve). Too high engine RPM.

Insufficient oil clearance between rod and crank journal in accordance with manufacturer's specs or for a high-revving engine. Use of petroleum motor oil instead of full synthetic oil in a high-revving engine. Rod installed backwards or cap installed backwards on rod. Mismatched rod and cap.

No connecting rod in any 10hp-16hp K-series Kohler engine come from the factory with bearing inserts in them. The rod must be machined (bored and notched) for installation of bearing inserts. Kohler don't make bearing inserts for the connecting rod in any of their single cylinder engines. But the bearings fit the Kohler rod perfectly after it's been bored out. The bearings are available in STD, .010", .020" and .030" undersizes. Also, these bearings can only be used in Kohler engines with a 1.500" diameter crankshaft journal/crank pin (or undersizes), such as the 10hp through 18hp single cylinder engines and all of their opposed twin cylinder engines with a stock (OEM) or an aftermarket connecting rod. No bearing inserts that I know of is designed for use in any other Kohler engines, except for the Kohler engine models K482, K582 and K682 if the crank journals were reground to 1.500". (STD size is 1.625".) The connecting rods would not need to be bored, being they are already 1.625" in diameter. But they would need to be notched for the tangs on the bearing inserts.

Or, being the K241 and K482 engines share the same pistons and have the same stroke, and their connecting rods are the same length, a K241 connecting rod can be used in a K482 engine when bored and honed to 1.625"-1.626" to match the STD size K532 or K582 crank journal, which are 1.624" (allow .001"-.002" for oil clearance). If the K482 journals are worn and reground undersize, the K241 rod can be bored and honed to fit the undersize journals. The oil dipper on these rods will need to be cut off as well. Boring these single cylinder engine rods will not weaken them whatsoever because they hold up very well when bored and used with bearing inserts in the respective single cylinder engines.

To install bearing inserts in virtually any connecting rod, accurately measure the STD size diameter of the crank journal, add the thickness of each bearing insert shell, and this will give the exact diameter of the hole in the rod that needs to be bored. But not all connecting rods will accept bearing inserts, and bearing inserts are not available for certain rods.

About Machining a Connecting Rod for Installation of Replaceable Bearing Inserts - Before I machine a rod for bearing inserts, I use a metal "plug" alignment tool that I made in my metal lathe to precisely align the big hole of the connecting rod with the centerline of the spindle in my milling machine. Then while the plug is in the rod, I firmly clamp the rod to the table of my milling machine and after leaving the big hole centered or moving the table offset for piston pop-out, I securely lock the table so the rod won't move in any direction. But for reasons unknown, sometimes the cutter/reamer will bore the hole in the rod slightly off-center and make contact with one of the bolts or sleeves (for studs) in the rod. Whenever this happens, I simply grind away (notch out) part of each bearing shell so they'll clear the rod bolt or sleeve. I've talked to other experienced machinist who bore Kohler rods about this and they told A-1 Miller's sometimes the same thing happens with them. But as long as the bearing shells are ground for clearance of the bolt/sleeve, this poses no problems.

For high RPM use, bearing inserts also need additional oil clearance. Therefore, it's good insurance to have the crank journal ground an additional .001" for extra oil clearance. As the rod and journal swell due to the rapid rotation of the two parts, metal to metal contact won't happen. Of course, it's a good idea to use full synthetic oil, too. And once a journal's been reground to exactly .010", it's awful hard to ground an additional .001" on it, making it .011" undersize. If the journal has been ground to exactly .010", the rod would need to be honed an extra .001" instead.

Sometimes an OEM connecting rod will need to be bored for installation of bearing inserts when the crank journal must be reground deeper than .010" undersize. (STD size and .010" undersize OEM connecting rods are the only two sizes that's available from Kohler.) But bearings are available in STD, .010", .020" and .030" undersizes, to match the reground journal. If your crank journal needs to be reground to .020" or .030" undersize, then undersized bearing inserts will need to be installed in the rod to match the diameter of the crank journal. Bearings can only be installed in the 10-16hp single cylinder flathead Kohler engines, the 18hp OHV single cylinder Kohler engine, the KT21 and M20 opposed twin cylinder Kohler engine, because these engines all have a 1-1/2 diameter crank journal. Bearing inserts also help to provide longevity of the journal, just like in automotive engines.

More Information About Replaceable Bearing Inserts (Rod Bearings) -

For pulling applications, the oil clearance between the rod bearing and crank journal should be .0015"-.0025" with ± .0005" for wear. The .0025" allows .001" more clearance for rod swelling (when hot; only at open RPM). It'll be good to use this clearance for stock engines, too.

Bearing inserts provide a little more oil clearance to protect the crank journal. If checking the oil clearance with PlastiGage, and if it shows the clearance to be .0015"-.0025", don't worry about it. It'll work just fine. Many race cars run this much clearance. The rod won't knock either.

Boring a Kohler rod and installing bearing inserts in it doesn't weaken the rod whatsoever. Because whenever a rod breaks, 99% of the time they break in the beam section, not around the bearing area. And bearing inserts add very little weight. Meaning they don't upset the balance of the piston/rod assembly to the crankshaft's counterweights a great deal, even at very high RPM.

With engines when there's no an undersize connecting rod or bearing inserts available, if the crank journal is worn beyond STD size and need to be reground, being 99% of all worn journals are "egg-shaped" or oblong, it can be reground to where it is perfectly round again, and then the connecting rod can be resized so it'll fit the smaller diameter undersize journal. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break.

To resize the rod so it'll fit to a few thousands of an inch smaller diameter crank journal, first, metal is removed from the mating end of the rod cap, then the cap is fasten to the rod. The big hole in the rod is now oblong or "egg shaped." Then the big hole in the rod is honed until it's .002" larger than the diameter of the crank journal. Honing reshapes the hole into a perfect circle again, only smaller in diameter. This works very well and it lasts as long as an ordinary STD size rod and crank journal. This can only be performed on a rod with a good bearing surface. It cannot be done on a burnt or heavily scored connecting rod because too much metal would need to be removed. Click or tap here if you're interested in having this service performed.

Be Professional and Not a Slob When Rebuilding an Engine!

The cast iron block Kohler engines are like the old school Chevy V8 engines , they're worth rebuilding. Anyway, always be well-organized and professional whenever rebuilding any engine! Before assembling a fresh engine, always take the time to provide a neat and absolutely clean work environment. Make sure the tools that's used, engine parts, shop towels and your hands are absolutely clean. Things don't necessarily need to be perfectly clean when disassembling an engine, just clean when reassembling an engine. The work environment, tools and equipment represents professionalism, and the quality of workmanship. The repair table or bench should be large enough for the engine block, engine parts and tools that's needed for the rebuild, and sturdy enough to support the weight of a fully assembled cast iron bock Kohler engine, and it's best that it has a steel top with [short] angle iron (steel) edging to keep things (parts. tools, etc.) from falling off the table, and possibly getting dirty on the floor or worse yet, lost. Don't allow any dust and dirt to enter the work area, including the engine block and it's internal parts. If necessary, place the engine parts on a large, clean cloth or cardboard to keep them clean and organized until they're ready to be installed. The reason everything should be kept as clean as possible is because even the smallest amount of dirt inside an engine will "grind away" at the internal parts when the engine is in operation, causing unnecessary and expensive wear. This is especially important for an engine with splash lubrication, and without an oil pump with an oil filter adapter and oil filter.

Use a large cookie sheet placed on a bench or work table to disassemble a small engine, transaxle or anything that contains oil to keep an oily mess off the work area. And then an automotive engine stand can be used to rebuild a Kohler engine. Just use the two bolt holes for the starter motor on the side of the block to mount your engine to the stand. You can completely disassemble and reassemble the entire engine, except for the starter, and you can get at everything on the outside and inside of the engine with no problems.

To "basically" overhaul or rebuild an engine that burns a lot of oil, all that needs to be done on a Kohler engine is remove the oil pan and cylinder head, disconnect the connecting rod from the crankshaft and then drive the piston and rod out of the block with a long wooden stick and a medium size hammer. Inspect the entire piston and cylinder wall for wear. If no wear is evident, then install a new set of rings on the piston (thoroughly clean the parts first though) and reinstall the piston in the block as described. But to do a professional and complete rebuild, read the rest of the information in this web page and linked pages.

Building a competitive and durable pulling engine require a great deal of expertise and skill. All the parts must be machined to precise specifications, and then assembled and installed in the engine, be within precise dimensions so they won't wear excessively, score or burn. But first, read your association/club sanctioning rules and requirements regarding the engine, so when built, it will be legal within its class. If you feel that you can build your own engine and have full confidence that it will perform flawlessly, then that would be fine. Otherwise, you can have A-1 Miller's build your engine.

It's common knowledge that most metals retracts (shrinks) a few thousandths of an inch when cool or cold, and expends (swells) a few thousandths of an inch when warm or hot. Knowing this, when building or rebuilding an engine, keep in mind that if the engine parts are either cool or warm, the clearance/end-plays for the camshaft, crankshaft, valves, piston-to-cylinder wall, etc., will vary according to the temperature conditions the engine is being assembled under. According to the manufacturer's clearance specifications, allow for slightly greater clearances if the temperature is cool (when working in a shop that don't hold heat well during wintertime), and for lesser clearances if the weather is around 72° F. Actually, it's best to build or rebuild an engine during warm weather with the engine parts warmed at room temperature around 72° F.

How to Thoroughly Clean Dirty Engine and Virtually Any Other Dirty, Oily Parts - [Return to previous website or section]

NEVER USE GASOLINE, BRAKE CLEANER OR ANY OTHER HIGHLY FLAMMABLE LIQUID TO CLEAN YOUR HANDS OR PARTS! Gas and brake cleaner cleans great, but is extremely flammable, making it very dangerous and unsafe to use out in the open. And although diesel and kerosene fuels works great for cleaning engine parts, these leave an oily residue or coating on parts that will not dry out, and these are highly flammable as well. Therefore, the best and safest products to clean engine, transmission and other parts for rebuilding is with [clear] paint thinner or odorless mineral spirits. These are petroleum-based solvents that effectively removes grease and oil. They evaporate quickly and is often used in automotive cleaning. And although these can burn too, they have about the same flash point as ordinary charcoal starter fluid. So don't use these near open flames and don't smoke while using either one. Also,paint thinner and mineral spirits are a "dry" liquid and non-oily. These dry with no oily residue and no signs of ever being on the part. They actually mix equally with and dry out the oil or grease that's already on the part. FYI - Most [high dollar] commercial engine parts cleaning solvents is just ordinary paint thinner or mineral spirits with a colored dye, making it their trade-marked product. For safety and convenience, use [clear] paint thinner or odorless mineral spirits in a professional parts washer machine to clean parts.

By the way, when using cleaning solvent to clean dirty oil/debris from your hands, be sure to thoroughly wash off the solvent with soap and water afterwards to prevent drying of your skin, which could cause the backside of your hands to feel itchy. Then use moisturizing hand cream to replenish the natural moisture in your skin.

Paint thinner or mineral spirits will mix equally with oil-based products because they're both a petroleum product. Paint thinner and mineral spirits can also be used to dry out parts covered with motor oil, automatic transmission fluid, hydraulic oil, gear oil, power steering fluid, etc. It works great to clean up an oily mess that's spilled or leaked on a concrete floor, too. Just pour some thinner on the oily mess, use an (old) whisk broom to thoroughly mix the thinner with the oil, let dry, and eventually the oil will dry out along with the thinner with very little to no signs of the oil ever being on the floor. Also, if [clean] motor oil has contaminated and clogged a new or good pleated air filter, there may be no need to discard the filter and purchase a new one. The filter may be put back into service by soaking it for a few minutes in paint thinner or mineral spirits (again, these will mix equally with oil), and then use 150± PSI compressed air with an air blow gun nozzle to clear out any remaining residual or debris from the filter. And again, as the paint thinner/mineral spirits dries, the oil will dry out, too.

Another product that works great for cleaning engine parts is Greased Lightning^® Multi Purpose Cleaner. But use caution when using this product! It will remove paint also. So it's best to use it on bare metal or parts that need repainting.

Cast iron engine blocks shouldn't be internally cleaned with sandblasting because some of the sand can become lodged in the pores of the cast iron and loosen when the engine is in operation, causing severe internal engine wear and damage. Media-blasting with crushed walnut shells works better because it will not become lodged into the cast iron. (Available at Harbor Freight Tools.) The best way I found to clean an engine with stubborn or caked-on external grime, debris and dirt is to use household oven cleaner, such as EASY-OFF^® or equivalent. Use the fume-free brand so you can breath. If using the heavy duty brand, use in a well-ventilated area and be sure to wear a dust mask or surgical face mask. (If you don't, you may wish you did.) Just spray the steel and cast iron parts thoroughly, let set for 15-30 minutes, then blast the grime and debris off with a minimum 1,000 PSI water pressure washer. The low pressure of a household garden hose will not work as well. And if oven cleaner will not remove the stubborn grime, take the cast iron and steel parts to an automotive machine shop and have them "hot tanked", and have the aluminum parts lightly sandblasted. Try to avoid getting oven cleaner on shiny aluminum! The corrosive acid in oven cleaners will discolor aluminum and cause it to have a "chalky" look when the oven cleaner dries. Personally, I coat the parts with fume-free oven cleaner from Dollar General and then use my 1,000 PSI water pressure washer outside of my shop to clean blocks and related parts. Works great every time! After cleaning, blow-dry the parts and be sure to coat the bare metal with WD-40 or equivalent so it won't rust. Rust will form within minutes after the water has dried. And there's no need to remove the WD-40 or equivalent from inside the engine crankcase because it will mix safely with the motor oil when the rebuilt engine is ran. But if a bare engine block (or any cast iron/steel engine part) is stored for a long period of time, it'll be a good idea to cover it, because in time, the WD-40 will attract dust and dirt.

Or if you've ever noticed when dirty, greasy and oily automotive parts are left outside and exposed to the weather for several years, how rain water from the sky will wash off the dirt, grease and oil down to the bare metal? Well, try soaking dirty, greasy or oily engine parts in a tub or container of plain, cold water. Add windshield washer fluid or a water-based engine degreaser, such as Simple Green Degreaser, Greased Lightning Degreaser, or an equivalent product to help with the cleaning process. Do not agitate or heat (boil) the water to try to clean the parts better, for this will oxygenate or introduce oxygen in the water, which could cause the bare metal steel or cast iron parts to rust. After soaking for 3-4 days, take the parts out of the tub or container and use a minimum 1,000 PSI water pressure washer to thoroughly clean the parts. I've done this for many years and it works great! And most importantly, after the parts are cleaned, thoroughly blow the water off the parts using 150± PSI compressed air with an air blow gun nozzle and coat the bare metal steel or cast iron with WD-40 immediately to disperse any remaining water that may have seeped into the cast iron parts to prevent rusting due to exposure to the atmosphere. Do not allow the parts to air-dry! Air-drying will allow rust to develop on bare metal steel or cast iron in a matter of minutes.

How to Remove Surface Rust from Steel Items, Cast Iron Engine Blocks and Cast Iron Cylinder Heads -

White Vinegar Can Remove Rust! How it works: Vinegar's acetic acid reacts with rust, a metal oxide, to create salt and water, which helps dissolve rust (iron oxide) effectively. This process is called neutralization. This makes it a good choice for cleaning ferrous metal surfaces. Non-Toxic: Unlike some commercial rust removers, vinegar is non-toxic and environmentally friendly, making it safer to use. How to use vinegar to remove rust -

• Spray it on: Pour the undiluted white vinegar in a spray bottle, apply it to the rusted part to be cleaned, allow it soak for at least 30 minutes.
• Scrub: Use a soft-bristle brush, steel wool, or scouring pad to scrub the rust off. For small areas, use an old toothbrush or stiff bristle brush.
• Submerge: Put the rusty item in a bowl of undiluted white vinegar and let it soak for at least 30 minutes. For heavy corrosion, soak overnight or up to 24 hours.
• Use a water pressure washer to blast the vinegar and rust from the part. Allow the part to air dry, then apply WD-40 to prevent it from rusting again.
• Repeat: If any rust remains, repeat the process or try another cleaner (listed below).

EVAPO-RUST^® and Metal Rescue™ are very safe products to use and works wonders to remove rust and loosen virtually any rusted or corroded metal part! Just soak the rusted or rusty part for 1 hour for light rust and up to 12 hours for extremely heavy rust. These products are very safe to use and they work wonders on virtually anything that's rusted!

Use a heavy duty bathroom toilet bowl cleaner. Most of these will remove rust and scale. If it reads on the label that it will remove rust, then that's the one to use. This is what I use on some of the blocks I get in that need cleaning. We just apply the cleaner on the block, allow it to soak for about 30 minutes and then use a minimum 1,000 PSI pressure washer to thoroughly clean the part. The rust and grime will come right off!

GUNK Liquid Wrench® also works wonders to loosen virtually any rusted or corroded metal part! Just spray the ends of the throttle or choke shaft, let soak for about 30 minutes or perhaps overnight, then use small Vise Grips to GENTLY rotate the shaft back and forth . Don't force it because it could become twisted and/or break off at the closest plate retaining screw hole! It may rotate (loosen) just a few thousandths of an inch. After it rotates slightly, spray it again and gently rotate it again. Eventually, it should rotate more and swivel 100% free.

Painting Aluminum or Cast Iron Engine Blocks and Cylinder Heads -

To get paint to stick to aluminum, the shiny and slick surface of aluminum will need to be "roughened up" with sandpaper or sandblasting so the paint (or primer paint) can grip or adhere into the microscopic scratches and crevices from the sanding or sandblasting.

To get paint to stick to a cast iron engine block (and/or cylinder head) is with the cast iron being absolutely dry. Cast iron is porous, like a sponge. It soaks up oil, and when something is painted that has oil in it, the paint may eventually peel off because the paint itself cannot soak into the cast iron so it can grip or adhere to it. To get paint (or primer paint) to stick to a used or "seasoned" cast iron block, the cast iron will need to be thoroughly heated to burn out the oil. Soaking the block in a hot tank with a chemical solution at an automotive engine machine shop will clean a lot of the oil out of the cast iron. But placing the block in a special oven furnace and rotating it against large flames will definitely burn out the oil. Then painting the inside of the block with quality paint or primer before reassembly should prevent the crankcase oil from seeping through the cast iron and making a mess on the outside. This is why Cub Cadet garden tractor transaxles are painted on the inside. Kohler never painted any of their [cast iron] blocks on the inside. And if you're looking for some yellow paint to paint your Cub Cadet garden tractor with, try your local farm and home supply store. They usually have International Harvester Yellow. It closely matches the color of Cub Cadet yellow.

Information About Using Imported/Aftermarket Engine Parts -

Most imported pistons, rings, rods and other parts from Rotary or Stens hold up VERY WELL. We've used these parts in our own equipment and pulling tractors for many years and we've sold them to our customers with no complaints whatsoever. Besides, it's how well the engine block and crankshaft are machined (cylinder bored straight, crank journal reground to OEM specs, cleanliness of the parts and work area, etc.), that determines how well and how long internal engine parts will hold up. Don't blame shoddy workmanship on shoddy parts.

What Makes Engines "Rev Up" When Accelerated?

The throttle plate in the carburetor or throttle body (fuel injection) is nothing but an air valve. When it's opened up, the piston(s) draws in more air (and fuel) into the combustion chamber(s), and this builds up more air pressure, makes higher compression, which in turn allows the engine to produce more power and increases the RPM. But with the engine idling, the air pressure in the combustion chamber(s) is very low. This is why and how an engine idles slowly and won't produce much power at idling speed. Therefore, all engines produce more power and torque at higher RPM.

Important Information About Kohler Crankshafts -

Crankshafts, rather being made of steel or cast iron, and despite how well-balanced the rotating parts are in a pulling engine, suffer a lot of vibration at very high RPM in a single cylinder engine. Therefore, if possible, before purchasing a used crankshaft, it's best to look it over for hairline cracks with a strong magnifying glass or better yet, a powerful microscope. And as the saying goes about buying anything off of eBay: BUYER BEWARE! So ask for a money-back guarantee, or you may have nothing but a piece of scrap metal on your hands.

Identifying Kohler Crankshafts -

• To identify the 10, 12, 14 and 16hp Kohler crankshafts, the 10hp cranks have a shorter stroke than the other cranks. You can compare a 10hp crank to a 12, 14 or 16hp crank by placing them side by side, and with the counter weights down, looking at the bottom part of the rod journal, the journal on the 10hp will be closer to the main journals. (3/8" of difference in stroke.)
• The K301 and M12 crankshaft is balanced differently from the 14 and 16hp cranks because the counter weights are machined off for the lighter-weight K301 and M12 piston assemblies. NOTE: Some 10hp cranks also have the counter weights machined off like the K301 and M12 cranks and some don't.
• And the K321, M14 and 16hp cranks are identical in weight and appearance. Some may have a few more holes drilled into the counter weights, but that's the only difference.
• If you have the engine's original model and specification numbers, you can find the correct part number, dimensions and specifications of the crankshaft here: CRANKSHAFT REFERENCE MANUAL. (Open with Adobe Acrobat Reader and use Google Chrome web browser for a faster download of web sites with large files.)

How to Remove Only the Crankshaft from a Kohler Engine -

1. Remove the flywheel and anything that's on the PTO end of the crankshaft.
2. Remove the cylinder head.
3. Remove the oil pan.
4. Remove the piston/connecting rod assembly from the engine block.
5. Remove the bearing plate.
6. Finally, being very gentle, bump the PTO end of the crankshaft with a 2 lb. brass head hammer or a 2-3 lb. steel hammer and wooden block to remove it from the engine block.
7. And if an engine originally came with balance gears, there's no need to reinstall them. They're made of out-of-balance cast iron material, they serve very little purpose and they may break, possibly destroying the engine block.

Here's Something Important To Keep In Mind About A Reground Crankshaft Journal -

Sometimes as the rod journal (crank pin) wears, it will develop a "flat spot" at a certain place when the piston is at the ATDC position on the compression stroke. The combustion process place the most pressure on the piston and connecting rod at this particular point, which squeezes the oil out between the rod bearing surface and crank journal, causing brief metal to metal contact. As this happens, this point wears more than the rest of the journal, causing the journal to become oval or "egg shaped." Sometimes the upper part of the connecting rod will wear as well, but in most cases, it's the part that moves the most that wears more, which is the crank journal.

When regrinding a journal, and if a STD size journal is not worn past .005" on the low side or on the "flat spot," then the crank grinder person can regrind it "centered"-the next undersize, which is .010", or if he gives it an extra .001" of additional oil clearance, it'll have a .011" undersize journal and the crankshaft will retain it's original stroke. But if a standard size journal is worn .006" or more, then the crank grinder person can manipulate the grinding process by regrinding the journal to the next undersize by offsetting the journal .006" or more in the lathe and regrind it to .010" instead of .020" undersize, or .020" instead of .030" undersize, depending on the size of the journal. By doing this, and depending on the amount of wear the journal had and the location of the low side or "flat spot," the crankshaft will have a slightly longer or shorter stroke. Otherwise, if the severely worn journal were to be reground "centered," it would have to go to .020" undersize, and the stock stroke will be retained. The decrease or increase of the stroke on a crankshaft with a worn STD, .010" or .020" journal can vary from .001"-.005". and as much as .010" on a STD size journal that's been reground to .020" undersize or even .015" on a STD size journal that's been reground to .030" undersize! So when a pulling association/club sanctioning rules and requirements state that an engine must have the stock factory length stroke, and if a crankshaft was reground, it may actually have a slightly longer or shorter stroke.

Something to take into consideration is this: Depending who regrind the crank journal undersize, the stroke can be offset more or less by .005". Some grinders like to "center" an excessively worn journal so it can be ground to the next undersize.

FYI - Oil clearance is the distance between the connecting rod bearing surface and crank journal. A thin coat of oil is supposed to keep all moving parts inside an engine from making contact with each other. If there's too little oil clearance between the rod and crank, especially in a high RPM engine, the rod will swell due to excessive heat, and then the rod will make contact with the crank and burn on the journal. If there's too much clearance, the rod will knock and possibly break at high RPM, which could destroy the entire engine block.

Stroking a Stock-Stroke Crankshaft -

Virtually any machine shop that regrind crankshafts can weld up the rod journal and regrind it to give it a slightly longer stroke. (Click or tap here for an explanation of why a longer stroke works better.) But keep in mind if thinking of doing this, that if using a stock-length connecting rod with a stock compression-height piston, the piston will pop out of the cylinder half the distance that was added to the stroke on the crank journal. The piston could hit the cylinder head. Also, grinding the center of the [stock] camshaft may be required for clearance of the connecting rod swing due to the longer stroke. And notching of the cylinder wall on each side of the rod swing for clearance may be required to prevent the rod from striking the lower part of the cylinder wall. Finally, the oil dipper on the rod cap may need to be shortened to prevent it from hitting the bottom of the oil pan.

But if building a stock engine at 4,000 RPM for more power and torque, it'll be better and less cost effective to use a stock stroke crankshaft, and install a reground low-RPM torque cam to give the engine a little more muscle. Performing a professional valve job to increase the air flow and milling of the head will help the engine to pump out a few more ponies, too.

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Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website.
Replace damaged or broken off threaded stud on flywheel end of crankshaft with installation of... 3/8" or 7/16" UNF grade 8 bolt. $75.00 each, plus return shipping & handling. 7/16" or 5/8" UNF hardened threaded stud. Resembles original stud on end of crankshaft. $75.00 each, plus return shipping & handling. Center drill and cut threads in PTO end of crankshaft for installation of 3/8" UNF grade 8 bolt. $75.00 each, plus return shipping & handling. Crankshaft Regrinding - This service includes all makes and models of small engine crankshafts. Regrind single cylinder engine crankshaft rod journal to next undersize. $100.00 each, plus return shipping & handling. Regrind V-twin engine crankshaft rod journal to next undersize. (Both rods on the same journal.) $175.00 each, plus return shipping & handling. Regrind opposed twin cylinder engine crankshaft rod journals to the next undersize. (Two separate journals.) $200.00 for both journals, plus return shipping & handling. NOTE: Kohler K241-K361 crankshafts can be reground to .030" undersize and still be safe to use with the connecting rod bored for installation of matching undersized replaceable bearing inserts. And all crankshafts, rather if they're automotive or small engine, are checked for straightness before grinding. If they're bent or twisted, sometimes they can be straightened. We also offer offset crankshaft grinding to increase the length of the stroke at no extra charge. NOTE: Once installed and in operation, there is no warranty or guarantee of any kind on crankshaft regrinds. YouTube video: Single cylinder crankshaft regrind. [Return To Previous Paragraph, Section or Website] "Round Up" Crankshaft Rod Journal(s) and Resize Connecting Rod(s) - This service is for most makes and models of small engines when an undersize connecting rod or bearing inserts isn't available, if the crankshaft is worn beyond .010" and needs to be reground again, the journal can be reground to wherever it "cleans up" or is true again, then the connecting rod can be resized so it'll fit the smaller undersize journal with the factory recommended .0025" oil clearance. To resize the rod so it'll fit to a few thousands of an inch smaller diameter crank journal, first, metal is removed from the mating end of the rod cap, then the cap is fasten to the rod. The big hole in the rod is now oblong or "egg shaped." Then the big hole in the rod is honed until it's .002" larger than the diameter of the crank journal. Honing reshapes the hole into a perfect circle again, only smaller in diameter. This works very well and it lasts as long as an ordinary STD size rod and crank journal. This can only be performed on a rod with a good bearing surface. It cannot be done on a burnt or heavily scored connecting rod because too much metal would need to be removed. If you're interested, we will need your crankshaft and connecting rod(s). NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. NOTE: Once installed and in operation, there is no warranty or guarantee of any kind on crankshaft regrinds. YouTube video: Single cylinder crankshaft regrind. Regrind/Round-up single cylinder engine crankshaft journal and resize rod to fit the "odd-size" journal. $150.00 each, plus return shipping & handling. Regrind/Round-up V-twin engine crankshaft and resize two rods to fit the "odd-size" journal. (Both rods ride on the same journal). $275.00 each, plus return shipping & handling. Regrind/Round-up opposed twin cylinder engine crankshaft and resize two rods to fit the "odd-size" journals. (Two separate journals.) $300.00 for both journals, plus return shipping & handling. [Return To Previous Paragraph, Section or Website] Precision Dynamic Spin-Balance Service - If your engine vibrates a lot or more than normal, and if the parasitic accessories or attachments are not broken or out-of-balance, then chances are, the rotating assembly (crankshaft, connecting rod and piston assembly, and/or flywheel) needs to be precision balanced. Dynamically Spin-Balance Kohler K241, K301, K321, K341 or K361 cast iron flywheel. $110.00± each labor, plus return shipping & handling. Dynamically Spin-Balance Kohler K90/K91, K141, K160/K161, K181, M8, K241, M10, K301, M12, K321, M14, K341, M16 or K361, or virtually any other make and model of single cylinder small engine factory crankshaft with OEM or billet connecting rod and matching (OEM or aftermarket/high performance) piston assembly. $330.00± per rotating assembly, plus return shipping & handling. NOTE: ± means more or less. See important message below. Prices are subject to change without notice. IMPORTANT --> Due to clumsy, incompetent and uncaring "gorilla" workers that may have a tendency to damage heavy items while handling packages at a shipping center, for better protection, please ship your crankshaft, connecting rod and piston assembly, and/or flywheel to A-1 Miller's address to be balanced, please enclose the items in two 12-1/4" x 12-1/4" x 6" USPS Large Flat Rate Boxes. Place one box inside the other to double the strength. Use one double-box to ship the crankshaft, connecting rod and piston assembly, and use another double-box to ship the flywheel only, and place rigid packing material under, around/between and over the parts to prevent damage during shipment. But for heavy items, ship delicate/fragile parts in a sturdy wooden crate with sufficient packing/stuffing under, around/between and over the parts. Include a note in the package or crate with your contact information and a description of what you want done. Or if you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's shop to personally purchase parts, or drop off and/or pick up your carburetor, clutch assembly, engine parts, entire engine, transmission, transaxle, entire garden tractor, small motorized vehicle, etc., for repairing and/or rebuilding. "The road to a friend's house (or shop) is never long." Don't sacrifice quality workmanship for distance. [Return To Previous Paragraph, Section or Website]
Balance Gear Needle Bearings. For believers in using balance gears. Fits Kohler engine models K241, K301, K321, K341, K361, M10, M12, M14 and M16. Fits Kohler engines with serial number before 9641311 (early 1979 and older). Fits old style balance gears with .6825"-.6828" center hole. OEM Kohler part # 236506-S. $53.70 each, plus shipping & handling. Fits Kohler engines with serial number after 9641310 (late 1979 and newer) . Fits new style balance gears with .6870"-.6875" (11/16") center hole. OEM Kohler part # 47 030 01-S. $18.30 each, plus shipping & handling.
High Quality 8 Ball Main Crankshaft Radial Bearings. Fits Kohler K-series and Magnum cast iron block engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. Heat treated chrome steel (AISI 52100) for higher resistance and durability. Supports up to 17,000 RPM. Works excellent for general lawn and garden engines or for high performance competition pulling engines that run at open RPM. FYI - The 8 ball roller bearings have larger diameter balls than the aftermarket 12 ball roller bearings, that have smaller balls. Therefore, the balls in the 8 ball bearings rotate slower, causing less friction. They run freer and more cooler. In theory, it seems that the 12 ball bearings would work better in an open throttle pulling engine, but in reality, it's a different story. Dimensions: 1.57" (40mm) I.D. x 3.54" O.D. (90mm) x .90" (23mm) width. See note below Ê. NOTE: If your bearing(s) have more than .005" of play due to wear, or it feels rough or "rubbles" when rotated by hand with motor oil applied, then it should be replaced. FYI - All US and import manufacturers of ball bearings have always been made them to the metric dimensions. Where applicable, the manufacturers try to make them close as possible to the inch dimensions. Used and in excellent condition. OEM Kohler bearing with very little to no wear. OEM Kohler part # 235376-S. $5.00 each, plus shipping & handling. (When available.) New high quality aftermarket. A-1 Miller's part #150973. Replaces Kohler part # 235376-S. $22.00 each, plus shipping & handling. New. OEM Kohler part # 235376-S. $116.55 each, plus shipping & handling.
A-1 Miller's Crankshaft Machine Repair Service - (Added 2/3/21) Drill and tap flywheel end of Kohler K-series crankshaft for installation of 3/8" bolt when threads on integrated 5/8" stud are damaged beyond rethreading or when 5/8" stud breaks off. No need to purchase another high-dollar, hard to find crankshaft. Precision work performed in large metal lathe. Hardware include: 3/8-24 UNF grade 8 bolt, split lock washer and 3/8" x 5/8" step washer adapter. $75.00 for parts and labor, plus return shipping & handling. Drill and tap PTO end of Kohler crankshaft for installation of 3/8" bolt to retain electric PTO clutch or billet starter pulley. Precision work performed in large metal lathe. Hardware includes: 3/8" grade 8 bolt, split lock washer and extra thick flat washer. $45.00 for parts and labor, plus return shipping & handling. Drill and tap flywheel end of Kohler K-series crankshaft for installation of 5/8" threaded steel stud when threads on integrated 5/8" stud are damaged beyond rethreading or when 5/8" stud breaks off (too short). No need to purchase another high-dollar, hard to find crankshaft. Precision work performed in large metal lathe. Hardware includes: Installation of 5/8-18 UNF stud, self-locking flywheel retaining nut and extra thick flat washer. $75.00 for parts and labor, plus return shipping & handling.
Flywheel Retaining Nuts for 5/8" or 3/4" threaded stud on end of Kohler K-series and billet steel crankshafts. IMPORTANT: Apply thin coat of motor oil on threads of crankshaft before installing nut, then torque each nut to 65 ft. lbs. Nylon Insert Self-Locking Nut. 5/8-18 UNF (fine thread) threads. Replaces discontinued Kohler part # 25 100 02-S. $2.50 each, plus shipping & handling. Nylon Insert Self-Locking Nut. 3/4-16 UNF (fine thread) threads. Used on early K241 crankshafts and most billet steel crankshafts. Replaces discontinued Kohler part #'s X-89-11, X-119-16. $3.00 each, plus shipping & handling.
Flywheel Retaining Bolt and Washer Kit. Fits Kohler and various other makes and models of small engines with a 3/8" threaded hole in flywheel end of crankshaft. Includes: 3/8-24 UNF grade 8 bolt, split lock washer and extra thick flat washer. IMPORTANT: Apply thin coat of motor oil in threads of bolt, then torque to 40 ft. lb. High quality aftermarket. Replaces OEM Kohler part #'s 25 068 04, 25 068 24, 47 086 16, 47 086 18, 52 068 25 (bolt) and 12 468 03-S, 52 114 02, 52 468 15 (washer). $5.00 per kit, plus shipping & handling.	Safety Retaining Bolt and Washer Kit for Starter Pulley on PTO end of crankshaft or Harmonic Balancer on automotive crankshaft (mini rod). Prevents starter pulley or harmonic balancer from dislodging on crankshaft, and becoming an airborne projectile, which can cause serious injury to a bystander or spectator. Kit includes: 3/8-24 UNF or 7/16-28 UNF grade 8 bolt, split lock washer and 1-3/8" O.D. flat washer. Please indicate if you need the kit for a 3/8" or 7/16" bolt. A-1 Miller's aftermarket parts. $5.00 per kit, plus shipping & handling.
Extra Thick Flywheel / Aluminum Hub Adapter Retaining Washers. A thick, wide washer is a must to secure flywheel and prevent clutch/driveshaft aluminum hub adapter breakage. Each made of steel and measures 1-1/4" O.D. x approximately 1/4" thick. Washers with 13/32" center hole. To be used with a crankshaft that has a 3/8" bolt, and/or aluminum hub adapter that has a 3/8" center hole. Fabricated A-1 Miller's part. $3.00 each, plus shipping & handling. OEM Kohler part #'s 12 468 03-S. $3.80 each, plus shipping & handling. Washer with 5/8" center hole. To be used with a crankshaft that has a 5/8" stud, and/or aluminum hub adapter that has a 5/8" center hole. Fabricated A-1 Miller's part. Replaces discontinued Kohler part # X-25-104. $5.00 each, plus shipping & handling. Washer with 3/4" center hole. To be used with a crankshaft that has a 3/4" stud, and/or aluminum hub adapter that has a 3/4" center hole. Fabricated A-1 Miller's part. Replaces discontinued Kohler part # X-25-71. $5.00 each, plus shipping & handling.
Step Washer Adapter. Use this part to center the OEM Cub Cadet or OEM John Deere cast aluminum clutch hubs, or the billet aluminum clutch hub with a 5/8" hole to a crankshaft with the 3/8" bolt on Kohler later model K-series and all Magnum engines. Professionally machined by A-1 Miller's to fit inside factory cast aluminum hub adapters. A must to prevent severe wobble/vibration and prevent hub breakage and/or driveshaft/clutch breakage. [Return To Previous Section, Paragraph or Website] $30.00 each, plus shipping & handling.
Cub Cadet garden tractor hub adapters with 5/8" center hole (early K-series), w/pulley, w/dowel pin. Used and in excellent condition. OEM Kohler part # 41 071 03-S. $60.00 each, plus shipping & handling. (When available.) New. OEM Kohler part # 41 071 03-S. $90.73 each, plus shipping & handling. New. OEM Cub Cadet part # KH-41-071-03. $116.30 each, plus shipping & handling. New. OEM Cub Cadet part # 759-3287. $204.00 each, plus shipping & handling. Cub Cadet garden tractor hub adapters with 5/8" center hole (early K-series), w/o pulley, w/dowel pin. Used and in excellent condition. Discontinued Kohler part # 41 071 05-S. $60.00 each, plus shipping & handling. New. OEM Cub Cadet part # KH-41-071-05. $204.00 each, plus shipping & handling. Cub Cadet garden tractor hub adapters with 3/8" center hole (later K-series, all KT-series and Magnum), w/o pulley, w/dowel pin. Used and in excellent condition. $40.00 each, plus shipping & handling. (When available.) New. OEM Kohler part # 52 755 61-S. $115.55 each, plus shipping & handling. 1/4" diameter x 3/4" length hardened steel dowel pin for OEM Kohler and billet aluminum hub adapters. Secures aluminum hub to flywheel to prevent slippage. Replaces Cub Cadet part # KH-X-56-7 and Kohler part # X-56-7. $1.50 each, plus shipping & handling.
Square Aluminum Flywheel/Crankshaft Key. Made of 6061 medium-grade hardness alloy aluminum. Fits Kohler engine models K141, K160/K161, K181, L181, M8, K241, K301, K321, K341, K361, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20 made in 1973 and later. Helps prevent damage of keyway in crankshaft and/or prevents the possibility of cracking/breaking of factory cast iron flywheel due to sudden crankshaft lock-up in the event of connecting rod failure. Dimensions: 3/16" square x 1-3/8" length. IMPORTANT: Thoroughly clean tapers inside flywheel and on crankshaft before installing flywheel! A-1 Miller's part. Replaces Kohler [steel key] part # X-286-17-S. $5.00 each, plus shipping & handling. Rectangular Steel Flywheel/Crankshaft Key. Fits Kohler engine models K241, K301 and K321 made in 1972 and earlier with the 8" diameter flywheel and starter/generator. Also fits Kohler engine models K330/K331. Dimensions: 3/16" wide x 1/4" tall x 1-3/8" length. IMPORTANT: Thoroughly clean tapers inside flywheel and on crankshaft before installing flywheel! Used and in excellent condition. Discontinued Kohler part # X-366-1-S. $5.00 each, plus shipping & handling. (When available.) Square Steel Flywheel/Crankshaft Keys. Fits Kohler engine models K141, K160/K161, L160/L161, L181, K181, M8, K241, K301, K321, K341, K361, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20 made in 1973 and later. Dimensions: 3/16" square x 1-3/8" length. IMPORTANT: Thoroughly clean tapers inside flywheel and on crankshaft before installing flywheel! High quality aftermarket. Made of mild steel. Replaces Kohler part # X-286-17-S. $1.00 each, plus shipping & handling. OEM Kohler part # X-286-17-S. $2.10 each, plus shipping & handling. Woodruff (Semicircular) Steel Flywheel/Crankshaft Key. Fits most OHV aluminum block Kohler engines. Dimensions: 3/16" wide x 5/8" length. IMPORTANT: Thoroughly clean tapers inside flywheel and on crankshaft before installing flywheel! High quality aftermarket. $1.00 each, plus shipping & handling. OEM Kohler part # X-42-15-S. $1.70 each, plus shipping & handling. Woodruff (Semicircular) Steel Keys for Flywheel/Crankshaft and Gear Reduction Shaft on certain Kohler engine models K241, K301, K321, K341, and all Kohler Magnum models M10, M12, M14, M16, and models CH13 and CH15. Dimensions: 3/16" wide x 1" length. IMPORTANT: Thoroughly clean tapers inside flywheel and on crankshaft before installing flywheel! High quality aftermarket. $1.00 each, plus shipping & handling. OEM Kohler part # X-46-3-S. $2.25 each, plus shipping & handling.

Grinding a Crankshaft Journal -

Grinding a crank journal is performed in crankshaft grinder machine. It's actually much easier to grind a journal on a single cylinder small engine crankshaft than it is to grind a crankshaft with multiple journals. It takes a lot of skill and full attention when regrinding crankshaft journals. Basically, what the crankshaft grinder machinist needs to do is...

1. Make sure the grinding stone is precision trued-up so it won't leave skip marks on the journal(s).
2. On a single cylinder crankshaft, clamp one of the main journals in the first chuck, then clamp the other main journal in the second chuck to make sure the crankshaft is perfectly centered in the first chuck, then loosen the second chuck and move it away from the crankshaft.
3. If it's a multiple journal crankshaft, perform the above È with the crankshaft firmly clamped in both chucks.
4. Firmly tighten the chuck(s).
5. Relocate the first chuck (for a single cylinder crankshaft) or relocate both chucks (for a multiple journal crankshaft) off-center according to the crankshaft's stroke.
6. Set up the dial indicator, and position it's lever on the #1 journal.
7. Rotate the crankshaft slowly by hand until the lowest area on the journal shows on the dial indicator and then zero in the dial indicator.
8. Relocate the first chuck (for a single cylinder crankshaft) or relocate both chucks (for a multiple journal crankshaft) off-center according to the crankshaft's stroke.
9. If it's a multiple journal crankshaft, position the steady rest in the center main journal to prevent flexing of the crankshaft when grinding.
10. Slowly and very carefully grind each journal to the next undersize until it's within .0001" of specs. But the grinder machinist needs to stop midway of grinding and carefully measure the journal(s) with a micrometer (the dial or digital calipers are not as accurate) from time to time so the journal(s) will grind within specs. Once metal is removed, it's hard to replace. If a journal is ground undersize too much, it can be reground to the next undersize, or if it's already reground to the maximum undersize, it can be welded up 360°, then reground back to STD size, or to the undersize of the other journals. But welding a journal and then grinding it can be very expensive! And the crankshaft's stroke may not be the same because due to the build-up of welding, it'll be hard to find the true centerline of the journal.
11. Back the stone away, and finish polishing the journal with a crankshaft polisher. The polishing process will remove the roughness of the grinding stone and about .0001" of metal until the journal is within specs.

The standard (STD) size rod journal (crank pin) on Kohler's K241, M10, K301, M12, K321, M14, K341 and M16 flatheads, K361 and the M20, MV20 opposed twin cylinder engines measures 1.500" on the "high side", and 1.499" on the "low side" (maximum wear limit). If an engine is going to run no faster than 4,000 RPM (either for general lawn and garden use, snow removal or competition pulling), then it should be safe to have a worn rod journal reground on the high side. The grinder person will grind the journal(s) as follows:

• .010" undersize, which will measure 1.490" for a .010" undersize aluminum bearing surface connecting rod or a connecting rod with .010" bearing inserts.
• .020" undersize, which will measure 1.480" for a connecting rod with .020" bearing inserts.
• .030" undersize which will measure 1.470" for a connecting rod with .030" bearing inserts.

But when having a worn rod journal reground for an engine that's going to run at open RPM for competition pulling, it'll be a good idea to indicate this to the crank grinder person by writing on one of the counterweights the words LOW SIDE with a bright-colored paint marker (TEXPEN®). The grinder person will then grind the journal(s) as follows:

• .011" undersize, which will measure 1.489" for a .010" undersize aluminum bearing surface connecting rod or a connecting rod with .010" bearing inserts (recommended).
• .021" undersize, which will measure 1.479" for a connecting rod with .020" bearing inserts.
• .031" undersize which will measure 1.469" for a connecting rod with .030" bearing inserts.
• The additional .001" of [oil] clearance is to prevent overheating and scoring of the plain aluminum connecting rod or bearing inserts and/or rod journal at open RPM.

NOTE: If the word RACE is written on a crank for additional oil clearance, some crank grinders will still grind a journal on the low side and add an additional .001". Which will make the journal .012", .022" or .032" undersize. So RACE should only be used on a journal that's going to be reground on the high side, which will provide the same clearance as having a journal reground on the low side. And by the way - the additional .001" of clearance (with either LOW SIDE or RACE) will not cause the rod to make a knocking sound. Click HERE for Complete Kohler Single Cylinder Engine Specifications and Tolerances.

The heat-treating or hardening process that Kohler use on the rod journal area obviously goes deep into the crank. Because it's been proven that when the journal is ground for an undersize bearing insert, a .010", .020" or even a .030" undersize insert can be used with no problem. Myself and many other pullers use undersize bearing inserts in our pulling tractors, and I have no problems with the crank journal wearing whatsoever. Heck, I've been using a .020" undersize bearing inserts with the same crankshaft in our 30 c.i. tractor for 5 years and in about 75 pulls, and the crank journal hasn't worn at all. Most crank journals wear because of dirty motor oil or the wrong viscosity of oil is used. Not because of "soft metal" in the journal. Actually, the bearing material is not supposed to make contact with the crank journal. They're supposed to be kept separate by clean motor oil. And as far as cast iron Kohler crankshafts breaking is concerned, an undersize journal shouldn't make a cast crank break. I've always seen them break next to the journal, not in the journal area. As with anything, crankshafts break because something makes them break. Either out-of-balance parts, dirty flywheel taper/crankshaft taper or a manufacturing defect makes a crankshaft break.

By the way, a crank journal that's been turned .030" undersize will help to produce slightly more RPM and horsepower because there's less bearing surface to cause friction. Some NASCAR engineers do this to their racing engines. It works.

If you have a crankshaft that's made for a special purpose, and it has a worn .030" journal, and that particular crankshaft is no longer available, well, the journal can be welded up and reground back to STD size. Here's one place who can do this for you: Big 2 Engine Rebuilders, Inc., 3214 25th Ave., Gulfport, MS 39501-5909 Phone: 228-863-5425 FAX: 228-868-8728. Ask for Pete Bloss.

About Crankshafts Breaking at Open RPM -

A cast or billet steel crankshaft should survive as high as 7,000 RPM for a long time if they've been precision-balanced to the connecting rod and piston assembly using a dynamic balancing machine. Some cast cranks break, and steel crankshafts are prone to breaking, too. When they do break, it's usually due to: being in an engine that broke the connecting rod and the rotating assembly came to a "sudden stop", and the flywheel kept wanting to spin, but cracked the crank instead; an out-of-balance flywheel; and/or an out-of-balance starter pulley on the PTO end (which should also be precision-balanced). An out-of-balanced flywheel or pulley will cause the crankshaft to flex a few thousands of an inch at open RPM. When they flex, the "bending of the metal" causes metal fatigue, which creates a microscopic crack next to the rod journal, and they eventually break. Kind of like bending a piece of wire back and forth by hand, until it eventually breaks. We heard that the Kohler Magnum crankshafts are tougher than the early K-series cranks when precision-balanced. And when a crankshaft breaks at open RPM, it can also break a cast cam or bend a billet steel cam, which could crack the engine block at the cam pin on the flywheel side.

How to Get More Power Out of a Stock Engine -

It takes three things to make an internal combustion engine run: compression (air pressure within the combustion chamber), carburetion (fuel in the carburetor) and ignition (spark). The engine needs to have sufficient compression to fully compress the air/fuel mixture to make adequate power. Fuel needs to get to the carburetor and then into the combustion chamber. And the ignition needs to be strong enough to ignite the air/fuel mixture. The ignition timing must also need to be set correctly to ignite the air/fuel mixture precisely at 20° BTDC (Kohler) to take full advantage of the exploding gases. Actually, it takes four things to make an engine run, including the starting system. If an engine won't crank over or if it cranks over slowly (with an electric starter motor), and it has adequate compression, the carburetor and ignition seems to be working fine, then the only thing left is the starting system. Perhaps the starter motor or battery is going bad. They probably appear to be operating normal, but maybe one or the other isn't cranking the engine over fast enough to produce adequate compression to start the engine. I've seen this happen a few times. But if the compression, carburetion or ignition is weak or defective, power will be decreased dramatically. When checking for loss of power, always check the following things:
Check the ignition timing. If the timing is retarded or over advanced, the engine will lose power and run sluggish. Check for a worn points lobe on the camshaft, too.
Carburetion is when the adequate amount of fuel and air mixture enters an engine smoothly.
Compression is when the air/fuel mixture is adequately pressurized in the combustion chamber on the compression stroke. The secret to gaining more horsepower and torque is increase the compression ratio and improve the air flow in and out of the combustion chamber.
Another way to gain more power from the high RPM is to install a special camshaft along with larger diameter valves, professional valve job, stiffer valve springs and enlarge intake and exhaust port runners.
Apply J-B Weld (apply at room temperature, allow to fully cure in 24 hours) inside the intake port and smooth it so the air will flow without any restrictions into the combustion chamber. This works great. But before applying the J-B Weld, make sure the port is absolutely clean or the J-B Weld will not bond to the engine block.
and a few other things that's mentioned elsewhere in my pulling tips web sites.

FYI - When everything that's mentioned here is performed to an engine, it should produce maximum power. But if just a few things are performed, the power will be increased, but not to the maximum. For example: if a quality valve job is performed, then the intake and exhaust runners would also need to be enlarged, and the carburetor would need to be bored to take full advantage of the maximum airflow. But if the intake runner isn't enlarged, this would create a "bottle neck," and air will be restricted. The same goes for the valves and carburetor. Also, if a cam with more duration is installed, then the valve and air intake system would need to be maximized to take full advantage of the performance camshaft. But if just the cylinder head is milled, and nothing else is done to the engine, this alone should add a few ponies to an engine. The same goes when just popping the piston out of the cylinder. Each time a performance thing is done to an engine, power output will be increased. But if a series of things are performed, such as maximizing the air intake system, they can work together for better engine performance.

When it's time to put more muscle in an engine...

In order for an engine to turn at extremely high RPM (6,000+), the compression ratio and air flow in and out of the combustion chamber must be increased to the maximum. The secret to increased engine performance is to get as much air (and fuel) into the combustion chamber, and get it out as quickly as possible. (Remember - engine performance is entertainment to the spectators.) For the compression ratio to be increased, the air entering the combustion chamber must be squeezed as tight as possible.

The only things that can cause an engine to overheat and loose power are as follows:

• Clogged cooling fins or broken fins on the flywheel
• Too high compression ratio for the grade/octane of gas being used
• Ignition timing advanced too much
• Lean fuel mixture
• Vacuum leak at the carburetor, which will also cause a lean fuel mixture.

Get Maximum Horsepower and Torque from a "Basically Stock" Kohler 10-16hp K-series or Magnum Engine -

Approximately 48% more horsepower and torque can be produced from a basically "stock" single cylinder flathead Kohler engine. This means that approximately 15hp can be produced from a 10hp, 17hp from a 12hp, 20hp from a 14hp and 23hp from a 16hp governed engine at 4,000 RPM (the factory setting of maximum RPM for virtually all small gas engines, including all of Kohler engines is 3,600) on Premium gasoline! And if a steel flywheel is used, this will add more torque to a 4,000 RPM pulling engine! Also, about 10% to 13% more power can be produced with E-85 or methanol fuels! Click or tap here for information regarding E-85 fuel. And even more power can be produced above 4,000 RPM! But be sure to install a billet steel flywheel, connecting rod and scatter shields whenever running an engine above 4,000 RPM! The compression ratio must be increased in order to increase the power output. Click or tap here for references to various compression ratios. After modifications have been made, the increase in power will definitely be noticeable!

(Added 3/3/21) To increase the compression ratio on a Kohler engine model K241, M10, K301, M12, K321, M14, K341 or M16, mill the head just until the ridge is gone. And if also decking the block, remove only enough metal where the highest part of the valve seats will not be interfered with. Higher compression ratio means more horsepower and torque, which means a more efficient engine. High octane gas may need to be used to prevent harmful pinging and detonation.

• For a K241 and M10 engine, depending on which type of factory head is used, the compression ratio is 5:1, 5.4:1 or 7.1:1. But with the head milled and block decked, add approximately 1.3:1 to each head used.
• For a K301 and M12 engine, depending on which type of factory head is used, the compression ratio is 6.2:1, 6.6:1 or 8.6:1. But with the head milled and block decked, add approximately 1.4:1 to each head used.
• For a K321 and M14 engine, depending on which type of factory head is used, the compression ratio is 6.6:1, 7.3:1 or 9:1. But with the head milled and block decked, add approximately 1.5:1 to each head used.
• And for the K341 and M16 engines, with the factory head, the compression ratio is 7.3:1. But with the head milled and block decked, add approximately 1.6:1. If using a machined billet head, the compression ratio is about 9:1. But with the block decked, it be approximately 9.75:1.

For competition pulling only, remove or disable the operation of parasitic accessories from the engine (which robs horsepower and causes drag on the engine), such as the starter/generator or alternator charging system, and including reducing the height of the fins by about 3/4 on the flywheel. Click or tap here to learn how to do this. And depending on battery drainage and need for recharging, to be precise, and with the engine running at 3,600 RPM, the generator part of the starter/generator unit or alternator stator use about 3/8hp (of engine power) when it recharges a fully discharged battery at full 15 amps; about 5/8hp at full 20 amps; and about 7/8hp at full 30 amps. But if the battery doesn't need much recharging, the charging system draws less hp from the engine. We know this small amount isn't much, but every hp counts in competition pulling. So to reserve this power for pulling, disconnect the generator or alternator from charging the battery (and powering other accessories as well) simply by splitting the wire that connects to the FIELD terminal (the smaller wire and terminal) on a s/g unit and splitting the wire that connects to the center terminal on the voltage rectifier/regular of an alternator system. Then connect an ordinary OFF/ON toggle switch in that wire or circuit to turn off and on the charging current. And it'll be best not to spin the s/g when pulling. Being it has radial ball bearings, the excessive spinning won't hurt it. But being the V-belt causes drag, depending on belt tension, it can use up to 2hp of engine power just to spin it. This is also power that can be put to the rear tires for pulling. Besides, wouldn't it be better to spin the tires than the starter/generator? So to disengage the s/g belt, install threaded studs with locknuts on the s/g bracket and install a heavy spring on the s/g so it'll remain close to the engine. To crank the engine, install the belt on the pulleys, then pull out on the s/g with a fabricated handle to tighten the belt. After the engine starts, release the s/g and flip the belt off. But use caution doing this for an obvious reason!

Briggs & Stratton, Tecumseh, Onan and Kohler's cast iron block 7hp and 8hp, and the opposed twin cylinder flathead engines are all somewhat limited on what can be done to boost their horsepower and torque. These engines are built from the factory to produce as much power as they possibly can, and still run safely on low octane gasoline. Therefore, very few modifications can be perform to help increase the power output. The only alternative is to use a bigger engine.

The increase in the compression will cause the combustion chamber to operate at a higher temperature. If low octane gas (87 octane) is used, and because low octane gas burns more rapidly than high octane gas, it'll burn hotter in a high compression engine, causing the piston and rings to overheat and wear out much sooner. Therefore, high octane gas (at least 91 octane [Premium]) must be used in a high compression engine because it burns slower and it maintains a cooler operating temperature within the combustion chamber. It'll help the engine last longer plus the high octane gas will help to produce more power. Also, it's safe to use just ordinary unleaded [high octane] gasoline with no additives (except what's already been formulated with the gasoline at the pump). Premium gasoline is the highest octane automotive gas you can get at your local filling station or convenience store.

High compression engines naturally operate at a higher operating temperature. So when using low octane gasoline (87 octane rating) in a high compression engine, the octane of the gas is reduced by 1 point for every 10º above the operating combustion chamber temperature that it is formulated for. This will cause the gas to burn faster and cause the engine to lose power. "Detonation" (pounding of the piston) could also occur. When trying to restart an overheated high compression engine on low octane gas, what is happening is the gas is burning quickly and entirely in the combustion chamber, and producing expanding heat before the piston reaches TDC, driving the piston back down in the cylinder before it reaches TDC. It'll cause the engine to "runt, runt" or momentarily make the crankshaft rotate in the opposite direction (but the weight of the flywheel prevents this from happening). Overheating could also crack the [cast iron] cylinder, shrink the piston, burn a hole in the piston (detonation) and weaken the expansion of the piston rings. Methanol fuel has an octane rating of 135. This is why methanol works best in high compression engines.

If you have a stock, low compression engine, then it won't benefit whatsoever from using high octane fuel. All it'll do is waste fuel (some of the fuel will go unburned and exit out the exhaust) and the engine won't develop full power, even with advanced timing. So it's best just to use low octane fuel for best performance.

In an ordinary engine that's built-to-factory-specs (with no modifications), it's OK to use just 87 octane gasoline. If you were to use high octane gas in a low compression engine, you'll just be wasting money and gas. Because some of the gas will go out the exhaust unburned, with no increase in horsepower whatsoever.

As a matter of fact, since 1969, ALL Briggs & Stratton flathead aluminum block engines are built-to-the-max at 3,600 RPM at the factory. This does not lessen the longevity of the engine. The B&S flathead opposed twin cylinder engines (and all B&S single cylinder engines) have a factory-installed performance-ground camshaft with increased duration/overlap. This is why the opposed twin cylinder engines produce a "lopey" sound at slow idle out the exhaust. (Lope, lope, lope sound.) There are very few improvements that can be made to B&S engines so they will produce more horsepower and torque at 3,600 RPM. Why Kohler didn't follow B&S's method of building engines, I have no idea.

If you need even more power, remember the old saying: "There's No Substitute for Cubic Inches!" (This is true only when the engine is naturally-aspirated, and not turbo- or super-charged.)

If you're running a K241 or M10 Kohler engine in a class that allow up to a K301 or M12 engine, there's no need to go out and acquire a K301 or M12 block, and then have all the fancy machine work that was originally done on the K241 or M10 block. Instead, a 10hp (K241 or M10) can be easily converted into a 12hp (K301 or M12) engine by having the cylinder bored for a K301 or M12 piston assembly. A K301 or M12 crankshaft with a K301, M12, K321, M14, K341, M16 or K361 connecting rod will need to be used.

NOTE: Certain K-series K241 Kohler engine blocks have K301 embossed in the casting on the PTO end, but the engine actually have a K241 (10hp) bore and stroke. Kohler used the K301 blocks for K241 engines when they ran out of K241 blocks to keep up with the demand from small engine equipment manufacturers. These particular blocks have a thicker cylinder wall and can be safely bored for a K301 or M12 piston (even up to .040" oversize), without making the cylinder wall too thin. They cannot be bored for a K321 or M14 piston though. Being the 10hp and 12hp engines appear virtually the same on the outside, the only way to truly tell if this block or engine is actually a 10hp or 12hp is to accurately measure the bore and stroke. The 10hp's STD bore is 3.250" and the stroke is 2.875". The 12hp's STD bore is 3.375" and the stroke is 3.250". And besides the K241 and K301 pistons being different, the K241 and K301 crankshafts and connecting rods are totally different. They will NOT interchange.

A K301 embossed block with the smaller K241 (10hp) 3-1/4" bore can be safely bored oversize for use with a larger K301 3-3/8" piston and rings assembly, connecting rod and crankshaft. The K301 embossed blocks are actually a K241 engine with the 10hp 3-1/4" bore, with a K241 piston and rings assembly, connecting rod and crankshaft. The only thing special about this blocks is they have a thicker cylinder wall, and they weren't used in any "heavy duty" specific application. What happened is on the production line at Kohler, when Kohler ran out of K241/10hp blocks, they grabbed some K301 blocks and bored them for use with a K241/10hp piston and rings assembly, connecting rod and crankshaft to fill the production of 10hp engines to their equipment manufacturer clients. But not all K301 embossed Kohler blocks are actually K241/10hp engines. Some are bored for a K301 3-3/8" piston and rings assembly, connecting rod and crankshaft, and therefore, are a true K301/12hp engine. To determine which block is which, the diameter of the cylinder bore must to be accurately measured, because there is no indications on the outside of the block to identify the engine size, unless it has the original flywheel shroud and adhered vinyl label or riveted metal tag with the engine model number.

How to Calculate the Horsepower of a Small Engine and Determine Its Model Number - [Top of Page]

To calculate the factory-rated horsepower (HP) of a small engine, for an average single cylinder flathead (valves in block) engine, divide the CID by 2.45, which will show the approximate HP (at 3,600 RPM), for an average two cylinder flathead engine, divide the CID by 2.41 x 2, which will show the approximate HP (at 3,600 RPM), and for the average over head valve (OHV) engine, divide the CID by 1.45 x 2 (for two cylinder engines), which will show the approximate HP (at 3,600 RPM). Once you know this, you can then determine the engine model number.

For the mathematical formulas below to work, have JavaScript enabled in your web browser. Or use a handy calculator , or use a pen or pencil and paper .

Convert Cubic Inch Displacement (CID) into Cubic Centimeters (CC)

Multiply the CID by 16.39 = Cubic Centimeters. (1 cubic inch = 16.3870641 cubic centimeters.) Example: 262.37 (CID) x 16.39 = 4300 CC. To convert CC back into CID: 1 cubic centimeter = 0.0610237 cubic inches. (1 cubic inch = 16.39 cubic centimeters)

How to Calculate the Compression Ratio of a Flathead or OHV Engine -

1. Acquire a flat piece of Plexiglas slightly larger than the cylinder head, and drill a small hole in it where the combustion chamber of the head is.
2. Acquire a large test tube with cubic centimeter increments.
3. Fill the test tube with brake fluid.
4. Make a note of how much brake fluid is in the test tube.
5. Seal the Plexiglas over the cylinder head with the head gasket that's going to be used on the engine. (Use silicone sealer)
6. Fill the combustion chamber with the brake fluid through the drilled hole.
7. Make a note of how many cubic centimeters of brake fluid it took to fill the combustion chamber.
8. Now calculate the cubic inches of the cylinder in the engine. Convert that figure into cubic centimeters.
9. Finally, divide the cubic centimeters of the cylinder by the cubic centimeters in the combustion chamber. This should give the exact compression ratio.

How to Create a 25.7, 27.7, 31.6 CID Hybrid Kohler Engine Model K261, K281 or K321 - To create a 25.7, 27.7 or 31.6 CID hybrid Kohler model K261 (Destroked 12hp), K281 (Destroked 14hp), or K321 (Destroked 16hp) engine, the parts to use are: K301, M12, K321, M14, K341 or M16 engine block. K301, M12, K321, M14, K341 or M16 piston/rings assembly. K241 or M10 stock connecting rod, or a 5.558" length machined billet rod. K241 or M10 crankshaft. This combination of parts will create a de-stroked K301, M12, K321, M14 or K341 Kohler engine. The K261 will use a K301 or M12 block; the K281 will use a K321 or M14 block, and the K321 will use a K341 or M16 block. NOTE: If an ordinary K241 block is bored for use with a K301 piston and rings, this would leave the cylinder wall about 1/8" thick, and the cylinder could separate from the crankcase resulting in an engine explosion on a cool night when the air is dense. Therefore, if a 10hp block is used, it's highly recommended that a cylinder restraint strap be installed to secure the cylinder to the crankcase. If the hybrid model K261 is built to the max at 4,000 RPM, it should produce about 16½hp and 23 ft. lb. of torque at 4,000 RPM. And if built to the max at open RPM with a high flow valve job, ported, big performance cam and bored-out and reworked 1.2" carburetor, it'll produce about 26hp at 7,500 RPM and 22 ft. lb. of torque at 6,000 RPM. If the hybrid model K281 is built to the max at 4,000 RPM with stock size valves, ported, quality performance torque cam and a bored-out and reworked 1.2" carburetor, it'll produce about 22hp and 28 ft. lb. of torque at 4,000 RPM. And if built to the max at open RPM with a high flow valve job, ported, big performance cam and bored-out and reworked 1.2" carburetor, it'll produce about 30hp at 7,000 RPM and 25 ft. lb. of torque at 6,500 RPM. If the hybrid model K321 (by the way - this is NOT for the original K321/14hp Kohler engine) is built to the max at 4,000 RPM with a quality valve job, ported, quality performance torque cam and a bored-out and reworked 1.2" carburetor, it'll produce about 25hp and 33 ft. lb. of torque at 4,000 RPM. And if built to the max at open RPM with stock size valves, ported, big performance cam and bored-out and reworked 1.2" carburetor, it'll produce about 36hp at 7,500 RPM and 30 ft. lb. of torque at 6,000 RPM. Here's how to make it happen: For installation of bearing inserts in the connecting rod, the big end will need to be bored .070" offset toward the wrist pin hole so the piston will come flush with the top of the block, or it can be bored .050" offset toward the wrist pin hole for a .020" piston pop-out. NOTE: If boring the rod didn't remove metal from the entire circumference of the hole, roughen the uncut portion with 60 grit sandpaper, apply J-B Weld (use at room temperature) to the uncut portion, allow the J-B Weld to fully cure (harden) in 24 hours, then resize the hole so it'll be a perfect circle. Otherwise, the bearing inserts will not fit the crank journal correctly. The wrist pin hole in the K241 or M10 rod will need to be enlarged to exactly .8755" for use with the K301, M12, K321, M14, K341 or M16 piston's wrist pin. Being a heavier piston assembly is to be used, the crankshaft (rotating assembly) will need to be rebalanced, or the engine will vibrate severely and possibly self-destruct. This means that weight will need to be added to the counterweights on the K241 or M10 crankshaft so the rotating assembly will be dynamically precision spin-balanced. Click here to learn how to statically balance an engine. Set the ignition timing as usual, at 20º BTDC. If building this type of engine for competition pulling, check your association/club sanctioning rules and requirements so this engine will be legal within its class!

How to Create a 36.7, 38.3, 39.5 or 40.8 CID Hybrid Kohler Engine Model K381 or K411 - This is considered "old school technology" by today's standards, but it still works great when an association/club engine pulling rules and requirements require that the engine have the stock stroke, but allowed a bigger bore. And if these engines are built right, they should be very competitive for Stock class pulling. Only the Chevrolet V8 (1968-1973) 307 and (1962-1969) 327 pistons will work for this application. The Chevy V8 265, 283, 305 (229 V6) or 350 (4.2 V6) pistons will not work. If this type of engine is operated at open RPM, even with the rotating assembly dynamically precision spin-balanced, due to the heavier-than-stock Chevy piston assembly, the connecting rod could stretch and break and/or the crankshaft could break. Therefore, with the rotating assembly precision and dynamically spin-balanced, it's best to limit the RPM at 4,000 and no higher. Anyway, the correct parts to use are: A 12 (or 13) fin K341 or M16 Kohler engine block for the 38.3 or 40 CID engine, or a 13 fin K341 block for the 40.8 CID engine. To build a 36.7 CID engine, use an aftermarket OEM Kohler-replicated K341 or K361 .040" oversize (3.790") piston, rings and wrist pin. To build a 38.3 CID engine, use a Chevy V8 307 STD size (3.875") OEM-type piston, rings and wrist pin. To build a 40 CID pulling engine, use a Chevy V8 307 .060" oversize (3.9375") OEM-type piston, rings and wrist pin. To build a 40.8 CID engine, use a Chevy V8 327 STD size (4.000") OEM-type piston, rings and wrist pin. Use an OEM Kohler K341 or M16 "new style" (thicker beam) connecting rod. Kohler's "new style" rod has a thicker beam section than previous Kohler rods, which makes it just as durable as a machined billet rod. The rod must be bored with bearing inserts installed, and the flywheel and/or crankshaft must be dynamically and precision spin-balanced. Use a K321, M14, K341, M16 or K361 stock stroke crankshaft. These cranks require less ballast weight for balancing, than using a K301 or M12 crankshaft, which would require A LOT MORE ballast weight for balancing. The K341 or M16 engines have a STD bore of 3.750". But with the Chevy V8 307 STD size (3.875") piston, the Kohler block will have an 1/8" overbore. With the Chevy V8 307 .060" oversize (3.9375") piston, it'll have a 3/16" overbore. And with the Chevy V8 327 STD size (4.000") piston, it'll have a 1/4" overbore. The 307 and 327 piston, rings and wrist pin are available at most auto parts supply stores. Coincidentally, the Chevy 307 and 327 engines have the same stroke as the Kohler K301, M12, K321, M14, K341, M16 and K361 engines, which is 3.250". The K341 or M16 engines with a STD size 3-3/4" Kohler piston, stock 3.250" stroke crankshaft and stock head, they have a compression ratio of 7.4:1. But with a STD size 3-7/8" 307 piston, a stock stroke crankshaft and stock head, the compression ratio will be 7.7:1. And with a STD size 4" 327 piston, a stock stroke crankshaft and stock head, the compression ratio will be 8:1. If the 38.3 CID engine is built to the max at 4,000 RPM with a quality valve job, enlarged intake and exhaust runners, a quality performance torque cam and a bored-out and reworked 1.2" carburetor, it'll produce about 28hp and 37 ft. lb. of torque at 4,000 RPM. And if the 40.8 CID engine is built to the max at 4,000 RPM with a quality valve job, enlarged intake and exhaust runners, a quality performance torque cam and a bored-out and reworked 1.2" carburetor, it'll produce about 30hp and 39 ft. lb. of torque at 3,500 RPM. Here's how to make it happen: According to which Chevy piston is used, the cylinder will need to be bored to either 3.875" (307) or 4.000" (327). The 13 fin block has a thicker cylinder wall. It's more suitable for the 4" piston. Either piston will leave the cylinder wall thinner - more prone to separation or breakage, especially if used in a 12 fin 16hp block or the 18hp OHV block. Therefore, a cylinder restraint strap is highly recommended. Fill in the valve reliefs in the Chevy pistons with aluminum welding to slightly raise the compression, then grind or machine the weld flush with the top of the piston. Leave the notch untouched. (The notch faces the flywheel end of the engine.) For more accurate engine balance, reduced vibration and longevity, the Chevy piston and wrist pin will need to be lightened (reduced in weight) to closely match the weight of an OEM Kohler piston. A groove will need to be ground or machined at each end of the wrist pin hole in either piston for a 15/16" or 24mm internal snap ring to retain the floating wrist pin. The wrist pin in either Chevy piston will need to be ground narrower (shorter) to clear the snap rings when installed. The Kohler K341 and K361 pistons have a compression height of 1.7", and the OEM-type cast Chevy 307 and 327 pistons have a compression height of 1.655", resulting in a negative .045" difference. Therefore... For the top of either Chevy piston to come flush with the top of the block at TDC, the big hole in a (preferably new style/thicker beam) Kohler connecting rod will need to be bored .045" offset toward-> the oil dipper, and bearing inserts will need to be installed. For the top of either Chevy piston to pop out of the cylinder .020" at TDC, bore the big hole in the Kohler rod .065" offset toward-> the oil dipper, and install bearing inserts. Due to the .060" skirt to skirt offset wrist pin (this reduces side thrust friction against the cylinder wall), install either Chevy piston with the notch facing the flywheel end of the engine. (Just like for the K341/K361 Kohler pistons.) Being a heavier piston and rings assembly will be used, the crankshaft must be precision spin-balanced, or the engine will vibrate severely and possibly self-destruct. This means that weight will need to be added to the counterweights on the crankshaft so the engine will run with less vibration. The outsides of the rod journal on the crank may need to be ground away too, to obtain proper balance. For more accurate engine balance, reduced vibration and longevity, the Chevy piston and wrist pin will need to be lightened (reduced in weight) to closely match the weight of an OEM Kohler piston and wrist pin. Click or tap here to learn how to statically balance an engine. Set the ignition timing as usual, at 20º BTDC. If building this type of engine for competition pulling, check your association/club sanctioning rules and requirements so it will be legal within its class!

How to Build a 30 Cubic Inch (NQS Outlaw) Pulling Engine - To build a competitive 30 cubic inch pulling engine, acquire a later model K301 or M12 Kohler block with a large intake port, have the cylinder bored to .050" oversize for a 3.425" aftermarket (J&E or Arias) piston/rings assembly, and use a stock stroke (3.250") crankshaft. This bore and stroke combination calculates to 29.94 c.i. (Install a 1.8" offset intake valve and a 1.5" offset exhaust valve, big steel cam, billet head, and use a 44mm Mikuni carburetor with about an 8" length extension.) The piston and rod combination to use for this particular bore and stroke are as follows: Piston compression height of .875", with an aftermarket billet connecting rod of 6.125" length will bring the piston flush with the top of the engine block. No rods are available for a piston pop out with this particular piston. Piston compression height of 1", with an aftermarket billet connecting rod of 6.000" length will bring the piston flush with the top of the engine block. For a .062" pop out, use a 6.062" rod. For a .125" pop out, use a 6.125" rod. Piston compression height of 1.125", with an aftermarket billet connecting rod of 5.875" length will bring the piston flush with the top of the engine block. For a .062" piston pop out, use a 5.937" rod. For a .125" pop out, use a 6.000" rod. When using a billet connecting rod, being all of these rods have a short oil dipper, it's best to use a flat bottom oil pan for sufficient oiling of the internal parts inside the engine if or when the oil level gets low. But to build a truly competitive 30 c.i. pulling engine, use a 10hp/K241 Kohler block with K301 embossed on the PTO end, for strength and durability, like the one in the photo above È.) To build a stroker 30 c.i. engine, the cylinder will need to be bored to 3.300" and a steel crankshaft with a 3.500" stroke will need to be used. This combination of bore and stroke will calculate to 29.94 cubic inches. (Install an offset 1.8" intake valve and a [centered] 1.5" exhaust valve, .530" lift steel cam, billet head, and use a 44mm Mikuni carburetor with about an 8" length extension.) The piston and rod combination to use for this particular bore and stroke are as follows: Piston compression height of .875" with an aftermarket billet connecting rod of 6" length will bring the piston flush with the top of the engine block. For a .062" piston pop out, use a 6.062" rod. For a .125" pop out, use a 6.125" rod. Piston compression height of 1" with an aftermarket billet connecting rod of 5.875" length will bring the piston flush with the top of the engine block. For a .062" pop out, use a 5.937" rod. For a .125" pop out, use a 6" rod. Piston compression height of 1.125" with an aftermarket billet connecting rod of 5.750" length will bring the piston flush with the top of the engine block. For a .062" pop out, use a 5.812" rod. For a .125" pop out, use a 5.875" rod. When using a billet connecting rod, being all of these rods have a short oil dipper, it's best to use a flat bottom oil pan for sufficient oiling of the internal parts inside the engine if or when the oil level gets low. The longer stroke works better for more torque at high RPM. Due to the small bore and long stroke, this combination produces more torque (lugging power) at open RPM than building a K301 or M12 engine with a .050" overbore and stock stroke (3.250") crankshaft. If the engine is built correctly, and if the correct camshaft and gearing is used, it'll give the competition a kick in their butt! No joke. Use the same size valves, cylinder head and carburetor as the stock stroke engine above È. This bore and stroke combination is legal in the NQS's rules, as long as the cubic inch displacement does not exceed 30. With the 3.300" bore and 3.500" stroke, the cubic inches will be 29.94. But to be closer to 30 cubic inches, have a STD size crank journal ground .015" offset, resulting in a .030" undersize journal, lengthening the stroke to 3.5075". The results with the 3.300" bore and a 3.5075" stroke, the cubic inches will be 29.999, which is slightly under the legal limit. Doing this will gain an edge over the competition. Click or tap here for an explanation of why a longer stroke works better.

Gain More Power and Torque by Moving the [16hp] Piston Closer to the Valves!

Only the OEM 16hp (K341) and 18hp OHV (K361) Kohler engine blocks, the center of the cylinder bore is offset .250" (1/4") with the centerline of the crankshaft main radial ball bearings. Because of the much larger bore, the piston is moved further away from the valves. On OEM pistons, the wrist pin is also located off-center .010" so they'll be less thrust (friction) on the cylinder wall, and this will allow the connecting rod to operate correctly. That's why these particular pistons have a notch in them indicating that the notch must face toward the flywheel.

In a high performance 16hp engine, if the cylinder is bored in its original location (when the piston is installed off-center), and at open RPM, this will create a lot of friction in the area of the cylinder wall that's closest to the valves. To minimize or reduce this power-wasting friction, have the cylinder bored inline or centered with the center of the main radial ball bearings, or closest to the center of the main radial ball bearings as possible, depending on the diameter of the piston to be installed. More compression will be produced by doing this, too.

The best way to do this is acquire a [13 fin] 16hp block with an unworn, standard size cylinder. The reason it's best to use an unworn, standard size cylinder is for example, if a 3.825" (.075" oversized) diameter piston is going to be used, the cylinder will need to be bored .030" closer to the valves. The piston will then travel .030" closer with the main radial ball bearings. The piston still wouldn't be centered, but it'll be closer than the 1/4" offset. Larger diameter pistons may not be moved this close to the valves though. But it will help greatly in the performance characteristics.

All Kohler K-series and Magnum models K241, M10, K301, M12, K321 and M14 engine blocks have 13 cooling fins. Otherwise, there's really nothing else special about these blocks. Except for certain K-series K241 blocks that have K301 embossed on the PTO end, which have a thicker cylinder wall. These blocks works best for the 30 cubic inch class pulling tractors with a stroker engine.

Differences Between the 12 fin and 13 fin 16hp OEM Kohler blocks, and the (Kohler-Replicated 16hp) Aftermarket Blocks -

• The 12 fin 16hp Kohler K-series K341 and Magnum M16 engine blocks have a curved indentation in the cooling fins (clearance for a straight oil fill/dipstick tube) and a threaded hole at the bottom of the cylinder. Count the number of fins from the PTO end of the block. These blocks have a thinner cylinder wall than the 13 fin block. These blocks are most commonly used for light duty lawn and garden equipment applications, and when used for a competition pulling application, can be safely bored up to a 3.937" piston without danger of seriously weakening the support of the cylinder wall. A cylinder restraint strap is highly recommended, especially when burning methanol fuel.
• But the 13 fin 16hp Kohler K341 K-series engine block have a thicker cylinder wall. Count the number of fins from the PTO end of the block. This block is somewhat rare, and used mainly for heavy duty industrial applications, and when used for a competition pulling application, can be safely bored up to a 4.000" piston without danger of seriously weakening the support of the cylinder wall. A cylinder restraint strap is highly recommended too, especially when burning methanol fuel. Both the 12 fin and 13 fin blocks originally have a STD cylinder bore of 3.750".
• If a bigger piston is needed to be used than mentioned above, it's advised to use an aftermarket block, such as Eburg, J2 or Jones. All of these blocks are made of high quality material, and one is not better than the other (quoted by Donnie Sample, of Lakota Racing). These blocks have a much thicker cylinder wall than a 13 fin block and can be safely bored for up to a 4.500" piston. And JE high quality aftermarket high performance pistons, billet connecting rods, etc., can be purchased from Lakota Racing (http://www.lakotaracing.com). When using a billet connecting rod, being all of these rods have a short oil dipper, it's best to use a flat bottom oil pan for sufficient oiling of the internal parts inside the engine if or when the oil level gets low.

Here's something to think about: Between the factory-stock K301, M12, K321 and M14 engines, there's 2.19 cubic inches of difference. This means you get 2 more horsepower for that much difference. But between the stock 14hp and 16hp engines, there's a whopping 4.63 cubic inches of difference, for just 2 more horsepower! The reason for this is because the friction that the piston place against the cylinder wall in the 16hp robs the engine of valuable power. Kohler had to add more cubic inches just to get a maximum of 16hp out of their K341 engine at 3,600 RPM.

And if you're wondering, the cylinder bore is centered in all the [Jones, Julian, etc.] aftermarket blocks.

Do not attempt doing the above È on the K241, M10, K301, M12, K321 or M14 engines! The cylinder on these engines are bored centered with the centerline of the main radial ball bearings. Which should remain this way even for a pulling engine.

Is it worth it moving the piston in a 16hp Kohler?

Engines that use a piston or pistons with a notch have an offset wrist pin. The factory had to do this on a lot of big bore engine blocks because the cylinder bore is offset with the crankshaft main radial ball bearing centerline. To lessen wear on one side of the piston, the offset wrist pin allow the piston to operate straight up and down in the cylinder and not at an angle. If it can be done, then it's definitely worth moving the bore closer to the centerline of the main radial ball bearings. The aftermarket Stock-Altered block has the bore in the stock location (.250" off of the centerline of the crank, toward the starter side of the engine) and is not centered like some must think. Most all the NQS S/A have the bores shifted closer to the valves. By doing this you end up with a tighter combustion chamber for more compression and power. We've done it for a long time on the stock Kohler blocks by offset boring the engine toward the valves, then pressing in a sleeve and offset boring the sleeve for proper fit of the piston and rings. You have to leave about .100 to .125 wall thickness on the sleeve on the valve side to maintain the strength. Depending on how far you move it, the sleeve will show between the fins between the valve box and jug. However, its cheaper just to buy the S/A block and offset bore that, the unfinished bore of a S/A block is only about 3-1/2" so you can offset it quite a bit and still get the bore to cleanup. I paid around $1,000 to sleeve and offset bore an original Kohler block, but it can be done. As far aftermarket blocks that have the bores center over the crank is the Pro/Super Stock blocks like the J2 and others. - This information was provided by my friend, Julian Stahl of Midwest Super Cub.

Why a Longer-Than-Stock Stroke Works Better For More Lugging Power and/or Competition Pulling -

Many people (pullers) believe that an engine will produce more noticeable power (speed) and torque (lugging power) simply by boring the cylinder and installing a maximum of .030" oversize piston and rings assembly. There's no need for this and it will not help the engine to produce anymore noticeable power. The cylinder should be bored oversize only if it's worn beyond specifications or scored. Or if the cylinder is max'd out at .030" and became worn, it can be either be bored for an aftermarket .040" oversize piston and rings assembly. This size piston and rings is available only for the K301, M12, K321, M14, K341, M16 and K361 [OHV] engines. Or the cylinder can be sleeved for a STD for a size piston and rings assembly. See my list of available STD size, .010", .020", .030" and .040" oversize piston and rings further down in this web site. Ê

An engine with a small bore and long stroke works best for more engine torque because at very open RPM, in an engine with a small bore and long stroke, it takes less time for the flame front (combustion pressure) to travel down in the cylinder than it would to travel across the top of the piston in an engine with a large piston and short stroke. Therefore, due to the longer stroke, the fuel burns more thoroughly and the engine produces more torque (lugging power) from the expanding gases of the burning fuel. For competition pulling, with a short stroke engine, at very open RPM, and when the engine is under a load, some of the fuel will go unburned and out the exhaust, and the engine will lack full power. Race car engines and tractor pulling engines are not built on the same principles. A large bore and short stroke engine works best for lightweight racing applications, but definitely not for pulling heavy loads. Racing engines require horsepower to produce more speed, and pulling engines require torque to produce more lugging power. This applies to all piston-powered engines, despite if it's a gas/alcohol burner, Diesel, 2- or 4-cycle. This is also why some "cheaters" in pulling competition like to run an illegal "stroker engine" in a class that require a stock stroke engine. As a result, on a biting track, when all the legal [stock stroke] tractors have run out of power, the tractor with the stroker engine will keep lugging out the gate or on to victory.

What makes more torque (lugging power) is an engine with a long stroke (longer than the bore size; from the factory) or building an engine so it will have a longer stroke by installing a crankshaft with a longer stroke, shorter connecting rod and piston with a higher compression height. For example: there's a world of difference in torque between the Kohler K241/M10 (10hp engines), and the K301/M12 (12hp engines). Unlike a healthy K241, a K301 or M12 in excellent condition that's in a garden tractor when quickly accelerated or revved up will literally "pull you back in the seat." This is an example of what engine torque does. It has a lot of lugging power. The powerful acceleration is because not only does the 12hp have an 1/8" larger cylinder bore than the 10hp, but it has a much longer crankshaft stroke, 3/8" longer to be exact. Plus, the 12hp engine has a higher compression ratio than the 10hp (when the same type of cylinder head is used). In stock form, the 12hp engine is capable of producing 2 more horsepower than the 10hp because of three things: 1) 1/8" larger bore, 2) 3/8" longer stroke, and 3) higher compression ratio. But there's not really that much of a noticeable difference in power and torque between the 12hp and a K321 (14hp) engine, because the 14hp has an 1/8" larger bore, but it has the same length stroke as the 12hp. 14hp engines are able to produce 2 more horsepower than the 12hp because of two things: 1) 1/8" larger bore, and 2) higher compression ratio because they use the same cylinder head with the same size combustion chamber as the 12hp (and 10hp). Another example is the Kohler K141 (6.6hp, K161 (7hp) and K181/M8 (8hp) engines. Besides the smaller bore on the early K141 and K161 engines, these are virtually identical in every way except for the length of the stroke. The K141 and K161 have a crankshaft stroke of 2.500", and the 8hp's crankshaft stroke is 2.750". A 1/4" longer stroke (and higher compression due to the same cylinder head) results in 1hp more. The Kohler opposed twin cylinder engine, KT17 (first design), KT17 Series II, MV16, M18 and MV18 (which are basically made identical) have a crankshaft stroke of 2.750", and the KT19 (first design), KT19 Series II, KT21, M20 and MV20 (which are also basically made identical) engine's crankshaft stroke is 3.063", resulting in about .313" (5/16" or 8mm) difference. The longer stroke is basically the main difference between these engine models. The 5/16" difference in stroke give the bigger engines (KT19/M20/MV20) 2 more horsepower. Many new automotive engines in heavier vehicles nowadays (mainly trucks) have a small cylinder bore and long crankshaft stroke. (Remember Ford's "Power Stroke" truck engine? And GM's LS engines? Simply because these work better for hauling heavy loads at higher RPM.) Return to previous paragraph È

If your association/club sanctioning engine rules and requirements allow a longer-than-stock stroke in any particular class, lengthen or increase the crankshaft's stroke slightly by grinding the crank journal .030" undersize with a .015" offset. Doing this will increase the stroke by .015". This would have to be done on an standard size, unworn journal. If the journal is worn, the amount of wear will have to be subtracted from the increase in stroke. Grinding the journal offset to increase the stroke is a way to slightly increase engine performance. It won't make a world of difference in engine performance, but it does help. Many professional high performance engine builders do this to gain three things:

• Increase the cubic inches to the max in accordance with the rules and requirements for more power and torque.
• Pop the piston out of the cylinder to increase the compression ratio.
• The smaller diameter journal will reduce friction at very high RPM. It'll allow an engine to turn freer, which will help to produce more power and torque.

Here's another thing to consider: half of the .015" increase in stroke is .0075". So .0075" plus the .020" offset rod adds up to .0275". Therefore, the piston will pop out of the cylinder at .0275". If the head was milled at .050", the clearance between the piston and head would be .0225". (.0275" - .050" = .0225".) This would still be a safe margin of clearance. The slightly longer stroke (Click or tap here for an explanation of why a longer stroke works better.) would help to increase the power and torque, PLUS the increase of the compression ratio with the .050" milling of the head (remove the raised ridge that mates with the head gasket) would help in power and torque, too.

Also, a K241 and M10 block can be bored to use a K301 or M12 piston and a K301 and M12 block be bored to use a K321 or M14 piston, but this makes the cylinder wall very thin (approximately 1/8" thick). And it's safe to bore a K301 10hp block for use with a K301 or M12 piston. If an ordinary block is not going to be used for pulling, it should be OK. But if it is going to be used for pulling, It is highly recommended that a cylinder restraint strap (which is sometimes called a "head restraint") be installed (cylinder securely "fastened"-the crankcase) to prevent the possibility of cylinder/crankcase separation, which can be a terrible experience. Also, to maintain precision engine balance, a 14hp crankshaft must be used with the 14hp piston.

If methanol is going to be burned in an engine, and because the engine will have a thinner cylinder wall with increased compression, It is highly recommended that the cylinder be fastened to the crankcase, to prevent the possibility of cylinder/crankcase separation (engine explosion).

The only thing that retains the cylinder to the crankcase is the cylinder wall. If the cylinder is bored for an excessively large piston, this will make the cylinder wall extremely thin. Therefore, the purpose of the cylinder restraint strap (which is sometimes called a "head restraint"), is to prevent the CYLINDER WALL from separating from the CRANKCASE, which will result in a sudden (and possibly terrifying) engine explosion on a cool or cold day. The thicker the cylinder wall, the less chance the cylinder will separate from the crankcase.

When burning methanol fuel, with a thin cylinder wall, and if the cylinder isn't securely fastened to the crankcase, the engine will likely explode at wide open throttle while under a load on a cool night. The reason this will happen on a cool night is, because air is more dense when it's cool, making it "thicker". The colder air is, the "thicker" it becomes. (This is why it's easier to breathe on a cool day than on a hot day, or when in an air conditioned place.) Anyway, in a cool, dense-air environment, an engine, when run at wide open throttle, especially with a big cam, big ports and bigger valves, will build up more compression, placing a tremendous strain on the thin cylinder wall every time combustion occurs.

Furthermore, if you had a K241 or M10 block bored for a K301 or M12 piston, or a K301 or M12 block bored for a K321 or M14 piston, and you use your tractor to push snow, definitely securely fasten or strap the cylinder to the crankcase! Because it now has a much thinner cylinder wall, and the cold winter air is more dense (like the air is thicker or there's more of it). Dense air will build up the compression pressure within the combustion chamber, causing the engine to produce more power. But what also happens is at full throttle, this high compression is pushing upward on the cylinder head, and pulling upward on the cylinder wall. And sometimes the cylinder wall will break, ruining the whole engine. We know, we've had this happen before. No joke. Actually, it's in the foreseeable knowledge of the laws of physics on how a successful pulling engine (and entire tractor) is built. Plus, it's the combination of tractor and driver working together as one that does well at the pulls.

If a bigger flathead engine still won't give you enough power, then use an overhead valve (OHV) engine. These run circles around a flathead of the same cubic displacement, and they produce more horsepower and torque per cubic inch than any flathead engine ever will.

The Cylinder Restraint Strap (Also Called a "Head Restraint") -

On a single cylinder competition Kohler pulling engine that pulls at wide open throttle, when the cylinder is bored oversize with an extremely large diameter piston, this will leave the cylinder wall very thin. So thin in fact, under high compression, the cylinder could break free from the crankcase, especially when burning methanol fuel on a cool night. This have also been known to happen with competition pulling engines burning gas, too. This usually happens on a cool night when the air is dense.

Therefore, to prevent this from happening (especially to a high-dollar engine), it's best to fabricate and install a sturdy cylinder restraint. Restraining the cylinder is when a strap, made of heavy gauge square steel or thick flat aluminum, is placed across the cylinder head and clamped tightly by means of two minimum 1/2" diameter heat-treated and hardened steel threaded rods (All Thread) securely welded to two flat 1/8" thickness x 1" wide T-shaped steel braces that's fastened on the PTO end of the crankcase and against the OEM Kohler bearing plate. Do not use anything smaller than 1/2" diameter threaded rods! Because smaller threaded rods, even if they are heat-treated and hardened, could break, along with the cylinder. (I've personally seen this happen several times to good pulling engines.) Anyway, one brace will need to be fastened against the bearing plate using the two upper bolts just behind the flywheel with longer, grade 8 bolts, and the other brace will be fastened to the PTO end of the crankcase with grade 8 bolts. If there are no two (minimum 3/8") threaded bolt holes present toward the upper part of the PTO end of the block, then they will need to be drilled and tapped to fasten the brace. Position the braces and threaded rods so the strap is in the middle of the cylinder head, next to the spark plug. Only one well-constructed sturdy restraint/strap is sufficient. There's no need to install two restraints/straps across the head.

Furthermore, NEVER install long threaded rods for the restraint system in the top edge of the OEM bearing plate! I've seen where some engine builders do this, and sometimes the [cast] aluminum will break, allowing the cylinder to separate from the crankcase with catastrophic results, as shown in the photo above. Therefore, it's much stronger and less machine work to use two 3/16" x 1" flat pieces of steel welded-together to create an upside-down "T". Remove the flywheel, and fasten one "T" brace using the two upper bolts on the bearing plate. The brace should clear the raised ridges on the OEM large bearing plate (for the gear starter motor). With a small bearing plate however, the ridges will need to be ground away for clearance of the brace. And there's no need to install long threaded rods directly into the crankcase to fasten the cylinder restraint to the crankcase. The other "T" brace can be fastened on the PTO end of the block with a couple of 3/8" grade 8 bolts. If there's no bolt holes for mounting of the brace, two 3/8" threaded holes will need to be drilled and tapped. Measure accurately, cut off, and align the threaded rods, and then securely weld them to the "T' braces. See the photo below. Torque the restraining nuts to 10 ft. lb. each. So strap it now, or scrap it later! Return To Previous Paragraph

Also, due to the extreme pressure a high torque gear reduction starter places on the side of the block of a high compression competition pulling engine to crank it over, it'll be a good idea to fabricate and install a support reinforcement brace as shown in the photo to the right to prevent the possibility of block breakage, especially if a Kohler block have been repaired with welding as the result of a broken connecting rod. Again, brace it now, or possibly scrap it later!

And a K301 or M12 block definitely can't be bored for use with a K341 or M16 piston because the outside diameter of the cylinder wall is too small. And it's doubtful that a K321 or M14 block can be bored for use with a K341 or M16 piston. However, some people have done this with success. In order to make this happen, being the 16hp piston is offset in the cylinder, the center of the outer part of the cylinder will need to be offset one way or the other (not like in the 16hp block) to center the bore in the block as not to break through the cylinder wall during the boring process. Boring a 14hp engine to accept a STD size 16hp piston is a tricky process. First, you must find the "center" of the cylinder. This is done by measuring the outside of the cylinder to find the thinnest and thickest parts. If this isn't done, then the boring process could break through the thin part of the cylinder wall. And if the cylinder is bored offset, the wrist pin in the piston will allow the piston to be centered with the crank journal. If attempting a 16hp piston is installed in a 14hp block, it'll be a good idea to fasten the cylinder to the crankcase rather it's for competition pulling or general lawn and garden use.

The Correct and Professional Way to Sleeve a Cylinder:

FYI: The term "resleeving" is removing a previously installed worn sleeve and installing a new one. And "sleeving" is installing a new sleeve when one wasn't already installed.

A sleeve should be installed in a block if the cylinder wall...

• Is severely gouged or scored and will not "clean up" at .030" or .040" (above ring travel).
• Is bored to maximum of .030" or .040" and is worn beyond specifications or scored, but no bigger piston and rings are available.
• Is cracked towards bottom. (Block is useless if crack is at top of cylinder.)
• Has a wide chunk broke out on the bottom (due to connecting rod failure) and may not provide stability of the piston.

If a block has a small missing chunk at the bottom, and if the chunk isn't wide enough for the piston to be unstable in the cylinder, then don't worry about sleeving the block. If the cylinder wall don't need to be bored (honed) to the next oversize, just use it as it is. As a matter of fact, pulling engines with a machined billet rod require that the lower end of the cylinder be ground away on each side for clearance of the wider rod. If performed correctly, this will not interfere with the stability of the piston whatsoever. But if it's a pretty wide missing chunk, and you have doubts about the stability of the piston, then perhaps the block needs to be sleeved. Before installing the sleeve, the cylinder is made bigger with a boring bar. If performed correctly, the boring bar is adjusted so it won't cut away approximately 1/8" bottom portion of the cylinder. The missing chunk will not interfere with the boring process either. The boring bar machine is positioned firmly with the cylinder to prevent any slippage. As it bores the cylinder, it'll skip over the missing chunk and continue to bore the rest of the cylinder. Then after the sleeve is installed, it's honed for fitting of the piston and rings.

How to Install a Cylinder Sleeve:

1. Acquire a cast iron sleeve that's slightly larger in diameter than the cylinder if a .030" or .040" oversized piston (OEM Kohler-replicated) were installed. Make sure it's slightly longer than the overall length of the cylinder, too. (Virtually any place that sells internal engine parts (pistons, rings, bearings, etc.) offers cylinder sleeves, too.)
2. Bore the cylinder exactly .003" smaller than the outside diameter of the sleeve. Despite the diameter of the cylinder, the .003" interference fit makes for a perfect press fit. Do not make it any tighter or the cylinder could split or crack!
3. When boring the cylinder, leave approximately an 1/8" ledge or "step" at the bottom of the cylinder for the sleeve to butt against and not [possibly] work it's way down into the crankcase as the engine reaches its normal operating temperature.
4. Chamfer or bevel the outside lower end of the sleeve for easier installation in the cylinder.
5. Apply high strength sleeve retainer around the sleeve or in the cylinder, and using an upright hydraulic press, carefully and slowly press the sleeve perpendicular into the cylinder until it bottoms out against the ledge. To ease installation of the sleeve into the cylinder, heat the engine block in an oven and cool the sleeve in a freezer. It should then just slip in without using a press. But this must be done quickly before the block cools and sleeve warms up.
6. Once the sleeve is installed, grind or machine the protruding upper portion of the sleeve so it's even with the top of the engine block.
7. Bore or hone the sleeve for a standard size piston and rings assembly, then chamfer the upper edge of the sleeve so the rings will slide in easy upon installation.
8. That's it! Any professional machine shop that performs quality machine work on automotive engines should be able to install a sleeve in a Kohler or virtually any other engine block. Watch this YouTube video to learn more: How Do We SAVE A 289 Ford That Sat In A JUNK YARD For OVER 40 years?

Maintain Proper Crankcase Vacuum and Ventilation so the Engine Will Produce More Power and Prevent Loss of Oil Through the Breather Assembly!

The reed valve or umbrella check valve are a very important part of the crankcase breather assembly on a small engine. These allow the escape of excess air pressure inside the crankcase, prevents the loss of oil through the crankcase breather assembly (as long as the engine isn't over-revved or the piston rings are in good condition), prevents outside dust and dirt from entering the crankcase, and they maintain vacuum within the crankcase and proper ventilation so the engine will produce more power and last longer. It works exactly the same as the positive crankcase ventilation (PCV) valve as the emission control in an automotive engine crankcase ventilation system since 1960.

When reinstalling the reed valve/breather plate assembly on models K141, K160/K161, L160/L161, L181, K181 and M8, the reed valve faces outward. If the reed valve on the breather plate is installed in reverse and toward the crankcase, the engine will blow excessive amount of oil out the breather assembly. And on all Kohler engine models, the small hole in the reed plate faces downward so any oil that accumulates in the breather assembly will drain back down into the crankcase. Also, if using clear RTV silicone adhesive sealant, be careful not to block or plug the oil drain hole with the sealant when reinstalling the breather plate and breather cover to the crankcase. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.

If wishing to use a rubber hose to route the oil vapors down and away from the engine and tractor (for cleanliness), the louvered vent openings on the OEM Kohler crankcase breather cover can be hammered closed, then a 7/16" hole will need to be drilled and tapped towards the upper left corner of the cover for a 1/4" NPT (preferably brass, for appearance reasons) elbow fitting. The reason the hole should be towards the upper left corner is so the fitting won't interfere with the carburetor when it is mounted directly to the engine block without an extension, such as on a Stock, Hot Stock or Stock-Altered pulling engine. To prevent loss of oil, do not install the cover upside-down!

The "filter" in the crankcase breather assembly is actually an oil trap. It traps and suspends oil vapors from exiting the crankcase at higher RPM, then allows the oil to drain back down into the crankcase when the engine is at an idle or turned off. It's too coarse to be a filter of any kind. It's a must for a high RPM pulling engine.

When reinstalling the crankcase breather assembly on a single cylinder engine, make sure all the original components are reinstalled in the same order they were removed so that proper crankcase vacuum is maintained. This is important on any engine, especially a pulling engine. More horsepower will be created and the inside of the crankcase will stay clean longer.

Dyno tests have proven that a single cylinder engine will produce more power with the reed valve and breather plate installed. Some pullers like to use just a fabricated aluminum cover (an "aluminum valve cover" just for looks) and not the reed valve and breather plate. This is wrong because without the reed valve in the crankcase breather, with the engine running and as the piston(s) moves upward, (in a single- or two-cylinder engine) air (and dust fragments in the atmosphere) will be drawn into the crankcase through the breather cover hole. And as the piston goes back down, air will be forced out of the crankcase through the same hole. This rapid "in and out" movement of air will rob an engine of power because air must be compressed through the small breather hole. Hot air (and the hot oil vapors) are supposed to be forced out of an engine, not sucked in. And the piston will automatically vent the pressure on the downward stroke through the breather hole.

When to Use a Crankcase Vacuum Pump in a High Performance/High RPM Engine -

A crankcase vacuum pump is a belt-driven or electrically-operated motorized pump to draw air out of the crankcase to create a vacuum, or maintain negative air pressure. A 12 volt high volume electric fuel pump can also be used as a crankcase vacuum pump with the inlet port connected to the crankcase breather and the outlet port empty into the atmosphere. Anyway, high performance and high RPM single cylinder pulling engines don't require a crankcase vacuum pump because the backside or underneath of the piston force air out of the crankcase on it's downward stroke, and the reed valve in the crankcase breather assembly prevents air from reentering the crankcase. But high performance and high RPM multi-cylinder engines will benefit greatly from a crankcase valve pump. With multi-cylinder engines, one or several pistons is on the downward stroke while the other piston(s) is on the upward stroke. With this configuration, no air can be forced out of the crankcase. Heat from normal engine operation cause the crankcase oil to build up pressure, and this is what relieves the pressured [hot] air from the crankcase. This is why two-cylinder small engines have a reed valve in the crankcase breather assembly, and automotive engines crankcase is vented through the valve covers. A crankcase vacuum pump will draw out all the [hot] air from the crankcase to maintain a vacuum, or negative crankcase pressure. With no air in the crankcase for the backside of the pistons to push against, a multi-cylinder engine will produce more power and torque at higher RPM.

On the cast iron block 7hp and 8hp Kohler engines, the reed plate is installed with the reed valve facing outward or towards you. This allow air to escape out the crankcase, but no air can enter into the crankcase.

How the Reed Valve Works:

The underneath or backside of the piston creates a vacuum within the crankcase and valve spring compartment. As the piston travels downward, air that's in the crankcase is forced out through the reed valve and crankcase breather cover hole, and when the piston travels upward, air wants to be drawn or sucked back in (under vacuum), but the reed valve prevents this from happening. Therefore, a vacuum is created and maintained within the crankcase. Air can only be forced out of the crankcase and not be allowed in. By the way - the Kohler reed valve and inner plate can be substituted for an automotive positive crankcase ventilation (PCV) valve. But most pulling tractors running a limited RPM engine really don't need a PCV valve to maintain crankcase vacuum. Nothing will be gained by installing one. It'll just be for looks only. Besides, the reed valve design works excellent just the way the factory intended.

If there's a steady puff of smoke coming out of the crankcase breather, the reason for this is because the piston rings are worn. What is happening is a small part of the exhaust gases in the combustion chamber is bypassing the gaps in the rings, goes down into the crankcase and then out the breather. As the rings wear more, more pressure from the combustion will build up in the crankcase, and some crankcase oil may be forced out the breather hole, especially at higher RPM. When this happens, it's time for a complete engine rebuild. If an engine rebuild is out of the question any time soon, what could be done to prolong the engine life a little longer is switch to 10W40 or 20W50 full synthetic motor oil for warm weather use.

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Crankcase Breather Assembly/Cover Gaskets. Fits Kohler engine models K90/K91. High quality aftermarket. Replaces Kohler part # 220370-S. $1.60 each, plus shipping & handling. OEM Kohler part # 220370-S. $4.85 each, plus shipping & handling. Crankcase Breather Assembly and Cover Gaskets. FYI - The gaskets listed below are interchangeable between the Kohler engine models K141, K160/K161, KV161, L160/L161, L181, K181, M8, MV16, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18, MV18, M20 and MV20. Fits specificity Kohler engine models K141, K160/K161, KV161, L160/L161, L181, K181 and M8. OEM Kohler part # 230048-S. $5.85 each, plus shipping & handling. Fits specificity Kohler engine models MV16, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18, MV18, M20 and MV20. OEM Kohler part # 52 055 01-S. $5.75 each, plus shipping & handling. Crankcase Breather Reed Plate Inner Gaskets. Fits Kohler engine models K241, M10, K301, M12, K330/K331, K321, M14, K341, M16 and K361. High quality aftermarket. Replaces Kohler part # 235048-S. $1.00 each, plus shipping & handling. OEM Kohler part #'s 235048-S. $4.80 per two gaskets, plus shipping & handling. Crankcase Breather Cover Outer Gaskets. Fits Kohler engine models K241, M10, K301, M12, K330/K331, K321, M14, K341, M16 and K361. High quality aftermarket. Replaces Kohler part # 275144-S. $2.00 each, plus shipping & handling. OEM Kohler part #'s 275144-S. $5.40 each, plus shipping & handling.
Crankcase Breather and Air Cleaner Neoprene Rubber Seal. Fits Kohler engine models K90/K91, K241, K301, K321, K341, K361, K582, M10, M12, M14, M16, MV16, M18, MV18, M20, MV20, CH640, CH730, CH740, CV670, CV680, CV730 and CV740. Dimensions: 1/4" I.D. x 1/2" O.D. x 9/16" length. FYI - A reinforced rubber fuel hose of the same size can be substituted for this part. OEM Kohler part #'s 220369-S, 231032-S. $5.65 each, plus shipping & handling. Crankcase Breather and Air Cleaner Neoprene Rubber Seal. Fits Kohler engine models K141, K160/K161, L160/L161, L181, K181, M8, MV18 MV20, CH18, CH20, CH22, CH25, CH730 and CV15. Dimensions: 1/4" I.D. x 1/2" O.D. x 7/8" length. FYI - A reinforced rubber fuel hose of the same size can be substituted for this part. OEM Kohler part #'s 230046-S. $4.90 each, plus shipping & handling.
Small Size Crankcase Breather Fibrous Filter (Oil Trap). Fits Kohler engine models K91, K141, K160/K161, KV161, L160/L161, L181, K181, M8, and opposed (flathead) twin cylinder engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18 and M20. (Kohler engine models MV16, MV18 and MV20 requires no part of this kind.) Replace deteriorated and crumbly filter to prevent loss of oil. NOTE: This "filter" is actually an oil trap. It traps and suspends oil droplets and prevents oil vapors from exiting the crankcase at higher RPM, then allows the oil to drain back down into the crankcase when the engine is at idle or turned off. (It's too coarse to be a filter of any kind, but Kohler calls it a filter.) Dimensions: Approximately (±) 1-1/4" x 1-1/4" square. OEM Kohler part only; not included in aftermarket engine gasket set. [Return to previous section] OEM Kohler part # 231419-S. $7.45 each, plus shipping & handling. Medium Size Crankcase Breather Fibrous Filter (Oil Trap). Fits Kohler engine models K241, K301, K330/K331, K321, K341 with the round shaped metal air cleaner/filter assembly, and various Kohler Magnum models M12, M14 and M16. Replace deteriorated and crumbly filter to prevent loss of oil. NOTE: This "filter" is actually an oil trap. It traps and suspends oil droplets and prevents oil vapors from exiting the crankcase at higher RPM, then allows the oil to drain back down into the crankcase when the engine is at idle or turned off. (It's too coarse to be a filter of any kind, but Kohler calls it a filter.) Fills about 1/3 center area of breather plate. To be used with crankcase breather cover with open atmospheric vent and external oil control baffle shield part # 235117-S (listed below). Dimensions: Approximately (±) 1-1/2" wide x 2" tall. OEM Kohler part only; not included in aftermarket engine gasket set. OEM Kohler part # 235118-S. $15.95 each, plus shipping & handling. Large Size Crankcase Breather Fibrous Filter (Oil Trap). Fits Kohler AQS "Quiet Line" engine models K241, K301, K321, K341, K361 with the oblong shaped metal air cleaner/filter assembly, and various Kohler Magnum engine models M10, M12, M14 and M16. Replace deteriorated and crumbly filter to prevent loss of oil. NOTE: This "filter" is actually an oil trap. It traps and suspends oil droplets and prevents oil vapors from exiting the crankcase at higher RPM, then allows the oil to drain back down into the crankcase when the engine is at idle or turned off. (It's too coarse to be a filter of any kind, but Kohler calls it a filter.) Fills entire area of breather plate. To be used with crankcase breather cover with PCV breather vent hose/tube and external oil control baffle shield and reed stop part # 270146-S (listed below). Dimensions: Approximately (±) 3" wide x 2" tall. OEM Kohler part only; not included in aftermarket engine gasket set. OEM Kohler part # 47 050 01-S. $9.85 each, plus shipping & handling. [Return to Previous Section, Paragraph or Website]
Crankcase Breather Reed Valve for Kohler engine model K91. Replace damaged, rusted or broken reed valve to prevent loss of oil through breather vent hole, prevent outside dust and dirt from being drawn into crankcase and maintain crankcase vacuum and proper ventilation so engine will produce more power and last longer. FYI - The only substitute for this part is to adapt a threaded automotive PCV valve on the crankcase breather cover. OEM Kohler part # 220379-S. $5.50 each, plus shipping & handling. Crankcase Breather Plate and Reed Valve Assembly for Kohler engine models K141, K160/K161, L160/L161, L181, K181 and M8. Replace damaged, rusted or broken breather plate/reed valve assembly to prevent loss of oil through breather vent hole, prevent outside dust and dirt from being drawn into crankcase and maintain crankcase vacuum and proper ventilation so engine will produce more power and last longer. FYI - The only substitute for this part is to adapt a threaded automotive PCV valve on the crankcase breather cover. New Old Stock or used and in excellent condition. Discontinued Kohler part # 230066-S. $15.00 each, plus shipping & handling. (When available.) Modified Kohler opposed twin cylinder engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 or MV20 crankcase breather plate and umbrella check valve or reed valve assembly so it will fit Kohler engine models K141, K160/K161, L160/L161, L181, K181 and M8. NOTE: The neoprene rubber seal is not needed with the breather that have the umbrella check valve.Replaces Kohler part # 230066-S. $20.00 each, plus shipping & handling. Crankcase Breather Reed Valve. Fits Kohler engine models K241, M10, K301, M12, K330/K331, K321, M14, K341, M16 and K361. Replace damaged, rusted or broken reed valve to prevent loss of crankcase oil through breather vent hole at higher RPM, prevent outside dust and dirt from being drawn into crankcase, and maintain crankcase vacuum so engine will produce more power. FYI - The only substitute for this part is to adapt a threaded automotive PCV valve on the crankcase breather cover. OEM Kohler part # 235047-S. $33.10 each, plus shipping & handling. Old Style Replacement Neoprene Rubber Umbrella Check Valve and Crankcase Breather Plate w/Umbrella Check Valve used on Kohler KT-series and Magnum opposed twin cylinder engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Replace deteriorated rubber umbrella check valve to prevent loss of oil through breather vent hole, prevent outside dust and dirt from entering crankcase and maintain crankcase vacuum so engine will produce more power. NOTE: The old style breather with the umbrella valve works just as well as the new style breather with the steel reed valve. So if the umbrella valve of your breather is damaged, it can be replaced. Also, it cost less to just replace the umbrella valve than the entire breather plate with the steel reed valve. FYI - The only substitute for this part is to adapt a threaded automotive PCV valve on the crankcase breather cover. New Neoprene Rubber Umbrella Check Valve Only. High quality aftermarket. Dimensions: 1" diameter x 3/16" diameter center plug. Retaining hole in breather plate will need to be drilled-out/enlarged to 3/16". Replaces discontinued Kohler part # 52 462 01. $4.00 each, plus shipping & handling. Old Style Crankcase Breather Plate with New Neoprene Rubber Umbrella Check Valve Installed. Used and in excellent condition. Discontinued Kohler part #'s 52 096 22, 52 096 41 or 52 452 07. $20.00 each, plus shipping & handling. (When available.) New Style Crankcase Breather Plate with Steel Reed Valve for Kohler KT-series and Magnum opposed twin cylinder engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Each listed below replaces OEM Kohler part # 52 254 07. NOTE: The two items listed below are basically the same part with different part numbers and prices. FYI - The only substitute for this part is to adapt a threaded automotive PCV valve on the crankcase breather cover. OEM Kohler part # 52 035 02-S. $37.50 each, plus shipping & handling. OEM Kohler part # 52 035 04-S. $27.10 each, plus shipping & handling.
Inner Crankcase Breather Plate. Fits Kohler engine models K241, M10, K301, M12, K330/K331, K321, M14, K341, M16 and K361. Along with the reed valve installed, this part prevents outside dust and dirt from entering crankcase, and maintains crankcase vacuum and ventilation so engine will produce more power. Has internal oil control baffle splash shield spot-welded on backside of plate. IMPORTANT: Install with oil drain hole facing down. OEM Kohler part # 235631-S. Used and in excellent condition. $10.00 each, plus shipping & handling. (When available.) New. $21.80 each, plus shipping & handling.
External Crankcase Breather Oil Control Baffle Shield. Fits Kohler engine models K241, K301, K330/K331, K321, K341 with the round shaped metal air cleaner/filter assembly, and various Kohler Magnum models M12, M14 and M16 with an open atmospheric vent in crankcase breather cover. Prevents loss of oil through crankcase breather cover vent hole. Positions against reed valve inside of breather plate (listed below Ê). To be used with crankcase breather cover with open atmospheric vent and small crankcase breather fibrous filter (oil trap) part # 235118-S (above È). OEM Kohler part # 235117-S. Used and in excellent condition. $2.00 each, plus shipping & handling. (When available.) New. $4.15 each, plus shipping & handling. Crankcase Breather Oil Control Baffle Shield and Reed Stop. Fits Kohler AQS "Quiet Line" engine models K241, K301, K321, K341, K361 with the oblong shaped metal air cleaner/filter assembly, and various Kohler Magnum engine models M10, M12, M14 and M16. Positions against reed valve inside of breather plate (listed below Ê). To be used with positive crankcase ventilation (PCV) system breather vent hose/tube and large crankcase breather fibrous filter (oil trap) (part # 47 050 01-S; listed above È). OEM Kohler part # 270146-S. Used and in excellent condition. $2.50 each, plus shipping & handling. (When available.) New. $5.20 each, plus shipping & handling.
Crankcase Breather Cover. Fits Kohler engine models K241, M10, K301, M12, K330/K331, K321, M14, K341 and M16 with the round shaped metal air cleaner/filter assembly. Replace bent, damaged or rusted cover to prevent leaking oil. Vent open to atmosphere. Used and in excellent condition. Discontinued Kohler part # A-235418-S. $9.00 each, plus shipping & handling. (When available.)	Crankcase Breather Cover. Fits Kohler AQS "Quiet Line" engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361 with the oblong shaped metal air cleaner/filter assembly. Replace bent, damaged or rusted cover to prevent leaking oil. Vent hole accepts PCV neoprene rubber breather hose/tube(s) listed below. OEM Kohler part # 47 096 01-S. Used and in excellent condition. $10.00 each, plus shipping & handling. (When available.) New. $18.55 each, plus shipping & handling.
Neoprene Rubber Crankcase Breather Vent Hose/Tube. Approximately 4" unextended length. Fits Kohler AQS "Quiet Line" engine model K181 with specification numbers 301000-301058, and Magnum M8 with specification numbers 301500-301656. Replace cracked, dry-rotted or missing breather hose/tube to prevent dirty/dusty outside air from entering combustion chamber, which will cause excessive engine wear. Fastens between base of metal air cleaner/filter assembly and crankcase breather cover. Part of positive crankcase ventilation (PCV) system; vents back-pressure from inside crankcase into air intake to help oil stay clean longer. OEM Kohler part # 41 326 02-S. $19.55 each, plus shipping & handling. Neoprene Rubber Crankcase Breather Vent Hose/Tube. 3-11/32" overall length. Fits various Kohler Magnum engine models M10, M12, M14 and M16. Replace cracked, dry-rotted or missing breather hose/tube to prevent dirty/dusty outside air from entering combustion chamber, which will cause excessive engine wear. Fastens between base of air cleaner/filter assembly and crankcase breather cover. Part of positive crankcase ventilation (PCV) system; vents back-pressure from inside crankcase into air intake to help oil stay clean longer. Used and in excellent condition or New Old Stock. Discontinued Kohler part # 47 326 03-S. $15.00 each, plus shipping & handling. (When available.) Neoprene Rubber Crankcase Breather Vent Hose/Tube. 3-17/32" overall length. Fits Kohler K-series AQS "Quiet Line" engine models K241, K301, K321, K341 and K361. Used on Cub Cadet garden tractor models 800, 1000, 1200, 1250, 1450 and 1650. Replace cracked, dry-rotted or missing breather hose/tube to prevent dirty/dusty outside air from entering combustion chamber, which will cause excessive engine wear. Fastens between base of oblong shaped metal air cleaner/filter assembly and crankcase breather cover. Part of positive crankcase ventilation (PCV) system; vents back-pressure from inside crankcase into air intake to help oil stay clean longer. OEM Kohler part # 47 326 01-S. $17.50 each, plus shipping & handling. Neoprene Rubber Crankcase Breather Vent Hose/Tube. 3-29/32" overall length. Fits various Kohler Magnum engine models M10, M12, M14 and M16. Replace cracked, dry-rotted or missing breather hose/tube to prevent dirty/dusty outside air from entering combustion chamber, which will cause excessive engine wear. Fastens between base of air cleaner/filter assembly and crankcase breather cover. Part of positive crankcase ventilation (PCV) system; vents back-pressure from inside crankcase into air intake to help oil stay clean longer. Used and in excellent condition or New Old Stock. Discontinued Kohler part # 47 326 04-S. $35.00 each, plus shipping & handling. (When available.) Neoprene Rubber Crankcase Breather Vent Hoses/Tubes. Fits various opposed twin cylinder Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18, M20, CV18, CV20, CV22, CV23, CV25, CV620, CV624, CV640, CV670, CV675, CV680, CV724, CV730, CV740, CV745 and CV750, according to specification number. Replace cracked, dry-rotted or missing breather hose/tube to prevent dirty/dusty outside air from entering combustion chamber, which will cause excessive engine wear. Fastens between base of air cleaner/filter assembly and crankcase breather cover. Part of positive crankcase ventilation (PCV) system; vents back-pressure from inside crankcase into air intake to help oil stay clean longer. New Style. Approximately 3-5/8" Unextended Length. OEM Kohler part # 25 326 06-S. $14.10 each, plus shipping & handling. Old Style. Approximately 3-3/8" Unextended Length. OEM Kohler part # 52 326 06-S. $26.50 each, plus shipping & handling. The items listed below can be used to convert Kohler AQS "Quiet Line" engine models K241, K301, K321, K341, K361, or Magnum engine models M10, M12, M14, M16 with the positive crankcase ventilation (PCV) crankcase breather cover to open atmospheric vent. Makes for a nice, distinctive appearance. Use with 1/2" metal hole plug (listed below) in air cleaner base. 1/4" NPT x 3/8" Barb 90º Angle Brass Fitting. Use with metal hole plug listed below. Use 1/4" NPT hand tap to cut threads in cover to accept this fitting. $10.00 each, plus shipping & handling. 1-5/8" unextended length Neoprene Rubber Crankcase Breather Vent Hoses/Tube. Originally designed for Kohler engine models CH18, CH730 and CH740. OEM Kohler part # 24 326 86-S. $5.95 each, plus shipping & handling. 2" unextended length Neoprene Rubber Crankcase Breather Vent Hoses/Tube. Originally designed for Kohler engine models CH18, CH20, CH23, CH640, CH730, CH740, CV18, CV20, CV22, CV23, CV25, CV620 and CV640. OEM Kohler part # 24 326 83-S. $3.45 each, plus shipping & handling. 3-5/8" unextended length Neoprene Rubber Crankcase Breather Vent Hoses/Tube. Originally designed for Kohler engine models 61508, 61532, 61533, 61537, 61540, 61547, 61553, 61554, 61557, 61558, 65508, 65530, 65534, 65538, 65550, 65551, 65552, 65553, 65557, 65582, 65599, 65609, 67508, 67515, 67527, 67529, 67541, 67544, 67552, 69511, 69526, 69537, 72509, 75518, CV620, CV640 and CV640. Also fits certain single cylinder Wisconsin engines. OEM Kohler part # 24 326 87-S. $7.50 each, plus shipping & handling. 1/2" Metal Hole Plug. Use to plug AQS breather vent hole in base of oblong shaped metal air cleaner/filter assembly on Kohler AQS "Quiet Line" engine models K241, K301, K321, K341 and K361, and Magnum engine models M10, M12, M14 and M16. Use with brass fitting or neoprene rubber crankcase breather vent hoses/tubes listed above. Apply clear RTV silicone adhesive sealant for an air-tight seal, and bend locking tangs outward/hammer flat to secure permanently in hole. $2.00 each, plus shipping & handling.
FYI: The governor assembly to crankcase vent breather hoses/tubes (Kohler part #'s 277392-S and X-484-1-S) for Kohler engine models K482, K532 and K582 are no longer available from Kohler. Use a neoprene rubber or vinyl hose or tubing of the appropriate size as a replacement.

Use an Auxiliary Crankcase Breather System to Prevent Oil Spillage at Open RPM [Top of Page]

The factory OEM crankcase breather alone isn't sufficient enough for all high performance single cylinder engines, especially big cubic inch engines running at open RPM. These engines build up more positive pressure within the crankcase due to the longer stroke (Click or tap here for an explanation of why a longer stroke works better.) and bigger piston. The downward movement of the piston will force air out of the crankcase. at open RPM, the small holes in the OEM engine block and breather assembly aren't large enough for a sufficient amount of air to pass through or exit the crankcase. When air exits the crankcase through the OEM breather at open RPM, it will sometimes take some crankcase oil with it, spewing an oily mess on the track, and probably on the tractor. So if an engine has this problem (not all engines spew oil at open RPM, and to keep this from happening, the engine needs an auxiliary crankcase breather setup. The auxiliary crankcase breather setup helps relieve some of the air pressure within the crankcase that's placed against the stock crankcase breather assembly.

By looking at the photo to the right ->, you'll notice that this is an open breather system with no one-way check valve (PCV valve) to prevent air from re-entering the crankcase. This is how it works: the faster a single cylinder engine revs, air has less time to exit and re-enter the crankcase. In other words, at open RPM, being air can be compressed as well as expanded [within a container], it cannot re-enter the crankcase through the auxiliary breather simply because there isn't enough time for it to do so. Therefore, the crankcase maintains zero vacuum within. The auxiliary breather cap also has a filter in it. This is to prevent dust and dirt from entering the crankcase at low RPM. And the auxiliary crankcase breather setup doesn't help to make more horsepower. It just keeps oil inside the engine and off the track.

To install the auxiliary crankcase breather setup on a Kohler K-series or Magnum 10-16hp engine, parts needed are: 3/4" NPT elbow fitting, a short piece of 3/4" NPT pipe (to attach the clear vinyl tubing), 12" of clear vinyl tubing and a MOPAR automotive crankcase breather cap. To install the fitting in the block, the welch plug where the governor gear assembly is located will need to be removed, then a 3/4" NPT tap will need to be used to cut threads in the welch plug hole for the fitting, and the rest of the installation is easy to figure out.

How to Measure the Cylinder(s) in an Engine for Wear -

To accurately measure the cylinder(s) in an engine for taper wear, use an outside micrometer and a precision telescoping T-shaped hole gauge of the appropriate size. These will not measure the depth of scratches or scoring in a cylinder. To check for and visually see any obvious scratches or scoring, first deglaze the cylinder, and then use a bright light or your fingernail to determine if the cylinder needs to be bored oversize (or a sleeve installed). If your fingernail "catches" in the groove(s), then the cylinder definitely needs to be oversized or a sleeve installed.

Checking for a Worn Piston -

If there's any oil on top of the piston, this means the piston is badly worn, which caused the rings, especially the 2nd ring, to wear. New top and middle piston rings have a square edge (actually, the middle ring has a slightly "angled" edge), and they operate in a particular manner. The top ring holds the compression within the combustion chamber. The middle ring is the oil scraper or oil control ring. The "angled edge" allow it to flex as it travels up and down in the cylinder. It slides over the oil on its way up in the cylinder and scrapes the oil on it's way down. As the skirt of the piston wears, the piston wobbles side to side in the cylinder (called piston slap), causing the square or angled edge on the rings to become rounded. When this happens, the middle ring can't slide over the oil or scrape it down as well. Instead, it pushes some of the oil past the gap in the top ring and place it on top of the piston, and the oil gets burned along with the gas. The oil ring assembly is the lubricator. It lubricates the cylinder wall and other rings so they'll last longer. The rings in all 4-cycle engines, rather it be a gas or diesel engine, small engine or automotive, operate the same way. 2-cycle engines only have one or two compression rings on the piston.

Oil on top of the piston indicates that crankcase oil is by-passing the 2nd ring and is being pushed up to the top of the piston. The 2nd ring has a slightly angled square edge, which flexes. It's supposed to slide over the oil on its way up, and scrape the oil on its way down. This is why it's called the oil control ring. The only thing that will cause the 2nd ring not to control the oil is a loose-fitting piston. As the piston rocks in the cylinder, this causes the slightly angled edge to wear away and become rounded, and the ring can no longer control the oil.

Speaking of a worn piston, if an engine makes an uneven "clattering" sound when running or especially when under a load, then perhaps the piston is worn and loose in the cylinder bore. To check for a worn piston, remove the cylinder head, and with the piston positioned at TDC, forcibly and quickly move the piston side to side by hand (side thrust of the crankshaft). If you hear a "slap, slap" sound, then the piston is badly worn.

Also, carbon deposits in a combustion chamber of a flathead engine can "eat away" the edge of the piston that's next to the valves. Carbon is harder than any metal. The only thing that's harder than carbon is diamond. Carbon deposits is what's left behind with the incomplete burning of a fossil fuel. This is why it's so important to keep an engine fine-tuned, so it'll leave behind very little carbon as much as possible.

According to Kohler's specifications, when using an OEM or aftermarket piston in an engine, the piston-to-cylinder wall clearance should be no less than .007" and no more than .010". But make it tighter for pulling (.007"). Because unlike a forged, high performance piston (Arias and J&E), OEM or aftermarket pistons will wear slightly when used in a high RPM or wide open throttle application. As for forged, high performance pistons, when hot, they swell (increase in size) more than an OEM piston. Therefore, requiring slightly more clearance. Most high performance pistons require a .010"-.014" oil clearance. But check with the manufacturer of the piston for the exact clearance.

About Piston Ring End Gaps -

As an engine heats up while running, due to normal combustion heat and heat from cylinder wall friction, the piston rings expand, decreasing the width of the gap in the rings to seal in the compression and better control oil usage. This is normal for all piston-powered engines. The smaller gap specs shown in Kohler's (or any) engine repair manual are for low RPM engines (up to 3,600 RPM) and the wider gap specs are for high performance engines running high RPM or wide open throttle because they operate at a much higher temperature. The gap in all piston rings are NOT machined perfect. It's important to fit each ring squarely in the cylinder with the piston and then use a feeler gauge to accurately measure the gap, especially when building or freshening a high performance engine. Always check the ring end gaps (and piston thrust face) for proper clearance before installing the rings in the cylinder to prevent them from galling or severely gouging the cylinder wall when the engine is hot.

Use a special-made piston ring filer tool to file or grind the ends of each ring until the gap is within specs. Don't file or grind away too much metal! Once metal is removed, it can't be replaced. File or grind the end(s) of the rings just a little at a time, measure the gap with the ring in the cylinder, and if it's not within specs, grind it some more until it is within specs. Typically, the 10-16hp Kohler piston ring end gaps set at .010"-.020". The lesser clearance is for up to 3,600 RPM operation, and the greater clearance is for engines that run at open RPM. The ring gaps closes up due to heat expansion and friction as the engine reaches operating temperature. This applies to all types of piston rings, OEM stock and high performance aftermarket, small engine and automotive engines.

Offset or Stagger the Piston Ring End Gaps -

Being piston rings rotate in the cylinder as the engine heats up and cools down, there is really no need to offset or stagger the ring end gaps anywhere from 120° to 180° on the piston before installation in the cylinder. Actually, it doesn't matter if the ring end gaps are offset with each other or not because heat expansion rotates the rings in the cylinders a few thousandths of an inch each time the engine is ran. Personally, whenever I install new rings in an engine, I always prefer to offset or stagger the ring end gaps 180° just because it makes A-1 Miller's feel good knowing they're offset. But then a few years later when I freshen the same engine (install new rings, etc.), upon removal of the piston, I notice that the end gaps in the rings are almost aligned with each other. It's weird how this happens, heat expansion does it. Piston rings produce no wear pattern on the cylinder wall either. As an engine runs and reaches operating temperature, piston rings rotate a few thousandths of an inch due to heat expansion from friction and they contract (shrink) while the engine cools when it is shut off. This is why some engines make an clicking sound immediately when it's shut off. There is no way to prevent this from happening. The ring gaps close up when the engine reaches operating temperature, too. This applies to all 4-cycle piston-powered water and air-cooled engines, being a small engine, automotive, diesel, airplane, etc. And there's really no need to offset the ring gaps before installing the piston/rings in the cylinder. But if it'll make you feel better, before installing the piston in the cylinder, go ahead and offset or stagger the end gaps anyway.

Use a generous amount of clean SAE 30 weight heavy duty conventional (petroleum-based) motor oil to lubricate and coat the cylinder wall, piston and rings (be sure to coat all other moving parts inside the engine as well with the same oil). Synthetic motor oil shouldn't be used on the piston rings or as a break-in (wear-in) oil because it'll take much longer for the rings and other moving parts to produce a hardened wear surface, especially for the lifters and cam lobes.

NEVER use a lightweight spray lubricant such as Liquid Wrench or WD-40 on internal parts to assemble a fresh engine! Spray lubricants are too thin and will cause premature wear to the bearings, camshaft lobes, piston, rings and possibly the cylinder wall! Liquid Wrench and WD-40 works great for a lot of other things, but not for vital lubrication during the assembly of a rebuilt engine. And on a cast iron block Kohler engine, ALWAYS apply oil or grease inside the camshaft and on the cam pin to prevent [most likely] engine seizure just after starting and running for a few minutes!

For long-term storage of virtually any rebuilt engine or short block to prevent any rust build-up, many knowledgeable and experienced mechanics apply protective rust inhibitor oil spray, white lithium grease spray or automotive chassis grease on the piston rings, cylinder wall(s), rod and main journals, camshaft lobes, camshaft pin, and all other internal engine parts that make contact with each other. This provides a thin film that that seals out moisture, which protects vulnerable internal engine parts so they will not rust due to any condensation that may be present in the air. Because rust is the biggest enemy of internal engine parts. When the engine is first started, the grease will melt, and dissolve and mix with the crankcase oil, which will harm nothing. The reason grease works better than motor oil for long-term storage is because eventually the oil will seep past the ring gaps, and drain off of other internal engine parts, and down into the crankcase, and then all there'll be is a very thin coat of oil, or depending on the length of storage time, any oil at all, to protect the parts upon engine startup, which would likely cause excessive wear to valuable parts. In an engine with an oil pump, grease works better to provide longer lubrication of the rod and main bearings until crankcase oil from the oil pump can reach the journals, which will sling off the oil and lubricate other moving parts inside the engine. And with splash lubrication, crankcase oil is on the journals and other moving parts inside the engine as soon as the engine revs up.

When installing the Kohler K361 or M16 piston and rings in the cylinder, install with the notch facing toward the flywheel end of the block. These is because the wrist pin is offset in the piston, due to the cylinder bore is so large compared to the smaller engines, Kohler moved the the cylinder offset with the centerline of the main bearings. But the K241, M10, K301, M12, K321 and M14 pistons installs either way because the wrist pin is centered in the piston cylinder is centered with the centerline of the main bearings. To lessen the chance of blow-by during engine break-in, don't forget to offset or stagger the ring end gaps 120º-180º. And apply plenty of clean high detergent motor oil (with zinc additive) on the cylinder wall and piston rings before installing the piston assembly in the block. Then use a quality-made piston ring compressor tool. If the original clamping strap on the ring compressor breaks from metal fatigue due to repeated uses, it can be replaced with a large stainless steel automotive radiator hose clamp, and the ring compressor can still be used multiple times to fully compress the rings with a medium size screwdriver. Or if a manufactured ring compressor isn't available, it can be fabricated out of flat and clean (no paint, rust, etc.) 2" wide x 14" long (more or less, depending on the diameter of the piston) x 16 gauge sheet metal (air conditioning/heating duct tin works excellent) with a large stainless steel automotive radiator hose clamp. And be sure that everything is absolutely clean before installing the piston assembly in the cylinder!

FYI - The only type of piston with a notch or arrow on top are the ones with an offset wrist pin. The arrow or notch always installs toward the flywheel end on a small engine or harmonic balancer end or front of an automotive engine to place less strain on the piston skirts. With these type of pistons, the factory made the cylinder(s) larger and they bored them offset with the center-line of the main bearings. This is how the factory can put bigger pistons in larger engines and make more cubic inches without enlarging the engine block itself. Kohler K341, K361, older Chevy V8's, etc. have offset cylinders with an offset wrist pin in the pistons. And pistons with no notch or arrow on top have the wrist pin centered. These pistons can be installed in either direction because the cylinders are centered with the centerline of the main bearings.

Use a heavy wooden dowel or the wooden or rubber end of the handle of a medium-sized hammer to gently drive the piston into the cylinder. Be sure that the connecting rod is aligned with the crank journal as the piston is driven into the cylinder! If the piston stops going into the cylinder for any reason, stop to see what is stopping it. Don't just keep pounding it!

Piston ring technology has progressed a lot in recent years. Many ordinary small engines and automotive engines nowadays have thinner rings, and the rings place less tension against the cylinder wall. This is mainly to improve fuel economy and reduce exhaust emissions. It also helps the engine produce more power. Also, the engine idles smoother and revs up quicker.

Chrome VS Cast Iron Rings -

Some ring sets comes with the top ring having a chrome outer edge. Personally, I never experienced any differences between using a chrome ring or a cast iron ring. It seems that as long as the oil is changed regularly, a clean air filter is installed and the engine runs cool, one ring lasts just as long as the other. Because incoming dirt in the air intake system and in the oil, and overheating of the combustion chamber are the biggest killer of quality piston rings.

The top ring has either a chrome edge (OEM) or is 100% chrome (aftermarket). It's rarely 100% cast iron (black in color). The 2nd ring is usually 100% cast iron (black in color). Or, in rare cases, it could have a chrome edge, too. In either case, the manufacturer place the rings in their appropriate pouch (paper packaging) in the order they install on the piston.

Wrist Pin Retaining Snap Rings -

For high performance use (especially wide open throttle operation), use [the proper size] internal snap rings instead of the OEM retaining clips to retain the wrist pin in the piston. Because OEM retaining clips can wear excessively and on rare occasions, they've have been known to come loose at open RPM.

If you had the cylinder in your engine block bored oversize, before installing the piston/rod assembly in the cylinder, always clean the cylinder wall with warm soapy water and use a clean cloth that's white in color to see and to remove the microscopic metal dust that get lodged in the cross-hatch honing process of the cylinder wall. (Machine shops do not do this.) The metal will, more than likely, cause the rings to wear prematurely if this is not done. After cleaning, allow the cylinder to air-dry.

FYI - HONING a cylinder means to make it oversize for an oversized piston and rings assembly. (.010", .020" or .030") But DEGLAZING a cylinder means to roughen up the smooth surface to create more or less 60º cross-hatch lines. The cross-hatch lines act as tiny oil reservoirs to lubricate the rings so they can wear-in properly.

The Correct Way to Install Piston Rings -

First of all, instructions on how to install rings on the piston correctly should be in the box or package they came in. But if there is no slip of paper, then refer to the engine manufacturer's repair manual. Despite what the Kohler manual says, always install piston rings as indicated in the installation drawing that originally came with the rings. Because different manufacturers have their own way of how their rings should be installed and how the rings operate in the cylinder. And if you're wondering if there's any certain "tricks" when installing chrome rings on the piston or breaking them in, well, there really isn't any. Just install them as you would with ordinary cast iron rings. Being chrome rings are made of much harder material, it just takes longer for them to seat, they hold up to heat better, and they last a lot longer. Go here for more information: http://www.totalseal.com/howdoo.html. And if no repair manual is available, then refer to the instructions below.

If there's only one ring with a shiny edge, it's the top ring. It has a chrome edge to last longer. If it has a bevel on the inside, it goes upward. But if there's no bevel, it can be installed either way. If the 2nd (middle) ring has a chrome edge also, and if it has a bevel, it faces upward. But if it doesn't have a chrome edge, the bevel faces downward. If it has a step on the outer edge, it faces downward. And stamping (the word TOP or .010, .020 or .030) or a paint spot on the ring(s) ALWAYS face upward.

And the cylinder wall and new piston rings should always be lubricated with high detergent motor oil containing zinc to prevent the rings from rubbing against the cylinder wall due to friction, which can cause extreme heat and the rings to wear excessively and possibly wear the cylinder wall, too. Deglazing of the cylinder wall is necessary too, which creates shallow 60º cross-hatch lines to provide a "reservoir" for the rings to receive plenty of oil while they wear-in with the cylinder wall.

Apply oil or grease on the wrist pin and then install the connecting rod on the piston. NOTE: If the piston has a notch on the top (16hp and 18hp OHV engines), install the rod to the piston with the oil hole in the cap facing toward the camshaft. Make sure the match marks are aligned on the rod and cap!

Next, install the rings on the piston in their correct order according to the provided instructions or refer to the drawing to the right -> for correct piston ring installation. è

Installation of rings on the piston are as follows:

1. The bottom ring [set] (oil lubricator) and expander, if used, goes on first.
2. The middle ring (oil scraper) and expander, if used, goes on second.
3. Then the top ring (compression) goes on last. (The top ring rarely use an expander.)

Never attempt to install piston rings on the piston in the reverse order or they might break upon installation! Install the rings in the order as follows: (The below Ê applies to all 4-cycle piston-powered air-cooled and liquid-cooled engines, being a small engine, automotive, diesel, airplane, etc.)

1. The bottom ring [set] usually have no particular (upward or downward) way of installing, as they don't flex either way. If it's a three-piece ring, the expander installs first and butts end to end. The ends do not over-lap. The expander "expands" the two thin oil lubricator rings so they can apply more pressure against the cylinder wall to work better.
2. Make sure the middle or 2nd (middle) ring is installed correctly! This step is very important! This particular ring actually flexes. It has a slight angle on the outer edge that "scrapes" the oil from the cylinder wall on its way down and glides over the oil on its way up. If this ring isn't installed correctly or right-side-up, the engine will smoke a lot and use lots of oil. For most middle rings, the bevel (inside angle) faces downward. But for a chrome-edge 2nd (middle) ring, the bevel faces upward. However, if there's a dot (punch mark) or the word TOP or PIP laser-etched on the ring, it faces upward. And if the middle ring came with an expander (rippled spring-like ring), install it under the ring. It helps to stabilize the piston in the cylinder.
   • NOTE: If the middle ring is installed wrong side up or upside-down, and if the engine smokes a lot out the exhaust, this ring can be removed and reinstalled right side up. The rings can be reused because very little wear has occurred to them. There is no need to purchase another new set of rings due to improper installation of just one ring. Because installing new rings incorrectly doesn't necessarily cause them to wear more, they just cause the engine to smoke. If by chance the 2nd (middle) ring isn't installed upside-down, and the engine still smokes out the exhaust after the rebuild, then perhaps the crankcase breather is installed the wrong way. This will cause air pressure within the crankcase to build up, and be forced out through the ring end gaps along with the oil.
   • If there's no specific instructions on how to install the middle ring, and if a powerful magnifying glass isn't available to see the angle on the outer edge, then lightly rub the outer edge of the ring side to side against a flat piece of ceramic tile at an exact 90° angle. You should see a shiny area on one side of the angle. Mark the ring so the shiny area will face downward when installing the ring on the piston.
3. And as for the top ring, if it has square edges with no bevel, then there's no certain way how it installs on the piston, being it just holds the compression. And just like the 2nd (middle) ring, if there's a dot (punch mark) or the word TOP laser-etched on the ring, it faces upward.
4. IMPORTANT: If the second and bottom piston rings come with an expander, which is a wavy, thin metal spring device that is placed under a ring to hold it snugly against the cylinder wall, definitely install it/them, too! If the expander is left out under the second ring, the engine may burn oil and blow blue smoke out the exhaust, or if the expander is left out under the oil lubricator ring, insufficient lubrication may result to the cylinder wall and the two upper rings could wear prematurely. The top ring rarely use an expander.

If a single or two cylinder small engine burns oil and blows bluish-smoke out the exhaust, the following are the things that can cause it to smoke:

1. Worn piston, resulting in worn rings. Solution: Rebuild engine with a new piston and rings.
2. If the engine was recently rebuilt, perhaps the 2nd (oil control) ring(s) on the piston(s) are/is installed incorrectly with wrong side up or toward top of piston. Solution: remove 2nd ring, a reinstall correctly with right side up or toward top of piston.
3. Crankcase breather reed valve worn beyond specifications or damaged, or assembly installed in reverse, or the breather hose/tube is pinched, collapsed or clogged. Solution: Replace parts or repair as needed.
4. Leaking crankshaft oil seal. Solution: Install new oil seal with oil grease on rubber lip to prevent premature wear.
5. Small air gap between the two crankcase halves where it wasn't sealed properly with silicone sealant. (Kohler opposed twin cylinder engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 or MV20 only.) Solution: Split crankcase and reseal entire circumference of crankcase halves with a thin bead of clear RTV silicone adhesive sealant.

Referring to possibilities 2, 3 and 4, as the engine runs, outside air is drawn inside the crankcase through wherever the opening is, and crankcase oil blocks the opening from the inside preventing the air from escaping, and being this happens continuously in a pulsating effect, air pressure builds up inside the crankcase and the only place it can escape is through the piston ring gaps, which will take some crankcase oil with it as it exits the combustion chamber(s).

The Differences Between "Deglaze", "Hone" and "Bore" an Engine Cylinder -

Deglaze the Cylinder Wall -

Deglaze is roughing up or creating cross-hatch lines on the cylinder wall surface for proper new ring wear-in. Cylinder deglazing is performed with either a non-adjustable/spring-loaded ball-type, commonly known as the Flexstone Deglazer (also called a dingleberry hone), or the adjustable/spring-loaded type (to place more or less pressure against the cylinder wall) with three long, narrow stones, commonly known as the Rigid Cylinder Deglazer. These stones create shallow grooves in the cross-hatch lines. The flexstone deglazer can get into places on the cylinder wall where the rigid cylinder deglazer stones can't. And of course, the piston rings will only make contact with the high areas on the cylinder wall. Anyway, the deglazing process removes the "glaze" or shiny, slick surface that's on a used cylinder wall, and when moved up and down quickly, the deglazing process creates a ±60º cross-hatch pattern or tiny grooved lines, which act as a reservoir to retain oil so the rings can be better lubricated and wear-in with less friction for longer life. A smooth, slick cylinder wall can cause piston ring and cylinder scuffing. Also, depending on how much metal is removed or ground away, deglazing may enlarge the cylinder diameter as much as .003". Deglazing stones come in four grits: coarse; 100 grit, medium: 220 grit, fine; 320 grit, and super fine: 400 grit. Although the deglazing stone tool is smaller in size, automotive brake master and wheel cylinders also require deglazing before installing a new overhaul kit. Deglazing stone tools can be used with a lightweight power drill or drill press. NOTE: Before installing new rings, a cylinder wall should always be deglazed, then thoroughly cleaned afterwards.

Despite how nice and smooth the cylinder wall may be, or if there's a few light scratches on the cylinder wall, it'll always a good idea to "break the glaze" with a 3/8" or 1/2" hand-held power drill and a flex-hone (with ball stones) of the correct size or a spring-loaded cylinder deglazer (with straight stones) to deglaze the cylinder wall. If the crankshaft and cam is still in the block, either remove them before deglazing the cylinder wall, or if this is possible, place a clean rag over the crank and cam to protect them from the metal fragments. Be careful when removing the rag as to not get any metal fragments on the crank or cam.

Apply a lightweight lubricant such as Liquid Wrench or WD-40 on the cylinder wall. Place the deglazing stones midway in the cylinder and spin it at a fast speed while moving it up and down at the same time. Try to maintain full control of the deglazer tool at all times. Be careful not to allow it to come out of the cylinder or go down below the cylinder wall and hit something in the crankcase, causing breakage to the stones or damage to the tool. On the last few strokes, give it a quick up and down motion to produce a 60° crosshatch pattern. This only takes a few seconds to complete. The grooves in the crosshatch marks retains motor oil to properly lubricate and cool the new rings so they will wear-in quicker and last longer. After the deglazing process is complete, clean the cylinder wall with cleaning solvent, then use a minimum 1,000 PSI pressure washer to thoroughly clean the cylinder wall to remove any microscopic metal fragments left behind during the deglazing process. Then wipe a clean cloth (white in color) around the cylinder wall to see that the wall is free of the metal fragments. If the metal fragments are not removed, severe wear of the rings and piston will likely result in a short time. Remember - metal flake looks good in paint, not in oil.

For long-term storage of virtually any rebuilt engine or short block to prevent any rust build-up, many knowledgeable and experienced mechanics apply protective rust inhibitor oil spray, white lithium grease spray or automotive chassis grease on the piston rings, cylinder wall(s), rod and main journals, camshaft lobes, camshaft pin, and all other internal engine parts that make contact with each other. This provides a thin film that that seals out moisture, which protects vulnerable internal engine parts so they will not rust due to any condensation that may be present in the air. Because rust is the biggest enemy of internal engine parts. When the engine is first started, the grease will melt, and dissolve and mix with the crankcase oil, which will harm nothing. The reason grease works better than motor oil for long-term storage is because eventually the oil will seep past the ring gaps, and drain off of other internal engine parts, and down into the crankcase, and then all there'll be is a very thin coat of oil, or depending on the length of storage time, any oil at all, to protect the parts upon engine startup, which would likely cause excessive wear to valuable parts. In an engine with an oil pump, grease works better to provide longer lubrication of the rod and main bearings until crankcase oil from the oil pump can reach the journals, which will sling off the oil and lubricate other moving parts inside the engine. And with splash lubrication, crankcase oil is on the journals and other moving parts inside the engine as soon as the engine revs up.

Hone a Cylinder -

Honing is slight grinding or wearing away of a cylinder wall with an expandable rotary manually adjustable rack and pinion honing stone tool to make the cylinder oversize for a .010" or possibly a .020" oversize piston and rings. Honing is the final step after the boring process to slightly enlarge the cylinder further a few thousandths of an inch so it'll be within specs of the oversize piston and rings assembly. Just like deglazing, when moved up and down quickly, honing creates cross-hatch lines or tiny grooves, which retains oil and allow the rings to be better lubricated and wear-in with less friction for longer life. When honing (enlarging) a cylinder for an oversize piston and rings, start with a coarse stones for a rapid cut, then finish the honing process with fine stones to create shallow grooves in the cross-hatch lines. This will allow the cylinder to increase lesser in diameter when the rings wear-in. Also, honing a cylinder and honing a connecting rod are a similar process because it only removes a few thousandths of an inch from each part. Plus, it makes the big hole in the rod a perfect circle. Boring a connecting rod is when a lot of metal is removed for bearing inserts. And connecting rods are never deglazed. Cylinder honing stones come in four grits: coarse; 120 grit, medium; 180 grit, fine; 220 grit, and super fine; 320 grit. The cylinder honing tool can be used with a heavy duty electric, or better yet, a heavy duty 1/2" pneumatic air drill with a minimum 40 gallon air compressor tank, or it is integrated as part of an elaborate machine.

Bore a Cylinder -

Boring is necessary when removing an excessive amount of metal from a cylinder wall for an extremely large/oversize piston and rings assembly, or for installation of a cylinder sleeve. If the cylinder is bored within a few thousandths of an inch of the specified size piston to wall clearance, the cylinder hone is used to finish enlarging the cylinder and can produce the cross-hatch pattern for proper ring wear-in. But if the cylinder is bored for the specified piston to wall clearance, a flexstone or rigid cylinder deglazer is used to produce the cross-hatch pattern for proper ring wear-in. A boring bar is part of an elaborate machine, but it can also be adapted for use in a large milling machine.

FYI - Boring a STD size cylinder to a maximum of .030" and installing a new .030" oversize piston and rings will not help to increase the power much at all. Engine dyno tests have shown that this will only give the engine about 1/10th more horsepower, which would be very unnoticeable with heavy use or on the track. If the cylinder wall in an engine is not scored or worn, then it can be deglazed and a new STD size (or whatever oversize, if the engine was previously rebuilt) piston and rings can be installed. But if the cylinder is STD size and needs to be bored to the next oversize (.010", .020" or .030"), then a new matching oversize piston and rings will need to be used. What increases engine horsepower and torque substantially is using a crankshaft with a longer stroke. (Click or tap here for an explanation of why a longer stroke works better.) But these engines isn't capable of this.

Nothing else may be needed to be done to the engine, except for perhaps perform a professional valve job and tune-up. Or better yet, install electronic ignition. Also, many opposed twin cylinder engines have inadequate valve clearances and this robs the engine of proper operation and valuable power. Set the valve clearances at .006" for the intake and .010" for the exhaust. After performing the tune-up and resetting the valve clearances to factory specifications, the engine should start quicker, idle better, accelerate with less hesitation and produce more power and torque at any RPM.

And I wouldn't recommend using a heavy cast iron block Kohler engine in a go-kart, older small all terrain vehicle or motorcycle. For reasons being, not only is the Kohler engines made of cast iron, which is extremely heavy compared to an aluminum block [V-twin or motorcycle] engine, the cast iron block Kohler are also flathead engines. They're designed for torque, or lugging power, and even if built to the max, a Kohler flathead would be VERY sluggish upon take-off and lack adequate power when accelerated, especially on hills. The vehicle would have to be geared so low, it wouldn't be any fun enjoyment or for practical use. This is why all (newer) motorcycles, ATVs, and all other small all terrain vehicle engines have a short stroke (for speed), made of aluminum, with an OHV design, to be quick, lightweight and produce lots of power. [Top of Page]

For 100% accuracy, before a machinist hones a cylinder for an oversized piston and rings, the block should be warmed at room temperature, and the finish honing process should also be performed at room temperature. And just before the final few thousandths of honing, the block should be allowed to air-cool due to heat expansion from the friction during the honing process, and then the cylinder bore should be accurately measured again. If it measures too small, it will need to be honed slightly larger to the proper piston to wall clearance. Remember, hone once and measure twice! Because it's a lot easier to remove metal than replace it. Furthermore, due to metal expansion when hot and shrinkage when cool, engine parts should never be machined when cold, or in a cool or cold environment.

Advertisement: | Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

NOTE: All parts listed below are NEW, unless otherwise stated. We do not sell cheap junk! As a matter of fact, most OEM Kohler parts are made in China now. Kohler owns some of the factories in China that make the parts. And most aftermarket parts are also made by Kohler in China. Kohler just place the part(s) in a generic box and sell them for less money. So when purchasing a genuine OEM Kohler part that comes in a box with the Kohler name on it, you're really just paying more money for the name. And as far as some parts being no longer available - either the parts didn't sell well or the EPA is trying to phase out parts for the old cast iron block flathead engines because they produce more air pollution than the newer OHV engines.
Kohler engine models K90/K91 Ring Sets, and Piston and Ring Sets (includes wrist pin, retaining clips). Rings made of high grade cast iron for durability. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. Fits K90/K91 engines with 2.375" cylinder bore. Also replaces Briggs & Stratton part #'s 294232, 295657 (3hp), and Clinton part #'s 233112500, 233122500. High quality aftermarket. Same appearance and quality as OEM Kohler part # 220801-S. $13.00 per set, plus shipping & handling. OEM Kohler part # 220801-S. $50.00 per set, plus shipping & handling. STD Size Piston and Ring Set. Fits K90/K91 engines with 2.375" cylinder bore. OEM Kohler part # 46 874 01-S. $182.85 per set, plus shipping & handling. .003" Oversize Piston and Ring Set. Fits K90/K91 engines with 2.378" cylinder bore. OEM Kohler part # 46 874 02-S. $213.50 per set, plus shipping & handling. .010" (.25mm) Oversize Ring Set Only. Fits K90/K91 engines with 2.385" cylinder bore. OEM Kohler part # 220802-S. Also replaces Briggs & Stratton part # 294224 (NLA). $64.00 per set, plus shipping & handling. .010" (.25mm) Oversize Piston and Ring Set. Fits K90/K91 engines with 2.385" cylinder bore. OEM Kohler part # 46 874 03-S. $213.50 per set, plus shipping & handling. .020" (.50mm) Oversize Ring Set Only. Fits K90/K91 engines with 2.395" cylinder bore. OEM Briggs & Stratton part # 294225. Also replaces Kohler part # 220803-S (NLA). $60.00 per set, plus shipping & handling. .020" oversize (2.395" cylinder bore. OEM Kohler part # 46 874 04-S. $213.50 per set, plus shipping & handling. .030" (.75mm) Oversize Ring Sets Only. Fits K90/K91 engines with 2.405" cylinder bore. OEM Briggs & Stratton part # 294226. $60.00 per set, plus shipping & handling. OEM Kohler part # 220804-S. $81.80 per set, plus shipping & handling. .030" (.75mm) Oversize Piston and Ring Set. Fits K90/K91 engines with 2.405" cylinder bore. OEM Kohler part # 46 874 05-S. $213.50 per set, plus shipping & handling.
Kohler engine models K141, K160/K161, KV161, L160/L161, L181, K181 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). These are for the smaller 2-7/8" diameter cylinder bore. Cylinder can be bored to 2-15/16", and the bigger piston and rings listed below can be used. Rings made of high grade cast iron for durability. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Set Only. Discontinued Kohler part # 231424-S. NOS (New Old Stock). Price depends on source and availability. STD Size Piston and Ring Set. Fits K141, K160 and early K161 engines with 2.875" cylinder bore. OEM Kohler part # 41 874 01-S. $188.20 each, plus shipping & handling. .010" (.25mm) Oversize Ring Set Only. Fits K141, K160 and early K161 engines with 2.885" cylinder bore. OEM Kohler part # 231425-S. $96.60 per set, plus shipping & handling. .010" (.25mm) Oversize Piston and Ring Set. Discontinued Kohler part # 41 874 02-S. NOS (New Old Stock). Price depends on source and availability. .020" (.50mm) Oversize Ring Set Only. Fits K141, K160 and early K161 engines with 2.895" cylinder bore. OEM Kohler part # 231426-S. $100.70 per set, plus shipping & handling. .020" (.50mm) Oversize Piston and Ring Set. Discontinued Kohler part # 41 874 03-S. NOS (New Old Stock). Price depends on source and availability. .030" (.75mm) Oversize Ring Set Only. Discontinued Kohler part # 231427-S. NOS (New Old Stock). Price depends on source and availability. .030" (.75mm) Oversize Piston with Rings Assembly. Discontinued Kohler part # 41 874 04-S. NOS (New Old Stock). Price depends on source and availability.
Kohler K-series and Magnum engine models K141, K160/K161, KV161, L160/L161, L181, K181 and M8 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). These are for the bigger 2-15/16" diameter cylinder bore. Rings made of high grade cast iron for durability. FYI - When the 2-15/16" piston and rings assembly is used in the K141, K160/K161, KV161, L160/L161 engines, the same connecting rod and crankshaft can be used. The rotating assembly will not need to be rebalanced. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.938" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 232575-S. $16.00 per set,plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 232575-S. $60.10 per set,plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 41 108 01-S. $61.50 per set,plus shipping & handling. STD Size Pistons with Matching Ring Set. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.938" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 41 874 05-S. $44.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 41 874 05-S. $181.45 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 41 874 10-S. $156.40 each, plus shipping & handling. .003" Oversize Pistons with Matching Ring Set. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.941" cylinder bore. K-series cast piston with rings. OEM Kohler part # 41 874 06-S. $193.30 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 41 874 11-S. $151.25 each, plus shipping & handling. .010" (.25mm) Oversize Ring Sets Only. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.948" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 232576-S. $11.00 per set,plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 232576-S. $54.00 per set,plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 41 108 02-S. $65.65 per set,plus shipping & handling. .010" (.25mm) Oversize Pistons with Matching Ring Set. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.948" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 41 874 07-S. $40.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 41 874 07-S. $181.45 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 41 874 12-S. $151.10 each, plus shipping & handling. .020" (.50mm) Oversize Ring Sets Only. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.958" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 232577-S. $30.00 per set,plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 232577-S. $78.80 each, plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 41 108 03-S. $66.00 per set,plus shipping & handling. .020" (.50mm) Oversize Pistons with Matching Ring Set. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.958" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 41 874 08-S. $50.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 41 874 08-S. $193.45 each, plus shipping & handling. Mahle piston and rings. Discontinued Kohler part # 41 874 13-S. NOS (New Old Stock). Price depends on source and availability. .030" (.75mm) Oversize Ring Sets Only. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.968" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 232578-S. $13.00 per set,plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 232578-S. $78.95 per set,plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 41 108 04-S. $66.00 per set,plus shipping & handling. .030" (.75mm) Oversize Pistons with Matching Ring Set. Fits K141, K160/K161, L160/L161, L181, K181 and M8 engines with 2.968" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 41 874 09-S. $41.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 41 874 09-S. $188.30 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 41 874 14-S. $151.25 each, plus shipping & handling.
Kohler K-series and Magnum engine models K241, M10 and K482 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). (The K241, M10 and K482 engines use the same piston and rings.) Priced per cylinder. Rings made of high grade cast iron for durability. Compression height is 1.63". Being the wrist pin is centered, these pistons can be installed in either direction. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. Fits K241, M10 and K482 engines with 3.250" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 235287-S. $22.00 per set, plus shipping & handling. OEM Kohler part # 235287-S. $72.20 per set, plus shipping & handling. STD Size Pistons with Matching Ring Set. Fits K241, M10 and K482 engines with 3.250" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 47 874 01-S. $43.00 each, plus shipping & handling. OEM Kohler part # 47 874 01-S. $216.00 each, plus shipping & handling. .003" Oversize Cast Piston and Ring Sets. Fits K241, M10 and K482 engines with 3.253" cylinder bore. OEM Kohler part # 47 874 02-S. $221.00 each, plus shipping & handling. .010" (.25mm) Oversize Ring Sets Only. Fits K241, M10 and K482 engines with 3.260" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 235288-S. $19.00 per set, plus shipping & handling. OEM Kohler part # 235288-S. $83.00 per set, plus shipping & handling. .010" (.25mm) Oversize Pistons with Matching Ring Set. Fits K241, M10 and K482 engines with 3.260" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 47 874 03-S. $40.00 each, plus shipping & handling. OEM Kohler part # 47 874 03-S. $216.00 each, plus shipping & handling. .020" (.50mm) Oversize Ring Sets Only. Fits K241, M10 and K482 engines with 3.270" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 235289-S. $14.00 per set, plus shipping & handling. OEM Kohler part # 235289-S. $95.14 per set, plus shipping & handling. .020" (.50mm) Oversize Pistons with Matching Ring Set. Fits K241, M10 and K482 engines with 3.270" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 47 874 04-S. $40.00 each, plus shipping & handling. OEM Kohler part # 47 874 04-S. $247.81 each, plus shipping & handling. .030" (.75mm) Oversize Ring Sets Only. Fits K241, M10 and K482 engines with 3.280" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 235290-S. $14.00 per set, plus shipping & handling. OEM Kohler part # 235290-S. $95.14 per set, plus shipping & handling. .030" (.75mm) Oversize Pistons with Matching Ring Set. Fits K241, M10 and K482 engines with 3.280" cylinder bore. High quality aftermarket. Same appearance and quality as OEM Kohler part # 47 874 05-S. $45.00 each, plus shipping & handling. OEM Kohler part # 47 874 05-S. $247.81 each, plus shipping & handling.
Kohler K-series and Magnum models K301, M12 and K532 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). (The K301, M12 and K532 engines use the same piston and rings.) Priced per cylinder. Rings made of high grade cast iron for durability. Compression height is 1.7". Being the wrist pin is centered, these pistons can be installed in either direction. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. Fits K301, M12 and K532 engines with 3.375" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 01-S. $16.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 01-S. $69.59 per set, plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 47 108 01-S. $91.95 per set, plus shipping & handling. STD Size Pistons with Matching Ring Set. Fits K301, M12 and K532 engines with 3.375" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 47 874 06-S and 48 874 01-S. $39.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 47 874 06-S. $184.44 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 48 874 01-S. $288.99 each, plus shipping & handling. Mahle piston and rings. Discontinued Kohler part # 47 874 16-S. NOS (New Old Stock). Price depends on source and availability. .003" Oversize Piston and Ring Set. Fits K301, M12 and K532 engines with 3.378" cylinder bore. Mahle piston and rings. Discontinued Kohler part # 47 874 17-S. NOS (New Old Stock). Price depends on source and availability. .010" (.25mm) Oversize Ring Sets Only. Fits K301, M12 and K532 engines with 3.385" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 02-S. $18.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 02-S. $119.30 per set, plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 47 108 02-S. $102.75 per set, plus shipping & handling. .010" (.25mm) Oversize Pistons with Matching Ring Set. Fits K301, M12 and K532 engines with 3.385" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 47 874 08-S and 48 874 03-S. $57.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 47 874 08-S. $247.81 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 48 874 03-S. $228.89 each, plus shipping & handling. Mahle piston and rings. Discontinued Kohler part # 47 874 18-S. NOS (New Old Stock). Price depends on source and availability. .020" (.50mm) Oversize Ring Sets Only. Fits K301, M12 and K532 engines with 3.395" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 03-S. $18.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 03-S. $119.30 per set, plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 47 108 03-S. $83.03 per set, plus shipping & handling. .020" (.50mm) Oversize Pistons with Matching Ring Set. Fits K301, M12 and K532 engines with 3.395" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 47 874 09-S and 48 874 04-S. $46.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 47 874 09-S. $247.81 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 48 874 04-S. $228.99 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 47 874 19-S. $182.66 each, plus shipping & handling. .030" (.75mm) Oversize Ring Sets Only. Fits K301, M12 and K532 engines with 3.405" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 04-S. $18.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 04-S. $119.19 per set, plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 47 108 04-S. $83.03 per set, plus shipping & handling. .030" (.75mm) Oversize Pistons with Matching Ring Set. Fits K301, M12 and K532 engines with 3.405" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 47 874 10-S. $36.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 47 874 10-S. $247.81 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 47 874 20-S. $182.66 each, plus shipping & handling. .040" (1.0mm) Oversize High Quality Ring Set. Fits K301, M12 and K532 engines with 3.415" cylinder bore. Not available from Kohler. $30.00 each, plus shipping & handling. .040" (1.0mm) Oversize Cast Piston with High Quality Rings. Fits K301, M12 and K532 engines with 3.415" cylinder bore. Not available from Kohler. $75.00 each, plus shipping & handling.
Kohler K-series and Magnum models K321, M14 and K582 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). (The K321, M14 and K582 engines use the same piston and rings.) Priced per cylinder. Compression height is 1.7". Rings made of high grade cast iron for durability. And being the wrist pin is centered, these pistons can be installed in either direction. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. Fits K321, M14 and K582 engines with 3.500" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 05-S. $24.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 05-S. $101.23 per set, plus shipping & handling. Fits Magnum Mahle piston. Discontinued Kohler part # 47 108 05-S. NOS (New Old Stock). Price depends on source and availability. STD Size Pistons with Matching Ring Set. Fits K321, M14 and K582 engines with 3.500" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as Discontinued Kohler part # 47 874 11-S. $55.00 each, plus shipping & handling. Mahle piston and rings. Discontinued Kohler part # 47 874 21-S. NOS (New Old Stock). Price depends on source and availability. .003" Oversize Cast Piston and Ring Set. Discontinued Kohler part # 47 874 12-S. NOS (New Old Stock). Price depends on source and availability. .010" (.25mm) Oversize Ring Sets Only. Fits K321, M14 and K582 engines with 3.510" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 06-S. $18.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 06-S. $102.75 per set, plus shipping & handling. Fits Magnum Mahle piston. Discontinued Kohler part # 47 108 06-S. NOS (New Old Stock). Price depends on source and availability. .010" (.25mm) Oversize Pistons with Matching Ring Set. Fits K321, M14 and K582 engines with 3.510" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 47 874 13-S. $52.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 47 874 13-S. $247.81 each, plus shipping & handling. Mahle piston and rings. OEM Kohler part # 47 874 23-S. $301.81 each, plus shipping & handling. .020" (.50mm) Oversize Ring Sets Only. Fits K321, M14 and K582 engines with 3.520" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 07-S. $15.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 07-S. $119.30 per set, plus shipping & handling. Fits Magnum Mahle piston. OEM Kohler part # 47 108 07-S. $106.22 per set, plus shipping & handling. .020" (.50mm) Oversize Pistons with Matching Ring Set. Fits K321, M14 and K582 engines with 3.520" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as Discontinued Kohler part # 47 874 14-S. $49.00 each, plus shipping & handling. Mahle piston and rings. Discontinued Kohler part # 47 874 24-S. NOS (New Old Stock). Price depends on source and availability. .030" (.75mm) Oversize Ring Sets Only. Fits K321, M14 and K582 engines with 3.530" cylinder bore. Fits K-series cast piston. High quality aftermarket. Same appearance and quality as OEM Kohler part # 48 108 08-S. $20.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 48 108 08-S. $119.30 per set, plus shipping & handling. Fits Magnum Mahle piston. Discontinued Kohler part # 47 108 08-S. NOS (New Old Stock). Price depends on source and availability. .030" (.75mm) Oversize Pistons with Matching Ring Set. Fits K321, M14 and K582 engines with 3.530" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 47 874 15-S. $63.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 47 874 15-S. $247.81 each, plus shipping & handling. Mahle piston and rings. Discontinued Kohler part # 47 874 25-S. NOS (New Old Stock). Price depends on source and availability. .040" (1.0mm) Oversize High Quality Ring Set. Fits K321, M14 and K582 engines with 3.415" cylinder bore. Not available from Kohler. $30.00 each, plus shipping & handling. .040" (1.0mm) Oversize Cast Piston with High Quality Rings. Fits K321, M14 and K582 engines with 3.415" cylinder bore. Not available from Kohler. $80.00 each, plus shipping & handling.
Kohler K-series and Magnum engine models K341, M16 and K361 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). (The K341, M16 and K361 engines use the same piston and rings.) Compression height is 1.7". Rings made of high grade cast iron for durability. Wrist pin is offset to reduce piston slap. Therefore, piston installs with notch facing flywheel. IMPORTANT: Check ring end gaps and piston thrust face for proper clearance before installing to prevent rings from galling the cylinder wall when hot and piston from seizing in the cylinder when hot. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. Fits K341, M16 and K361 engines with 3.750" cylinder bore. High quality aftermarket. Fits K-series cast piston. Same appearance and quality as OEM Kohler part # 45 108 06-S. $39.00 per set, plus shipping & handling. Fits K-series cast piston. OEM Kohler part # 45 108 06-S. $94.09 per set, plus shipping & handling. Fits Magnum Mahle forged piston. OEM Kohler part # 41 108 01-S. $67.18 per set, plus shipping & handling. STD Size Pistons with Matching Ring Set. Fits K341, M16 and K361 engines with 3.750" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 45 874 01-S. $102.40 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 45 874 01-S. $290.59 each, plus shipping & handling. Magnum Mahle forged piston with rings. Discontinued Kohler part # 45 874 11-S. NOS (New Old Stock). Price depends on source and availability. .003" Oversize Cast Piston and Ring Sets. Fits K341, M16 and K361 engines with 3.753" cylinder bore. K-series cast piston with rings. OEM Kohler part # 45 874 02-S. $400.30 each, plus shipping & handling. Magnum Mahle forged piston with rings. Discontinued Kohler part # 45 874 12-S. NOS (New Old Stock). Price depends on source and availability. .010" (.25mm) Oversize Ring Sets Only. Fits K341, M16 and K361 engines with 3.760" cylinder bore. Fits K-series cast piston. OEM Kohler part # 45 108 07-S. $98.63 per set, plus shipping & handling. Not available in aftermarket. Fits Magnum Mahle forged piston. OEM Kohler part # 45 108 11-S. $143.45 per set, plus shipping & handling. .010" (.25mm) Oversize Pistons with Matching Ring Set. Fits K341, M16 and K361 engines with 3.760" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 45 874 03-S. $96.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 45 874 03-S. $290.59 each, plus shipping & handling. Magnum Mahle forged piston with rings. OEM Kohler part # 45 874 13-S. $317.30 each, plus shipping & handling. .020" (.50mm) Oversize Ring Sets Only. Fits K341, M16 and K361 engines with 3.770" cylinder bore. Fits K-series cast piston. OEM Kohler part # 45 108 08-S. $98.63 per set, plus shipping & handling. Not available in aftermarket. Fits Magnum Mahle forged piston. OEM Kohler part # 45 108 12-S. $106.80 per set, plus shipping & handling. .020" (.50mm) Oversize Pistons with Matching Ring Set. Fits K341, M16 and K361 engines with 3.770" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as OEM Kohler part # 45 874 04-S. $96.00 each, plus shipping & handling. K-series cast piston with rings. OEM Kohler part # 45 874 04-S. $322.20 each, plus shipping & handling. Magnum Mahle forged piston with rings. Discontinued Kohler part # 45 874 14-S. NOS (New Old Stock). Price depends on source and availability. .030" (.75mm) Oversize Ring Sets Only. Fits K341, M16 and K361 engines with 3.780" cylinder bore. Fits K-series cast piston. NOS Discontinued Kohler part # 45 108 09-S. $96.00 per set, plus shipping & handling. (When available.) Fits Magnum Mahle forged piston. OEM Kohler part # 45 108 13-S. $106.80 per set, plus shipping & handling. .030" (.75mm) Oversize Pistons with Matching Ring Set. Fits K341, M16 and K361 engines with 3.780" cylinder bore. High quality aftermarket. K-series cast piston with rings. Same appearance and quality as Discontinued Kohler part # 45 874 05-S. $96.00 each, plus shipping & handling. Magnum Mahle forged piston with rings. Discontinued Kohler part # 45 874 15-S. NOS (New Old Stock). Price depends on source and availability. .040" (1.0mm) Oversize High Quality Ring Set. Fits K341, M16 and K361 engines with 3.790" cylinder bore. Not available from Kohler. $60.00 each, plus shipping & handling. .040" (1.0mm) Oversize Cast Piston with High Quality Rings. Fits K341, M16 and K361 engines with 3.790" cylinder bore. Not available from Kohler. $120.00 each, plus shipping & handling. [Return To Previous Paragraph, Section or Website]
Ring Sets Only, and Pistons with Rings. Pistons include wrist pin and clips. Fits Kohler opposed twin cylinder engine models KT17 (first design), KT17 Series II, MV16, M18 and MV18. The KT17 (first design), KT17 Series II, MV16, M18 and MV18 pistons all have the same dimensions, same wrist pin diameter (.6247"-.6249") and same compression height (1.125"), and all use the same rings. The only difference is the OEM KT17 and KT17 Series II pistons are cast aluminum, and the OEM MV16, M18 and MV18 pistons are forged, and made by Mahle. Priced per cylinder. To maintain engine balance and reduce vibration, two sets of matching oversize pistons and rings are required. IMPORTANT: Check and set ring end gaps for proper clearance before installing to prevent rings from expanding when hot and galling the cylinder wall. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD Size Ring Sets Only. (3.125" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 09-S. $30.00 per set (for one cylinder), plus shipping & handling. OEM Kohler part # 52 108 09-S. $90.35 per set (for one cylinder), plus shipping & handling. STD Size Pistons with Rings. (3.125" diameter cylinder bore.) Cast Piston with Rings. High Quality aftermarket. Replaces Kohler part # 52 875 01-S. $60.00 each, plus shipping & handling. Cast Piston with Rings. OEM Kohler part # 52 874 01-S. $256.90 each, plus shipping & handling. Mahle Piston with Rings. High Quality aftermarket. Replaces Kohler part # 52 875 01-S. $60.00 each, plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 874 01-S. $256.90 each, plus shipping & handling. .010" (.25mm) Oversize Ring Sets Only. (3.135" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 10-S. $30.00 per set (for one cylinder), plus shipping & handling. OEM Kohler part # 52 108 10-S. $88.35 per set (for one cylinder), plus shipping & handling. .010" (.25mm) Oversize Pistons with Rings. (3.135" diameter cylinder bore.) Cast Piston with Rings. High Quality aftermarket. Replaces Kohler part # 52 875 03-S . $60.00 each, plus shipping & handling. Cast Piston with Rings. OEM Kohler part # 52 874 03-S. $257.15 each, plus shipping & handling. Mahle Piston with Rings. High quality aftermarket. Replaces Kohler part # 52 108 10-S. $30.00 per set (for one cylinder), plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 108 10-S. $88.35 per set (for one cylinder), plus shipping & handling. .020" (.50mm) Oversize Ring Set. (3.145" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 11-S. $40.00 per set (for one cylinder), plus shipping & handling. OEM Kohler part # 52 108 11-S. $99.40 per set (for one cylinder), plus shipping & handling. .020" (.50mm) Oversize Pistons with Rings. (3.145" diameter cylinder bore.) Cast Piston with Rings. OEM Kohler part # 52 874 04-S. $293.00 each, plus shipping & handling. Mahle Piston with Rings. High Quality aftermarket. Replaces Kohler part # 52 874 04-S. $75.00 each, plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 874 04-S. $293.00 each, plus shipping & handling. .030" (.75mm) Oversize Ring Set. (3.155" diameter cylinder bore.) High quality aftermarket. Replaces discontinued Kohler part # 52 108 12-S. $40.00 per set (for one cylinder), plus shipping & handling. .030" (.75mm) Oversize Pistons with Rings. (3.155" diameter cylinder bore.) Cast Piston with Rings. OEM Kohler part # 52 874 01-S. $355.65 each, plus shipping & handling. Mahle Piston with Rings. High Quality aftermarket. Replaces Kohler part # 52 874 05-S. $75.00 each, plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 874 05-S. $345.50 each, plus shipping & handling. Ring Sets Only, and Pistons with Rings. Pistons include wrist pin and clips. Fits Kohler engine models KT19 Series II, KT21, M20 and MV20. The KT19 Series II, KT21, M20 and MV20 pistons all have the same dimensions, same wrist pin diameter (.7499"-.7501") and same compression height (1.1875"), and all use the same rings. The only difference is the OEM KT19 Series II and KT21 pistons are cast aluminum, and the OEM M20 and MV20 pistons are forged, and made by Mahle. KT19 (first design) pistons with 5/8" wrist pin and 1.1875" compression height no longer available. Priced per cylinder. To maintain engine balance and reduce vibration, two sets of matching oversize piston and rings are required. STD Size Ring Sets Only. (3.125" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 09-S. $30.00 per set (for one cylinder), plus shipping & handling. OEM Kohler part # 52 108 09-S. $76.90 per set (for one cylinder), plus shipping & handling. STD Size Pistons with Rings. (3.125" diameter cylinder bore.) Cast piston discontinued Kohler part # 52 874 06-S. Not available in aftermarket. L Mahle Piston with Rings. High quality aftermarket. Replaces Kohler part # 52 874 16-S. $75.00 each (for one cylinder), plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 874 16-S. $173.83 each, plus shipping & handling. .010" (.25mm) Oversize Ring Sets Only. (3.135" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 10-S. $30.00 per set (for one cylinder), plus shipping & handling. OEM Kohler part # 52 108 10-S. $88.35 per set (for one cylinder), plus shipping & handling. .010" (.25mm) Oversize Pistons with Rings. (3.135" cylinder bore.) Cast Piston with Rings. OEM Kohler part # 52 874 08-S. $260.95 each, plus shipping & handling. Not available in aftermarket. L Mahle Piston with Rings. High quality aftermarket. Replaces Kohler part # 52 874 18-S. $75.00 each, plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 874 18-S. $168.53 each, plus shipping & handling. .020" (.50mm) Oversize Ring Set. (3.145" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 11-S. $40.00 per set (for one cylinder), plus shipping & handling. OEM Kohler part # 52 108 11-S. $99.40 per set (for one cylinder), plus shipping & handling. .020" (.50mm) Oversize Pistons with Rings. (3.145" diameter cylinder bore.) Cast Piston with Rings. OEM Kohler part # 52 874 09-S. $306.70 each, plus shipping & handling. Not available in aftermarket. L Mahle Piston with Rings. High quality aftermarket. Replaces Kohler part # 52 874 19-S. $75.00 each, plus shipping & handling. Mahle Piston with Rings. OEM Kohler part # 52 874 19-S. $163.90 each, plus shipping & handling. .030" (.75mm) Oversize Ring Set Only. (3.155" diameter cylinder bore.) High quality aftermarket. Replaces discontinued Kohler part # 52 108 04-S. $40.00 per set (for one cylinder), plus shipping & handling. .030" (.75mm) Oversize Piston with Rings. (3.155" diameter cylinder bore.) Cast Piston with Rings. Discontinued Kohler part # 52 874 10-S. NOS (New Old Stock). Price depends on source and availability. Mahle Piston with Rings. High quality aftermarket. Replaces discontinued Kohler part # 52 874 20-S. $75.00 each, plus shipping & handling.
5/8" Wrist Pin Retainers. Each fits Kohler engine models K141, K160/K161, KV161, L160/L161, L181, K181, M8, KT17 (first design), KT17 Series II, KT19 (first design), MV16, M18 and MV18. 5/8" Aftermarket Internal Snap Ring. Replaces Kohler part # 230004-S. $1.50/two, plus shipping & handling. 5/8" Wire Cir-Clip. OEM Kohler part # 230004-S. $4.95/two, plus shipping & handling. 3/4" Wrist Pin Retainers. Each fits Kohler engine models KT19 Series II, M20 and MV20. 3/4" Aftermarket Internal Snap Ring. Replaces Kohler part # 52 141 01-S. $2.00/two, plus shipping & handling. 3/4" Wire Cir-Clip. OEM Kohler part # 52 141 01-S. $5.40/two, plus shipping & handling. 7/8" Wrist Pin Retainers. Each fits Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361, K482, K532 and K582. 7/8" Aftermarket Internal Snap Ring. Replaces Kohler part # 47 018 01-S. $2.00/two, plus shipping & handling. 7/8" Wire Cir-Clip. OEM Kohler part # 47 018 01-S. $5.00/two, plus shipping & handling.
Cylinder head gasket. Fits Kohler engine models K90/K91. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. Click or tap here for cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below Ê. High quality aftermarket. Replaces Kohler part # 220124-S. $8.00 each, plus shipping & handling. OEM Kohler part # 220124-S. $10.14 each, plus shipping & handling.	Cylinder head gasket. Fits Kohler engine models K141, K160/K161, K181 and M8. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. Click or tap here for cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below Ê. High quality aftermarket. Replaces Kohler part # 41 041 10-S. $7.00 each, plus shipping & handling. OEM Kohler part # 41 041 10-S. $10.76 each, plus shipping & handling.
Cylinder head gasket. Fits Kohler engine models K241, M10, K301, M12, K321 and M14. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. Click or tap here for cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below Ê. High quality aftermarket. Replaces Kohler part # 47 041 15-S. $6.25 each, plus shipping & handling. OEM Kohler part # 47 041 15-S. $22.40 each, plus shipping & handling.	Cylinder head gasket. Fits Kohler engine models K341 and M16. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. Click or tap here for cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below Ê. High quality aftermarket. Replaces Kohler part # 45 041 17-S. $11.50 each, plus shipping & handling. OEM Kohler part # 45 041 17-S. $17.52 each, plus shipping & handling.
Cylinder head gasket. Fits Kohler engine model K361. Approximately .050" compressed thickness with steel fire ring. Doesn't need to be retorqued again once hot. Click or tap here for cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below. High quality aftermarket. Replaces discontinued Kohler part # 45 052 02-S and Cub Cadet/MTD part # KH-45-052-02-S. $24.00 each, plus shipping & handling.	Cylinder head gasket. Fits Kohler engine models MV16, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18, MV18, M20 and MV20. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. Click or tap here for cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below. High quality aftermarket. Replaces Kohler part # 52 041 20-S. $21.00 each, plus shipping & handling. OEM Kohler part # 52 041 20-S. $25.60 each, plus shipping & handling.
Cylinder head gasket. Fits Kohler engine models K482, K532 and K582. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. Cylinder head bolt torque values and sequences. Included in complete engine rebuild gasket set listed below. High quality aftermarket. Replaces discontinued Kohler part # 48 041 13-S. $25.00 each, plus shipping & handling.	Cylinder Head Gasket. Fits Kohler engine models K660 and K661. Torque head bolts to 15-20 ft. lb. / 180-240 in. lb. Approximately .050" compressed thickness. Doesn't need to be retorqued again once hot. New Old Stock. Discontinued Kohler part # 275156-S. $35.00± each (depending on source), plus shipping & handling. (When available.)
Crankshaft Oil Seals. Fits Kohler engine models K141, K160/K161, K181 and M8. Each included with complete engine rebuild gasket set listed below. IMPORTANT - Before installing any new oil seal, always apply oil or grease inside the seal and on the shaft to keep the rubber lubricated and cool until internal oil can reach it. With no prior lubrication, the dry rubber will wear away from friction, eventually causing another oil leak. Do the job right the first time, and it won't have to be done again for a long time. Flywheel End. High quality aftermarket. Dimensions: 1.250" I.D. x 1.500" O.D. Replaces discontinued Kohler part # X-583-1-S. $7.00 each, plus shipping & handling. PTO End. High quality aftermarket. Dimensions: 1.250" I.D. x 1.629" O.D. Replaces discontinued Kohler part # X-583-2-S. $9.50 each, plus shipping & handling. Crankshaft Oil Seal Installation Drivers/Tools for Kohler engine models K241, K301, K321, K341, K361, M10, M12, M14 and M16. Each installs flywheel end or PTO end oil seal to proper depth (1/8" below surface of housing hole) without damage. Use with medium size hammer. Fabricated by A-1 Miller's. Neither no longer available from Kohler. $25.00 each, plus shipping & handling. Crankshaft Oil Seals listed below. Fits Kohler engine models K241, K301, K321, K341, K361, M10, M12, M14 and M16. Each included with complete engine rebuild gasket set listed below. Shown with protective lubricating grease applied to inside of seal. IMPORTANT - Before installing any new oil seal, always apply oil or grease inside the seal and on the shaft to keep the rubber lubricated and cool until internal oil can reach it. With no prior lubrication, the dry rubber will wear away from friction, eventually causing another oil leak. Do the job right the first time, and it won't have to be done again for a long time. Oil Seal for Flywheel End. Dimensions of each seal below: 1.500" I.D. x 2" O.D. Each included with complete engine rebuild gasket set listed below. NOTE: Install seal 1/8" below surface of housing hole. High quality aftermarket. Replaces Kohler part # 47 032 06-S. $14.00 each, plus shipping & handling. OEM Kohler part # 47 032 06-S. $15.00 each, plus shipping & handling. Oil Seals for PTO End. Dimensions of each seal below: 1.500" I.D. x 2.378" O.D. x .308" Thickness. NOTE: Install seal 1/8" below surface of housing hole. High quality aftermarket. Replaces Kohler part # 47 032 07-S. $14.00 each, plus shipping & handling. OEM Kohler part # 47 032 07-S. $15.00 each, plus shipping & handling. High quality aftermarket. 1/2" thickness w/metal casing. Prevents seal on PTO end of K341, K361, M16, and open RPM competition pulling engines from being sucked into crankcase due to increased internal vacuum due to a larger piston and/or longer stroke, and at high RPM. To prevent an oil leak and to guarantee that seal will not eventually slip inward, apply liquid threadlocker on outside of seal and/or in housing hole before installing. Replaces discontinued Kohler part # X-379-9. $25.00 each, plus shipping & handling. Crankshaft Oil Seals. Fits Kohler KT-series and Magnum Opposed Twin Cylinder Engines. Each included with complete engine rebuild gasket set listed below. Shown with protective lubricating grease applied to inside seal. IMPORTANT - Before installing any new oil seal, always apply oil or grease inside the seal and on the shaft to keep the rubber lubricated and cool until internal oil can reach it. With no prior lubrication, the dry rubber will wear away from friction, eventually causing another oil leak. Do the job right the first time, and it won't have to be done again for a long time. Fits Flywheel End of Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. Also Fits PTO End of Kohler engine models MV16, MV18 and MV20. Dimensions: 1.370" I.D. x 1.780" O.D. High quality aftermarket. Replaces Kohler part # 52 032 10-S. $15.00 each, plus shipping & handling. OEM Kohler part # 52 032 10-S. $16.30 each, plus shipping & handling. Fits PTO End of Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18 and M20. Dimensions: 1.370" I.D. x 2.378" O.D. High quality aftermarket w/metal casing. To prevent an oil leak, apply clear RTV silicone adhesive sealant on the outside of seal or in the housing hole before installing. Replaces Kohler part # X-583-5-S. $10.00 each, plus shipping & handling. High quality aftermarket OEM-type w/rubber-coated metal casing. Replaces Kohler part # X-583-5-S. $15.00 each, plus shipping & handling. OEM Kohler part # X-583-5-S. $16.30 each, plus shipping & handling.
Flywheel End Crankshaft Oil Seal. Fits Kohler engine models K482, K532 and K582. Apply clear RTV silicone adhesive sealant on outside of seal or in housing hole before installing to prevent an oil leak. OEM Kohler part # 277065-S. $29.00 each, plus shipping & handling.	PTO End Crankshaft Oil Seal. Fits Kohler engine models K482, K532 and K582. Apply clear RTV silicone adhesive sealant on outside of seal or in housing hole before installing to prevent an oil leak. OEM Kohler part #'s 25 032 06-S, 52 032 08-S. $8.60 each, plus shipping & handling
Bearing Plate Shim Gaskets. Fits Kohler K-series engine models K141, K160/K161, K181, L160/L161, L181. Will also fit Kohler Magnum engine model M8 with clear RTV silicone adhesive sealant applied to seal up end of cam pin hole on flywheel end to prevent oil leak. Use various thicknesses of these to set the crankshaft clearance end-play at .002" (for low RPM engines) to .023" (for high RPM engines). Several of each included with complete engine rebuild gasket set listed further down in this website. .015" Thickness. OEM Kohler part # 230112-S. $4.95 each, plus shipping & handling. .030" Thickness. OEM Kohler part # 230071-S. $8.95 each, plus shipping & handling. Bearing Plate Shim Gaskets. Fits Kohler K-series engine models K241, K301, K321, K341 and K361. Will also fit Kohler Magnum engine models M10, M12, M14 and M16 with clear RTV silicone adhesive sealant applied to seal up end of cam pin hole on flywheel end to prevent oil leak. Use various thicknesses of these to set the crankshaft clearance end-play between .003" (for low RPM engines) to .020" (for high RPM engines). Several of each included with complete engine rebuild gasket sets listed further down in this website. .015" Thickness. OEM Kohler part # 235070-S. $5.90 each, plus shipping & handling. .030" Thickness. OEM Kohler part # 235757-S. $10.10 each, plus shipping & handling.
Oil Pan Gaskets. Fits Kohler engine models K141, K160/K161, K181, L160/L161, L181 and M8. Included in complete engine rebuild gasket set listed below. High quality aftermarket. $3.50 each, plus shipping & handling. OEM Kohler part # 41 041 03-S. $6.65 each, plus shipping & handling. Oil Pan Gaskets. .030" Thickness. Fits narrow base block Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361 with a narrow cast aluminum or cast iron oil pan, or if the block have been converted for use with a narrow base oil pan. Included in complete engine rebuild gasket set listed below. When ordering, please specify if you have a wide or narrow base block or oil pan. Click or tap here to determine if your engine is a wide or narrow base block. High quality aftermarket. $5.00 each, plus shipping & handling. OEM Kohler part # 235353-S. $7.65 each, plus shipping & handling. Oil Pan Gasket. .060" Thickness. Fits narrow base block Kohler K-series engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. To be used with a pressed steel sheet metal oil pan. Special use part; not included in complete engine rebuild gasket set. When ordering, please specify if you have a wide or narrow base block or oil pan. Click or tap here to determine if your engine is a wide or narrow base block. OEM Kohler part # 47 041 07-S. $16.60 each, plus shipping & handling. Oil Pan Gaskets. Fits wide base block Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361 with a wide base block. Included in complete engine rebuild gasket set listed below. Please specify if you have a wide or narrow base block or oil pan. Click or tap here to determine if your engine is a wide or narrow base block. High quality aftermarket. $3.50 each, plus shipping & handling. OEM Kohler part # 235057-S. $7.35 each, plus shipping & handling.
Complete Engine Rebuild Gasket Sets w/Oil Seals Listed Below [Return To Previous Paragraph, Section or Website]| [Top of Page]
Complete Engine Rebuild Gasket Sets w/oil seals. Fits Kohler engine models K141, K160/K161 and K181. NOTE: These gasket sets can also be used on the Kohler Magnum M8 engine by applying clear RTV silicone adhesive sealant where the cam pin hole is to prevent an oil leak. High quality aftermarket. Does not include crankcase breather filter. $24.00 each, plus shipping & handling. OEM Kohler part # 41 755 06-S. $88.00 each, plus shipping & handling.	Complete Engine Rebuild Gasket Sets w/oil seals. Fits Kohler engine models K241, K301 and K321. NOTE: These gasket sets can also be used on the Kohler Magnum M10, M12 and M14 engines by applying clear RTV silicone adhesive sealant where the flywheel end cam pin hole is to prevent an oil leak. High quality aftermarket. Does not include crankcase breather filter. Replaces Kohler part # 47 755 08-S. $32.50 each, plus shipping & handling. OEM Kohler part # 47 755 08-S. $118.70 each, plus shipping & handling.
Complete Engine Rebuild Gasket Sets w/oil seals. Fits Kohler engine model K341. NOTE: These gasket sets can also be used on the Kohler Magnum M16 engine by applying clear RTV silicone adhesive sealant where the flywheel end cam pin hole is to prevent an oil leak. High quality aftermarket. Does not include crankcase breather filter. Replaces Kohler part # 45 755 04-S. $36.50 each, plus shipping & handling. OEM Kohler part # 45 755 04-S. $97.65 each, plus shipping & handling.	Complete Engine Rebuild Gasket Set w/oil seals. Fits Kohler model K361 cast iron block single cylinder OHV engine. High quality aftermarket. Does not include crankcase breather filter. Replaces discontinued Kohler part # 45 755 06-S. $60.00 each, plus shipping & handling.
Complete Engine Rebuild Gasket Sets w/oil seals and valve stem seals. Fits Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. High quality aftermarket. Does not include crankcase breather filter. Replaces Kohler part # 25 755 37-S. $30.00 each, plus shipping & handling. OEM Kohler part # 25 755 37-S. $197.40 each, plus shipping & handling.	Complete Engine Rebuild Gasket Set w/oil seals. Fits Kohler engine models K482, K532 and K582. FYI: The gaskets and oil seals in this set will not fit Kohler engine models K660/K662. High quality aftermarket. Replaces discontinued Kohler part # 48 755 33-S. $40.00 each, plus shipping & handling.

"Popping" the Piston Out of the Cylinder -

"Popping" the piston out of the cylinder a few thousands of an inch by offsetting the bore in the connecting rod and installing bearing inserts, decking the block or using a custom piston and connecting rod combination will improve air flow and raise the compression ratio within the combustion chamber for more power and torque. Remember, when popping the piston out of the cylinder, there must a minimum of .030" clearance between the cylinder head and top of piston! To determine the distance between the cylinder head and piston, first measure the thickness of the compressed head gasket, and then subtract .030" for clearance. It may be necessary to machine the underneath area of the [billet] head directly over the piston to obtain the .030" safety clearance. Also, the edge of the piston must be ground away for improved combustion. See further below Ê.

If there's inadequate piston to cylinder head clearance, the piston will hit the head, without a doubt. If the engine is able to crank over and run, this will be evident by a loud tapping sound in the engine. A series of events will then soon happen: As the piston continues to strike the head, this will crush or flatten the soft metal coating (babbitt material) in the upper half of the bearing insert in the connecting rod, causing the rod to knock. But the knocking sound probably wouldn't be heard due to the piston hitting the head. Or there will be a "double knock." At very high RPM (wide open throttle), the looseness of the "flattened" bearing will cause the rod bolts to stretch. This will happen even in an aftermarket 4-bolt machined billet rod. But a stock OEM rod will probably just break. This could also cause the crankshaft to bend (or break), rather if it's made of cast iron or steel. If the engine is ran continually at open RPM, eventually the connecting rod will break, or the bolts in an aftermarket machined billet rod will break and the rod cap will become disconnected from the rod, which will likely destroy the engine block.

Being virtually all Kohler K241 and M10 pistons come within .020"± from the top of the block, which lowers the compression ratio. (The factory made them this way for reasons unknown.) I prefer to bore the K241 and M10 rods .020" offset so the piston will come flush with the top of the block. This will allow the engine to produce a little more power. It won't effect the longevity of the engine or cause any problems whatsoever. But sometimes with the .020" offset, the piston will pop out of the cylinder a few thousandths of an inch, which will still hurt nothing. And the bore can be offset .040" for a .020"± piston pop-out.

The OEM head gasket has a compressed thickness of about .050". The piston and cylinder head needs to have a minimum clearance of .030'. Therefore, with a milled head, the piston needs to pop out at a maximum of .020".

If you choose to use a piston and connecting rod combination that comes flush with the top of the cylinder, decking the block a maximum of .020" will allow the piston to pop out of the cylinder approximately .020". The stock head gasket is approximately .050" thick when compressed. Therefore, this will allow the .030" of the required clearance between the cylinder head and piston. In addition to decking the block, the valve seats will have to be re-done and proper valve lash adjustments must be made.

The compressed thickness of an OEM Kohler head gasket is about .050". The piston needs to have a minimum clearance of .030" due to rod stretch and crankshaft flex at very high RPM. And yes, when precision-balanced, even a cast iron crankshaft will flex a few thousands of an inch at open RPM without breaking.

The edge of the piston will have to be ground away with the piston in the block and connecting rod attached to the crankshaft. Otherwise, the edge may be too high or too low with the top of the engine block. And if the piston is going to be popped out just .020", there's no need to grind the edge away.

Removing Metal From the Edge of the Piston For Improved Combustion:

1. Place the crankshaft in the block along with the bearing plate.
2. With the rings off the piston, slide the piston, connecting rod with the bearing into the cylinder.
3. Rotate the crankshaft so the piston is at the top dead center (TDC) position.
4. Use a black felt tip ink marker to place a line on the side of the piston next to the deck which face the valves.
5. Remove the piston, and use a wide, flat belt- or disc-sander/grinder to grind an approximately 30º crescent-shaped angle on the top edge of the piston about 3/8" back at the widest area.
6. Finally, use fine sandpaper to smooth and polish the crescent-shaped edge.

Here's two interesting web sites: Arias Pistons (http://www.ariaspistons.com/) | J&E Pistons (http://www.jepistons.com/).

New high performance piston and ring sets are available from Lakota Racing (http://www.lakotaracing.com/), Midwest Super Cub (http://www.midwestsupercub.net/) and Vogel Manufacturing Co. (http://www.vogelmanufacturing.com/). They offer them in various sizes and compression heights. They also make billet connecting rods to match the compression height of the piston and stroke of the crankshaft.

The differences between the K241, M10, K301, M12, K321, M14, K341, M16 and K361 Kohler OEM pistons, rods and crankshafts:

• The K241 and M10 piston have a compression height of exactly 1.62". The wrist hole diameter is .8596" (minimum/worn) -.8599" (maximum/new). Length of the connecting rod when measured from the centerline of each hole is exactly 5.558" length. The crankshaft has a standard stroke of 2.875".
• The K301, M12, K321, M14, K341, M16 and K361 OEM piston have a compression height of exactly 1.7". The wrist hole diameter is .8757" (minimum/worn) - .8760" (maximum/new). Length of the connecting rod when measured from the centerline of each hole is exactly 5.3" length. The crankshaft has a standard stroke of 3.250".
• All the engines above È have the same deck height, which is exactly 8.625" (when measured from centerline of main radial ball bearings to top of block.)

What does "Compression Height" of a Piston Mean?

The compression height is the measured distance from the top of the piston to the center of the wrist pin. The stock K241 and M10 Kohler piston has a compression height of 1.62", and the stock 12 through 18hp Kohler pistons have a compression height of 1.7". When the wrist pin is located lower in the piston (this is known as "high compression height"), a shorter connecting rod must be used with the piston for it to come flush with the top of the engine block. The dome on a piston in an overhead valve engine is not considered as "piston pop-out." Only the flat area just above the top ring is measured for the piston compression height.

Many high performance pistons have the wrist pin located closer to the top of the piston. (This is known as "low compression height.") With a high performance piston with the wrist pin located closer to the top, a longer connecting rod must be used with the piston for it to come flush with the top of the block, or a slightly longer rod is used for the piston to pop out of the cylinder a few thousands of an inch. The reason many professional engine builders prefer to use a longer connecting rod is because they can pop the piston out of the cylinder, plus reduce the friction that the piston skirt places against the cylinder wall at very high RPM.

How to Calculate the Correct Piston Compression Height - This determines the crankshaft stroke, rod length and piston height combination for a competition pulling engine. Java Script will need to be enabled in your web browser for this to work. [Return To Previous Paragraph, Section or Website] [Top of Page]

Enter Deck Height: Measure from centerline of main bearings to top of engine block. (The deck height on Kohler K241, M10, K301, M12, K321, M14, K341, M16 and K361 blocks is 8.625".) Enter Crankshaft Stroke: (OEM Kohler K241 and M10 stroke is 2.875"; K301, M12, K321, M14, K341, M16 and K361 stroke is 3.25".) Enter Rod Length: Measure from centerline of wrist pin hole to centerline of crank journal (rod bearing) hole. (OEM Kohler K241 and M10 rods is 5.558"; and OEM Kohler K301, M12, K321, M14, K341, M16 and K361 rods is 5.3". NOTE: All OEM and aftermarket K241 and M10 rods measures 5.558", resulting in the piston being down in the cylinder approximately .015" at TDC. So for the piston to come flush with the top of the cylinder, the rod can be bored .020" offset toward the dipper with installation of bearing inserts, making it 5.578" in length. And for the K301, M12, K321, M14, K341, M16 and K361 rods, for a .020" piston pop-out, if it is bored .020" offset toward the dipper with installation of bearing inserts, this increases the rod's length by .020", making it 5.320" in length.) Enter Piston Compression Height: Measure from centerline of wrist pin to top of piston. (OEM Kohler K241 and M10 piston is 1.62"; K301, M12, K321, M14, K341, M16 and K361 pistons is 1.7".) Answer: = Piston Compression Height. This shows where the top of the piston is positioned in the cylinder at true 0º TDC. Definitions: 0 means piston comes flush (even) with top of cylinder/engine block [neutral piston height]; 0.xxx means amount of piston is down (submerged) in the cylinder/engine block [negative piston height]; and -0.xxx means amount of piston is protruding (upward) out of the cylinder/engine block [positive piston height].

Why Having Proper Crankshaft Clearance/End-Play Is So Important -

On virtually any engine, crankshaft clearance/end-play is a few thousands of an inch when the crankshaft can move side to side (horizontal shaft engines) or up and down (vertical shaft engines). Inadequate crankshaft clearance/end-play can have an effect on the crankshaft main radial ball bearings and engine performance.

Having proper crankshaft clearance/end-play controls the stability of the piston in the cylinder, lessens wrist pin wear, lessens ring wear and it lessens connecting rod bearing surface wear on the crank journal. On a vertical shaft engine, if the crankshaft has too much clearance/end-play, the piston will operate diagonally (at an angle) in the cylinder. This diagonal movement of the piston will cause the rings, wrist pin and rod bearing surface to wear unevenly and prematurely. But on a horizontal shaft engine, if the crank has too much clearance/end-play, the piston and connecting rod will wobble side to side in the cylinder (much like the clapper in a bell). at open RPM, the crankshaft can move back and forth so quickly, the wrist pin in the piston couldn't react quick enough to compensate for the excessive movement. Also, on engines such as the cast iron block Kohler with helical (angled) teeth on the crankshaft and camshaft gears, too much crankshaft clearance/end-play will effect the valve timing, which in turn will effect engine performance.

In a Kohler engine, insufficient crankshaft clearance/end-play will cause the main radial ball bearings to overheat and "tighten up" and produce a "whine" or "howling" sound at open RPM. The overheated bearings could also cause the engine to slow down for no apparent reason at open RPM when the [petroleum] motor oil reaches it's normal operating temperature.

Personally, I had a customer's K181 engine on a Troybilt garden tiller in my shop a few years ago that would run for about 20 minutes then die, apparently for no reason. Just like shutting off the ignition switch. It would crank over easy just after dying (recoil starter) and start right up, then die again after running for about 20 minutes. So after I replaced the spark plug, points, condenser, coil, installed a NOVA 2 module, cleaned the carburetor, performed a valve job, test ran the engine after performing each repair, it would still run great for about 20 minutes then die. So I figured the problem must be inside the engine. So I removed the engine from the tiller, and removed the oil pan, then I measured the crankshaft clearance/end-play and found it had insufficient clearance. After adding a shim gasket to the bearing plate so the crankshaft will have the correct clearance/end-play, I reassembled the engine, reinstalled it on the tiller, started it up and it ran for about 45 minutes with no problems. Then I shut it off, started it up again, and it ran well for about another 45 minutes. The problem was fixed. I told my customer what the problem was, and he told A-1 Miller's he purchased the tiller new and it has ran great for about 15 years, then started to die unexpectedly recently. He said nobody has ever worked on the engine either. He said the engine made no "whining" or "howling" sound either, that's associated with binding ball bearing main bearings. Why the "dying problem" didn't show up just after the tiller was purchased new, is probably because the engine block and/or crankshaft warped slightly from normal operating heat and the block shrunk or the crankshaft expanded a few thousandths of an inch which caused the crankshaft to bind in the main bearings when the engine reached its normal operating temperature when the metal is hot. So if you have an engine like this, and you've done everything you can think of with the ignition, carburetor and valves, and the problem still occurs, then the problem is obviously inside the engine.

FYI - The Kohler or aftermarket 8 ball roller bearings have larger diameter balls than the aftermarket 12 ball roller bearings, that have smaller balls. Therefore, the balls in the 8 ball bearings rotate slower, causing less friction. They run freer and more cooler. In theory, it seems that the 12 ball bearings would work better in an open throttle pulling engine, but in reality, it's a different story. Just like the factory-built Chevy V8 engines , Kohler engineers knew what they were doing when they designed the internal parts for their engines.

The bearing plate gaskets on a Kohler engine are also shims to set the crankshaft clearance/end-play. Although a dial indicator can be used, it's much easier and quicker to use a feeler gauge to accurately measure crankshaft clearance/end-play between the main bearings and the shoulders on the crankshaft where it butts against the bearing. Make sure the main bearings are fully seated in the bearing plate and engine block, too. If the crankshaft fits a little snug inside the bearings, and doesn't move side to side freely after installing the bearing plate with a .005" and a .010" gasket and after the bolts have been torqued to specs, use a 2 lb. brass hammer to gently drive the crank one way or the other to check the clearance/end-play. If the clearance/end-play needs to be corrected, remove the bearing plate and add or remove a .005" or a .010" gasket until the proper clearance/end-play is acquired. It may take several different thickness of gaskets to achieve the proper crankshaft clearance/end-play. This may be time consuming, but it must be done for the engine to run correctly. And due to the bearing plate being separated a few thousandths of an inch from the crankcase between the bolts, it'll be a good idea to apply clear RTV silicone adhesive sealant on the gaskets, to prevent a possible, messy oily film on the outside of the block. Also, with the bearing on the PTO end fully seated and the crankshaft is more or less butted against the bearing, and proper clearance/end-play on the camshaft, the [OEM cast] cam timing will be in perfect alignment with the piston.

To set the clearance, install one or two thick (.030") and/or one or two thin (.015") gaskets between the crankcase and bearing plate until the desired clearance is obtained. The clearance/end-play on the 10-16hp flatheads and the 18hp OHV Kohler single cylinder engines is .003" (for very low RPM engines) to .020" (for very high RPM engines). Personally, I like to set the crankshaft clearance/end-play anywhere between .012"-.020". We don't like the "closeness" of the .003"-.011" of clearance. The engines I build seems to turn freer at high RPM with the little more clearance.

Why Do Some Main Radial Ball Bearings Fit Tight on a Kohler Crankshaft and Others Have a Slip-Fit?

I've had new aftermarket and OEM Kohler main bearings fit on the crankshaft and in the bearing plate all kinds of ways. We had them slide on the crankshaft easy, and I had to use a big hammer to install them on the crankshaft. Then some of them have a slip-fit in the bearing plate, and I had to use a big hammer to drive the bearing plate onto the main bearing to install it against the engine block. But I've never had to actually use my hydraulic press to install or remove a main bearing from a crankshaft.

I've rebuilt many cast iron block Kohler engines through the years, and it seems that with all of them, either the crankshaft main journals were machined a few thousands of an inch different, or the main radial ball bearings were machined different. Either way, with some engines, when installing the crankshaft, I have to drive the crank into the bearing on the PTO side and sometimes I have to drive the bearing plate on, too. But with other engines, the crank just slides into each bearing. Being a machinist, I know that cast iron and steel contracts a few thousands of an inch in cool temperatures and expands a few thousands of an inch in warm temperatures. With this fact, being that Kohler's old manufacturing building(s) probably wasn't insulated that well or at all, it would seem that Kohler machined (ground) some of their crankshafts (and/or bearings) on a cool day during the winter months and others were machined on a warm day during the summer months. This would explain why there's a few thousands of an inch difference with the main journals on their crankshafts. The Kohler engine blocks and camshafts were probably milled or machined the same way. This is why the camshaft and crankshaft need shimming to acquire the proper clearance/end-play. If they were all machined exactly the same under controlled conditions, such as with CNC machines, the parts would all measure exactly the same and no shimming would be required. Either that, or the parts were machined on an early Monday morning, or late Friday afternoon.

Back in the day when Kohler machined their cast iron engine blocks, camshafts and crankshafts, quality control wasn't strict as it is today with the high precision of CNC machines. The same is true with the Cub Cadet garden tractor cast iron case transaxles, shafts and gears. This is why Kohler's camshaft and crankshaft require shimming (steel shims or various thicknesses of gaskets) to set the clearance/end-plays. Also, the ring and pinion gear teeth require [steel] shims to set the clearance and back-lash, and the tapered bearings need to be shimmed to set the preload. And as long as they're not bent or distorted, the shims can be reused with no problems. Nowadays, thanks to the precision of CNC machining, virtually all makes and models of engine blocks and transaxles don't require shims. for anything! As a matter of fact, many of them don't even use or require gaskets. They use clear RTV silicone adhesive sealant instead (except for the head gasket(s) on the engines).

It's common knowledge that most metals retracts (shrinks) a few thousandths of an inch when cool or cold, and expends (swells) a few thousandths of an inch when warm or hot. Knowing this, when building or rebuilding an engine, keep in mind that if the engine parts are either cool or warm, the clearance/end-plays for the camshaft, crankshaft, valves, piston-to-cylinder wall, etc., will vary according to the temperature conditions the engine is being assembled under. According to the manufacturer's clearance specifications, allow for slightly greater clearances if the temperature is cool (when working in a shop that don't hold heat well during wintertime), and for lesser clearances if the weather is around 72° F. Actually, it's best to build or rebuild an engine during warm weather with the engine parts warmed at room temperature around 72° F.

If all the oil were cleaned from the Kohler crankshaft main [ball] bearings with cleaning solvent and allowed to thoroughly dry, and then if the bearings were spun by hand, and if the bearings isn't worn much or at all, they will make a rattling sound. The noise isn't necessarily because the bearing is worn, the noise is caused by the balls running dry on the races (metal to metal contact) because there's no oil to separate the two. Apply a small amount of motor oil to the balls/races and then spin the bearings by hand. They should be a lot quieter now. The same thing will happen with new bearings. And if the bearings have very little free play in them (about .005"), like they're worn, don't worry about this. As the engine RPM increases and when the motor oil warms up, the balls in the bearings will expand. Even new bearings have little play in them for this reason. If all bearings, new or used, had no free play, as they get warm up, the balls would bind in the races, lessening the performance of the bearing.

Information About Using the Correct Connecting Rod for the Job -

If you've ever wondered about the differences between the early K-series connecting rods and the new style [Kohler Magnum engine] rods, the sides of the wrist pin hole on the new style rod are machined narrow so it can fit inside the new style (Magnum) Mahle forged piston. A new style rod will fit both the older K-series pistons and Mahle pistons without modification, but the K-series rod will fit only the K-series cast pistons. If you want to use a K-series rod with a Mahle piston, the sides of the wrist pin must be ground narrow so it'll fit inside the Mahle piston.

The best OEM connecting rod to hold up well above 4,000 RPM for use in a 12, 14 and 16hp engine is the one made for Kohler's 18hp OHV (K361) engine. The 18hp rods are much stronger than the 16hp (K341) rod, and more expensive. These rods should hold up well as long as the piston assembly and rod are precision balanced to the crankshaft's counterweights. Because no rod is indestructible when it comes to high speed out-of-balance rotating parts.

Advertisement: | Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

NOTE: All parts listed here are NEW, unless otherwise stated. We do not sell cheap junk! As a matter of fact, most OEM Kohler parts are made in China now. Kohler owns some of the factories in China that make the parts. And most aftermarket parts are also made by Kohler in China. Kohler just place the part(s) in a generic box and sell them for less money. So when purchasing a genuine OEM Kohler part that comes in a box with the Kohler name on it, you're really just paying more money for the name. And as far as some parts being no longer available - either the parts didn't sell well or the EPA is trying to phase out parts for the old cast iron block flathead engines because they produce more air pollution than the newer OHV engines.

There's "match marks" on both the rod and rod cap. They MUST be aligned or "matched up" so the big end of the rod forms a perfect circle around the crank journal when installed. Otherwise, if the cap is installed backwards, the "perfect circle" will be egg-shaped or oblong, which will bind on the crank journal. DO NOT over-tighten the rod bolts! Upon installation, the oil hole in the cap faces toward the camshaft. And if the threads strip out in a rod, then perhaps a longer grade 8 fine thread bolt can be installed in reverse (the rod will need to be machined for head bolt clearance) and use a grade 8 nut. If not, then the rod is scrap metal.

Connecting rods for Kohler engine models K90/K91. NOTE: Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is started for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD size for .938" diameter crank journal. New Old Stock. OEM Kohler part # B-220111-S. (Has numbers 220489 embossed on rod.) $57.00 each, plus shipping & handling. (When available.) .010" undersize for .928" diameter crank journal. This rod is made .010" undersize and not machined or resized to .010" undersize. OEM Kohler part # B-220111-10-S. $69.00 each, plus shipping & handling.

New Connecting Rods. Fits Kohler engine models K141, K160/K161 and L160/L161. These are plain aluminum bearing surface rods. Replaceable bearing inserts are not available for these particular rods. NOTE: Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is started for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD size for 1.1875" diameter crank journal. High quality aftermarket. $46.00 each, plus shipping & handling. OEM Kohler part # B-230039-S and John Deere part # AM31071. $103.70 each, plus shipping & handling. .010" undersize for 1.1775" diameter crank journal. The rods listed below are made .010" undersize and not machined or resized to .010" undersize. Crank journal must be reground .010" undersize to match this rod. High quality aftermarket. $46.00 each, plus shipping & handling. OEM Kohler part # B-230039-10-S. $78.10 each, plus shipping & handling.

New Connecting Rods. Fits Kohler K-series and Magnum engine models K181, L181 and M8. These are plain aluminum bearing surface rods. Replaceable bearing inserts are not available for these particular rods. NOTE: Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is started for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD size for 1.1875" diameter crank journal. For "old style" K-series cast piston with wide wrist pin hole. High quality aftermarket. Replaces Kohler part # 41 067 10-S. $37.00 each, plus shipping & handling. OEM Kohler part # 41 067 10-S and John Deere part # AM31062. $66.10 each, plus shipping & handling. .010" undersize for 1.1775" diameter crank journal. The rods listed below are made .010" undersize and not machined or resized to .010" undersize. For "old style" K-series cast piston with wide wrist pin hole. High quality aftermarket. Replaces Kohler part # 41 067 11-S. $44.00 each, plus shipping & handling. OEM Kohler part # 41 067 11-S and John Deere part # AM103292. $84.30 each, plus shipping & handling. For "new style" (Magnum) Mahle forged piston with wide wrist pin hole. (Strong rods.) STD size for 1.1875" diameter crank journal. OEM Kohler part # 41 067 08-S. $91.20 each, plus shipping & handling. .010" undersize for 1.1775" diameter crank journal. This rod is made .010" undersize and not machined or resized to .010" undersize. OEM Kohler part # 41 067 09-S. $91.20 each, plus shipping & handling.

New Connecting Rods. Fits Kohler K-series and Magnum engine models K241 and M10. Strong rods. Comes with long dipper. 5.558" length. NOTE: These rods can be bored for installation of bearing inserts, and crank journal must be reground to match diameter of undersize bearing inserts. Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. Bearing inserts cannot be used. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is started for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. A-1 Miller's Professional Repair Service - Bore YOUR Kohler scored or burnt connecting rod(s) and install replaceable lead-coated STD size, .010", .020", .030" undersize bearing inserts for a matching reground undersize crank journal. No need to purchase a new undersize rod. $65.00 for labor and bearing inserts, plus return shipping. A-1 Miller's professional crankshaft rod journal regrinding service also available. STD size for 1.500" diameter crank journal. High quality aftermarket. Replaces Kohler part # 47 067 13-S and John Deere part # AM103546. Has long integrated dipper for deep oil pan; cut half off for narrow, flat bottom oil pan. $44.00 each, plus shipping & handling. OEM Kohler part # 47 067 11-S. Has short integrated dipper for narrow, flat bottom oil pan. $130.40 each, plus shipping & handling. .010" undersize for 1.490" diameter crank journal. (Has hole drilled through beam section.) High quality aftermarket. This rod is made .010" undersize and not machined or resized to .010" undersize. Has long integrated dipper for deep oil pan; cut half off for narrow, flat bottom oil pan. Crank journal must be reground .010" undersize to match this rod. Replaces discontinued Kohler part # 47 067 12-S and John Deere part # AM37715. $48.00 each, plus shipping & handling. .020" undersize for 1.480" diameter crank journal. This rod is made .020" undersize and not machined or resized to .020" undersize. Has long integrated dipper for deep oil pan; cut half off for narrow, flat bottom oil pan. Crank journal must be reground .020" undersize to match this rod. Irrelevant Kohler or John Deere part numbers. $50.00 each, plus shipping & handling.

New Connecting Rods. Fits Kohler K-series and Magnum engine models K301, M12, K321 and M14. Comes with long dipper. 5.3" length. NOTE: These rods can be bored for installation of bearing inserts, and crank journal must be reground to match diameter of undersize bearing inserts. Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. Bearing inserts cannot be used. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is ran for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. A-1 Miller's Professional Repair Service - Bore YOUR Kohler scored or burnt connecting rod(s) and install replaceable lead-coated STD size, .010", .020", .030" undersize bearing inserts for a matching reground undersize crank journal. No need to purchase a new undersize rod. $65.00 for labor and bearing inserts, plus return shipping. A-1 Miller's professional crankshaft rod journal regrinding service also available. STD size for 1.500" diameter crank journal. High quality aftermarket. For "old style" K-series cast piston with wide wrist pin hole. Replaces discontinued Kohler part # 47 067 09-S and John Deere part # AM106441. $48.00 each, plus shipping & handling. High quality aftermarket. Same as above except has narrow wrist pin hole for "new style" (Magnum) Mahle forged piston. $58.00 each, plus shipping & handling. K-series and Magnum "New Style" connecting rod. This particular forged rod has a beefier and thicker beam section, which makes it just as durable as a machined billet rod, and with bearing inserts installed, it's suitable for open RPM engine operation. Discontinued OEM Kohler part # 45 067 24-S and John Deere part # AM106441. NOS (New Old Stock). $126.00 each, plus shipping & handling. (When available.) .010" undersize for 1.490" diameter crank journal. (Has hole drilled through beam section.) The rods listed below are made .010" undersize and not machined or resized to .010" undersize. Crank journal must be reground .010" undersize to match these rods. High quality aftermarket. For "old style" K-series cast piston with wide wrist pin hole. Replaces discontinued Kohler part # 47 067 10-S. $48.00 each, plus shipping & handling. High quality aftermarket. Same as above except has narrow wrist pin hole for "new style" (Magnum) Mahle forged piston. $58.00 each, plus shipping & handling. K-series and Magnum "New Style" connecting rod. This particular forged rod has a beefier and thicker beam section, which makes it just as durable as a machined billet rod, and with bearing inserts installed, it's suitable for high RPM and wide open throttle engine operation. OEM Kohler part # 45 067 25-S and John Deere part # AM106832. $204.80 each, plus shipping & handling. .020" undersize for 1.480" diameter crank journal. The rods listed below is made .020" undersize and not machined or resized to .020" undersize. Irrelevant Kohler or John Deere part numbers. High quality aftermarket. For "old style" K-series cast piston with wide wrist pin hole. $50.00 each, plus shipping & handling. High quality aftermarket. Same as above except has narrow wrist pin hole for "new style" (Magnum) Mahle forged piston. $65.00 each, plus shipping & handling.

New Connecting Rods. Fits Kohler K-series and Magnum engine models K341 and M16. These rods have a narrow wrist pin hole. Comes with long dipper. 5.3" length. NOTE: All 16hp rods, K-series or Magnum, have a narrow wrist pin hole. Also, these rods can be bored for installation of STD size, .010", .020",or .030" undersize bearing inserts, and crank journal must be reground to match diameter of undersize bearing inserts. Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. Bearing inserts cannot be used. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is ran for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. A-1 Miller's Professional Repair Service - Bore YOUR Kohler scored or burnt connecting rod(s) and install replaceable lead-coated STD size, .010", .020", .030" undersize bearing inserts for a matching reground undersize crank journal. No need to purchase a new undersize rod. $65.00 for labor and bearing inserts, plus return shipping. A-1 Miller's professional crankshaft rod journal regrinding service also available. STD size for 1.500" diameter crank journal. High quality aftermarket K-series rod. Replaces discontinued Kohler part # 45 067 22-S and John Deere part # 102766. $58.00 each, plus shipping & handling. K-series and Magnum "new style" rod. This particular forged rod has a thicker beam section, which makes it just as durable as a machined billet rod, and with bearing inserts installed, it's suitable for high RPM and wide open throttle engine operation. And when used with a factory type piston with a thin-wall wrist pin, the rotating assembly will not need to be rebalanced. OEM Kohler part # 45 067 24-S and John Deere part # AM106441. $124.50 each, plus shipping & handling. Return To Previous Paragraph È .010" undersize for 1.490" diameter crank journal. (Has hole drilled through beam section.) The rods listed below are made .010" undersize and not machined or resized to .010" undersize. Crank journal must be reground .010" undersize to match these rods. High quality aftermarket K-series rod. Replaces discontinued Kohler part # 45 067 23-S and John Deere part # AM102767. $58.00 each, plus shipping & handling. K-series and Magnum "new style" rod. This particular forged rod has a thicker beam section, which makes it just as durable as a machined billet rod, and with bearing inserts installed, it's suitable for high RPM and wide open throttle engine operation. And when used with a factory type piston, the rotating assembly will not need to be rebalanced. OEM Kohler part # 45 067 25-S and John Deere part # AM6632. $173.85 each, plus shipping & handling. .020" undersize for 1.480" diameter crank journal. This rod is made .020" undersize and not machined or resized to .020" undersize. Irrelevant Kohler or John Deere part numbers. $65.00 each, plus shipping & handling.

ALCOA Connecting Rods. Designed for Kohler engine model K361, but will fit Kohler engine models K301, M12, K321, d M14, K341 and M16 flathead engines. Extremely strong rods. These rods have a narrow wrist pin hole for the Mahle, K341 and K361 pistons. Comes with long dipper. 5.3" length. NOTE: These rods can be bored for installation of bearing inserts, and crank journal must be reground to match diameter of undersize bearing inserts. Crank journal must be reground .010" undersize to match this rod. The alternative to using an undersize rod is if a STD size or .010" undersize rod is in good condition, if the matching-size crank journal isn't deeply scored and/or badly burnt, it can be reground until it's perfectly round again and then if the original rod also isn't deeply scored and/or badly burnt, it can be resized to fit to odd-size undersize journal with the factory recommended .0025" oil clearance. Bearing inserts cannot be used. NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. IMPORTANT: To prevent scoring of the rod when the engine is started for the first time, apply automotive chassis grease or wheel bearing grease on crank journal before installing rod. This will better protect the parts until crankcase oil reaches them. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. A-1 Miller's Professional Repair Service - Bore YOUR Kohler scored or burnt connecting rod(s) and install replaceable lead-coated STD size, .010", .020", .030" undersize bearing inserts for a matching reground undersize crank journal. No need to purchase a new undersize rod. $65.00 for labor and bearing inserts, plus return shipping. A-1 Miller's professional crankshaft rod journal regrinding service also available. STD size for 1.500" diameter crank journal. Discontinued Kohler part # 45 067 15-S. NOS (New Old Stock). Price depends on source and availability. .010" undersize for 1.490" diameter crank journal. (Has hole drilled through beam section.) Crank journal must be reground .010" undersize to match this rod. Discontinued Kohler part # 45 067 17-S. NOS (New Old Stock). Price depends on source and availability.

New Connecting Rods. Fits Kohler engine models MV16, KT17 (first design), KT17 Series II, M18, MV18. Wrist pin hole diameter is .625". Bearing inserts are not available for these rods. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. STD size rod. Fits 1.3733"-1.3738" diameter crank journal. High quality aftermarket. $50.00 each, plus shipping & handling. OEM Kohler part # 52 067 67-S. $119.70 each, plus shipping & handling. .010" undersize rod. Fits 1.3633"-1.3638" diameter crank journal. The rods listed below are made .010" undersize and not machined or resized to .010" undersize. Crank journal must be reground .010" undersize to match this rod. High quality aftermarket. $50.00 each, plus shipping & handling. OEM Kohler part # 52 067 68-S. $150.00 each, plus shipping & handling. .020" undersize rod. Fits 1.3533"-1.3538" diameter crank journal. The rods listed below are made .020" undersize and not machined or resized to .020" undersize. Crank journals must be reground .020" undersize to match this rod. High quality aftermarket. $75.00 each, plus shipping & handling. New Connecting Rods. Fits Kohler engine models KT19 Series II, M20 and MV20. Wrist pin hole diameter is .750". The rods listed below will not fit the KT19 (first design) engine, and the KT19 (first design) rods are no longer available from any source. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. A-1 Miller's Professional Repair Service - Bore YOUR Kohler scored or burnt connecting rod(s) and install replaceable lead-coated STD size, .010", .020", .030" undersize bearing inserts for a matching reground undersize crank journal. No need to purchase a new undersize rod. $65.00 for labor and bearing inserts, plus return shipping. A-1 Miller's professional crankshaft rod journal regrinding service also available. STD size rod. Fits 1.4993"-1.4998" diameter crank journal. High quality aftermarket. Replaces discontinued Kohler part # 52 067 71-S. $75.00 each, plus shipping & handling. .010" undersize rod. Fits 1.4893"-1.4898" diameter crank journal. This rod is made .010" undersize and not machined or resized to .010" undersize. Crank journal must be reground .010" undersize to match this rod. High quality aftermarket. Replaces discontinued Kohler part # 52 067 72-S. $75.00 each, plus shipping & handling. .020" undersize rod. Fits 1.4793"-1.4798" diameter crank journal. This rod is made .020" undersize and not machined or resized to .020" undersize. Crank journals must be reground .020" undersize to match this rod. High quality aftermarket. $75.00 each, plus shipping & handling.

High Quality Bearing Inserts for Connecting Rods. Can be used in Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16, K361, KT19 Series II, M20 and MV20. Available in STD size, .010", .020", .030" and borable/resizable .060" (limited supply) undersizes. NOTE: Rod must be bored-out (and notched) to make room for bearing inserts. And a rod with a burnt aluminum surface can be bored-out and bearing inserts can be installed. Click here to learn how bearing inserts protect an engine. Rods for the before mentioned engines can be bored and notched to accept bearing inserts. Even severely burnt, scored, or rods with a mismatched cap can be bored for installation of bearing inserts. Only USA-made Clevite 77, Federal Mogul or Sealed Power bearing inserts will be installed. No low quality Chinese-made bearing inserts ever installed. All A-1 Miller's Professional Machined connecting rods include ground-out notches to prevent bearing rotation in rod and drilled oil hole for proper lubrication. Please indicate diameter of crank journal for size of bearing inserts. (STD size, .010", .020", .030" or resizable .060" undersizes.) Also, rods can be center-bored for top of piston to come flush with deck, or bored .020" offset for a .020"± piston pop-out at no extra charge. [Return To Previous Paragraph, Web Site or Section] Clevite 77 CB278 or CB2279, Federal Mogul 9885CP or 9885CPA, or Sealed Power Bearing Inserts. Please indicate size and tang offset. $25.00 each, plus shipping & handling. Bore and notch your rod only (customer supply and install own bearing inserts): $40.00 labor, plus return shipping & handling. Bore and notch your rod and install our bearing inserts: $65.00 ($25.00 for bearing inserts + $40.00 labor to bore and notch rod), plus return shipping & handling. Purchase one of our high quality rods, bore and notch rod and install our bearing inserts: Price of rod $45 + $25.00 for bearing inserts + $40.00 labor to bore rod = $110.00 total, plus shipping & handling. Click or tap here for A-1 Miller's professional crankshaft rod journal regrinding service. NOTE: If a crank journal is worn beyond specs or badly scored/burnt,it will need to be reground to the next undersize to match the appropriate size bearing inserts. And if you wish to have A-1 Miller's to bore a rod for you, please let me know if you want the bearing insert centered in the bore of the rod (5.300" rod length; piston flush with top of block), offset .020" (5.320" rod length; safe to use with a milled OEM stock head and stock head gasket) or offset .060" (5.360" rod length; use with a non-milled OEM head and stock head gasket) to pop the piston out of the cylinder (see below Ê) to raise the compression and help improve air flow within the combustion chamber for more power and torque. The bearing inserts I install in Kohler 10-16hp flatheads and 18hp OHV K361 connecting rods can be used for general lawn and garden use, stock or high RPM competition pulling engines. The rod will need to be bored exactly 1.625" for proper bearing to journal oil clearance. NOTE: Being virtually all Kohler K241 and M10 pistons come within .020"± from the top of the block, which lowers the compression ratio. (The factory made them this way for reasons unknown.) I prefer to bore the K241 10hp rods .020" offset so the piston will come flush with the top of the block. This will allow the engine to produce a little more power. It won't effect the longevity of the engine or cause any problems whatsoever. But sometimes with the .020" offset, the piston will pop out of the cylinder a few thousandths of an inch, which will still hurt nothing. And the bore can be offset .040" for a .020"± piston pop-out. FYI - Before I machine a rod for installation of bearing inserts, I use a metal "plug" alignment tool that I fabricated to precisely align the big hole of the connecting rod with the centerline of the spindle in my milling machine. Then while the plug is in the rod, I firmly clamp the rod to the milling machine table and after leaving the big hole centered or moving the table so many thousandths of an inch offset for piston pop-out, I lock the table so it won't move in any direction while boring the rod. But for reasons unknown, sometimes the cutting tool will bore the hole in the rod slightly off-center toward one of the bolts or studs. When this happens, I simply grind a small notch on the outside of each bearing shell so they'll clear the rod bolt. I've talked to other machinists who bore Kohler rods also about this and they tell A-1 Miller's sometimes the same thing happens to their rods. But as long as the outside of the bearing shells are notched for clearance of the bolt or stud, the off-center of the bearing inserts poses no problems whatsoever. And bearing inserts for the 10-16hp Kohler engines can be installed in Kohler models K482, K532 and K582 STD size connecting rods, but the crank journals would need to be reground exactly to 1.500" to match the inside diameter of the bearing inserts when installed in the rods. And for your information, STD size crank journals for the K482, K532 and K582 engines measures 1.6245".

Front Camshaft Bushing. Fits Kohler engine model K582. New Old Stock. Discontinued OEM Kohler part # 48 158 03-S. $26.00 each, plus shipping & handling. (When available.)

Crankshaft Main Bearings (Flanged Sleeve Bushings). Fits Kohler opposed twin cylinder engine models MV16, KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18 MV18, M20 and MV20. NOTE: With these engines, if one main journal is worn beyond specs (mostly likely the PTO end due to metal/dirt/debris contamination in the oil because of infrequent oil changes and/or lack of an oil filter), it can be reground undersize, and if the other main journal (most likely the flywheel end) measures within specs (1.742"), it can remain STD size. Remember - metal flake looks good in paint, not in oil. [Return To Previous Paragraph, Web Site or Section] Used and in excellent, unworn condition. STD size. (1.7407") OEM Kohler part # 52 030 10-S. $40.00 each, plus shipping & handling. New. STD size. (1.7407") OEM Kohler part # 52 030 10-S. $95.80 each, plus shipping & handling. New. .010" undersize. (1.7307") OEM Kohler part # 52 030 11-S. $191.00 each, plus shipping & handling. New. .020" undersize. (1.7207") OEM Kohler part # 52 030 12-S. $191.00 each, plus shipping & handling.

High Quality 8 Ball Main Crankshaft Radial Bearings. Fits Kohler K-series and Magnum cast iron block engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. Heat treated chrome steel (AISI 52100) for higher resistance and durability. Supports up to 17,000 RPM. Works excellent for general lawn and garden engines or for high performance competition pulling engines that run at open RPM. FYI - The 8 ball roller bearings have larger diameter balls than the aftermarket 12 ball roller bearings, that have smaller balls. Therefore, the balls in the 8 ball bearings rotate slower, causing less friction. They run freer and more cooler. In theory, it seems that the 12 ball bearings would work better in an open throttle pulling engine, but in reality, it's a different story. Dimensions: 1.57" (40mm) I.D. x 3.54" O.D. (90mm) x .90" (23mm) width. See note below Ê. NOTE: If your bearing(s) have more than .005" of play due to wear, or it feels rough or "rubbles" when rotated by hand with motor oil applied, then it should be replaced. FYI - All US and import manufacturers of ball bearings have always been made them to the metric dimensions. Where applicable, the manufacturers try to make them close as possible to the inch dimensions. [Return To Previous Paragraph, Web Site or Section] Used and in excellent condition. OEM Kohler bearing with very little to no wear. OEM Kohler part # 235376-S. $5.00 each, plus shipping & handling. (When available.) New high quality aftermarket. A-1 Miller's part #150973. Replaces Kohler part # 235376-S. $22.00 each, plus shipping & handling. New. OEM Kohler part # 235376-S. $116.55 each, plus shipping & handling.

To identify this particular type of rod, they look a lot like Kohler's K301, M12, K321, M14 and 16hp OEM rods, but they're of a very bright aluminum color. The word "ALCOA" and the numbers "45 564 01" (which isn't the correct part number) are embossed on the beam section. If you're planning to use one of these rods in a 12, 14 or 16hp engine, just remember that the crankshaft doesn't need to be rebalanced for use with it because it weighs the same as the other OEM rods. But do have it fitted with bearing inserts. But if you'd like to have them balanced anyway, it might help the engine run somewhat smoother. Return È

Most "part numbers" on Kohler connecting rods are meaningless. It seems that they're just random numbers that Kohler put on their rods. Why they did this, I have no idea.

The second best OEM Kohler connecting rod to will hold up to 6,000+ RPM in the 12, 14 and 16hp engines are the ones made for Kohler's 12, 14 and 16hp flathead Magnum engines. This particular forged rod has a thicker beam section, which makes it just as durable as a machined billet rod, and with bearing inserts installed and when the crankshaft is dynamically and precision spin-balanced, it's suitable for high RPM and wide open throttle engine operation.

Most .010" undersize rods have a small hole drilled through the beam section. If a standard size rod is used with an undersized crank journal, the engine will make a loud knocking sound at operating speeds and eventually rod failure will result. So be sure the rod is matched to the crank journal with proper oil clearance. And it's highly doubtful that a two-color rod (light gray at the wrist pin and dark gray at the crank pin) will hold up in a engine running at wide open throttle without a governor. But they seem to hold up very well with no problems in ordinary governed engines running at 4,000 RPM. By the way - any connecting rod that's going to be operated above 4,000 RPM should be fitted with bearing inserts. Also, if an OEM or Kohler-type rod is used, rebalancing of the crankshaft to the rod/piston isn't necessary. Aftermarket or high performance (heavier than stock) rods MUST be balanced to the crankshaft's counterweights. If an engine isn't balanced for use with an aftermarket rod, the engine will vibrate severely and eventually self-destruct. Click or tap here for flywheel and/or crankshaft balancing.

Torque the 10hp through 18hp connecting rod having the 3/8-24 bolts to 285 in. lb. or 24 ft. lb., and torque the studs w/nuts to 260 in. lb. or 22 ft. lb. For the cast iron block 7hp and 8hp engines, torque the rod bolts to 200 in. lb. or 17 ft. lb. DO NOT OVER TORQUE! And with the match marks aligned on the connecting rod and the cap, the rod goes in the cylinder with the oil hole in the cap facing toward the camshaft.

Repairing Stripped Threads in an Aluminum Connecting Rod -

If 3/8" threads in an aluminum rod become stripped due to over-tightening of the bolt or stud/nut, it can be repaired with a hardened 10-1.25mm fine thread metric bolt the same length as the OEM bolt. To make this happen, use a Letter S, 11/32" or 8.9mm drill bit to bore-out the stripped threads, then use a 10-1.25mm tap to cut new threads. Also, drill the bolt hole in the cap to 10mm. Use a flanged-head bolt or a split lock washer, to keep the bolt from loosening when torqued to specs. But if 5/16" threads become stripped in a rod, being there's no 9mm bolts available, a 5/16" grade 8, fine thread bolt about 1/2" longer than the original bolt could be used. To make this happen, drill out the stripped threads in the rod the same diameter of the bolt, then ground away about half of the bolt head so it will clear the beam section when it's inserted in the rod. A little grinding on the rod may be required so the bolt won't cause the rod/cap to bind on the crank journal when the nut is torqued to specs. Be sure to use a hardened serrated flange hex nut, too. And the additional weight of a slightly larger or longer bolt or bolts will not cause the engine to vibrate that much more, if at all.

If a Kohler (or aftermarket) connecting rod have bolts (not studs w/flared nuts) with a flat washer under the head bolts, replace them with grade 8 steel (dark or brass color) split lock washers of the appropriate size (either 5/16" or 3/8", depending on bolt size). After installing the rod in the engine, torque the bolts with the split lock washer to specs. The split lock washers will guarantee that the bolts will not loosen over time. This is especially important in an engine that runs at wide open throttle. But the flared OEM connecting rod nuts (w/studs) will not loosen when properly torqued to specs.

There's "match marks" on both the rod and rod cap. They MUST be aligned so the big end of the rod forms a perfect circle around the crank journal when installed. Otherwise, if the cap is installed in reverse, the "perfect circle" will be egg-shaped or oblong, which will bind on the crank journal. And DO NOT over-tighten the rod bolts, or the rod and cap will become distorted. If this happens, the rod will need to be honed back to the proper dimensions in a connecting rod honing machine. And the oil hole in the cap faces toward the camshaft.

Be aware - as with any engine running above 4,000 RPM, there is no guarantee that an OEM "one color" rod will not break. A "one color" rod only lessens the chances of it breaking. Actually, it's best to use a custom-made billet connecting rod and have the piston assembly and connecting rod precision balanced to the crankshaft's counterweights. Click or tap here to learn about precision flywheel and/or crankshaft balancing.

When a Connecting Rod Breaks or When an Engine "Throws a Rod" -

When the connecting rod breaks in an engine (due to either lack of crankcase oil or too high RPM), if you're lucky, no damage will be done to anything inside the crankcase except for a burnt crank journal and of course, a broken connecting rod. But if you're not lucky, the things to look for will be...

• After removing the oil pan, look at the bottom of the cylinder wall to see if there's a big chunk missing. If there is, the cylinder can be sleeved, or if installation of a sleeve is cost-prohibited, another [matching] engine block will need to be acquired. A small chunk doesn't matter as long as the skirt on the piston will be stable in the cylinder at Bottom Dead Center (BDC).
• Check the camshaft to see if it's broke in two. If the cam is bent, being it's made of cast iron, it's cracked and it'll break in two when tapped with a hammer. Also, check if there's a crack on the outside of the block where the cam pin goes into on the flywheel side. If there is a crack (due to the bent or broken cam), it can be welded up and the hole will need to be bored-aligned to match the centerline of the hole in the PTO side. This is to prevent slight bending of the pin, which would cause binding upon the installation of another cam.
• Look at the starter side of the block for a crack in the crankcase. If there's a crack, it can be welded up. But if there's a hole in the side of the block, and if you'll lucky enough to find the missing broke-out pieces, they may be welded back in the block. The same goes if the engine has a flat bottom oil pan.
• Remove the flywheel and see if the keyway is cracked. If it is cracked, it will need to be machined and/or replaced. Do not attempt to weld the crack or repair the flywheel in any way! It must not be reused because it will run out-of-balance. There will be danger of it splitting in two or exploding at high RPM, which could cause serious injury or death.

Installing bearing inserts in a rod for a Kohler engine would cost much less than purchasing a new or even used rod and/or crankshaft, even when used for non-pulling applications. Bearing inserts can be installed in new or used rods. They can also be installed in rods that's scored, have a heavily burnt surface (the burnt material/surface will need to be bored out anyway to make room for the bearing), or even if the rod has a mismatched cap! If installing a mismatched cap, align the match marks on the rod with the cap properly torqued to the rod, and use a wide, flat belt- or disc-sander/grinder to ensure proper fit and side clearance of the connecting rod on the crank journal.

By the way - As business is booming, we've reground MANY Kohler crankshafts to .020" and .030" undersize and installed bearing inserts in connecting rods and I have never had any problems with the crankshaft breaking, even when used in competition pulling when the engine turns at 6,000+ RPM. So it's a safe thing to do. Besides, I wouldn't have mentioned it here if it didn't work.

WHEN REBUILDING AN ENGINE, NEVER, EVER INSTALL A CONNECTING ROD DRY! Always lubricate the cylinder wall, piston rings, piston pin, bearing surface and crank journal thoroughly with oil or grease before installing! Failure to do so could (or more likely, will) result in prematurely worn rings, piston, rod journal damage or seizure, crank journal damage, a noisy and/or smoky engine and possible engine block damage!

Ever Wondered Why There's Longer-Than-Stock Length Custom-Made (Billet) Connecting Rods? (Updated 4/15/21)

The reason many high performance engine builders prefer to use a longer billet connecting rod is because there's less pressure from the piston skirt placed against the cylinder wall during higher RPM. At higher RPM or at wide open throttle, a longer-than-stock rod moves or "swings" side to side with less force, while a stock-length rod moves or "swings" more rapidly. Longer rods operate at less of an angle than shorter stock rods do. Therefore, piston skirt "drag" or scraping and force against the cylinder wall is greatly reduced and an engine will produce more RPM with less friction resulting in more horsepower and torque. In order for an engine to accommodate a longer rod, a special made light-weight piston with its wrist pin located closer toward the top (wrist pin location is known as "compression height") must be used. Many high performance engine builders prefer to pop the piston out of the cylinder a few thousands of an inch to help increase compression. To do this, either a stock OEM rod is bored offset for installation of bearing inserts, or a longer machined billet rod (that's made for bearing inserts) and custom piston combination is used.

Because billet connecting rods are much wider than OEM connecting rods, each lower side of the cylinder wall must be ground away for clearance of the rod. An easy (and proven) way to make this happen is with a 4" hand-held angle disc grinder. The support/side handle will need to be removed (unthreaded) from the grinder to access inside the crankcase for easier grinding of the cylinder wall. Or the sides of the cylinder wall could be machined-out in a milling machine. The minimum clearance between the rod and cylinder wall is .050" at full swing. The easiest way to check the clearance is with a piece of .050" thickness baling wire. The clearance is measured with the crankshaft in the block and piston (without the rings) fastened on the rod with the bearing inserts installed.

The bolts in billet connecting rods should be torqued to 18 to 20 ft. lb. Overtorquing them could result in distortion of the big end of the rod, making the hole for the bearing inserts slightly oblong or egg-shaped, which would cause the bearing inserts to bind or fit too tight on the crank journal when the bolts are torqued to specs. A 3/8" drive, 12 point 5/16" socket machined thin in a metal lathe is required for easy access to remove and install the special 12 point head bolts in Midwest Super Cub's and Vogel's billet connecting rods.

Being virtually all billet connecting rods have a short [steel] oil dipper, it's best to use a flat bottom [narrow base] cast iron oil pan with the crankcase oil filled to the full mark on the dipstick for sufficient lubrication of the internal parts of the engine. But if a deep sump cast iron oil pan is used, make sure the crankcase oil is always filled to the full mark on the dipstick. And the reason billet connecting rods have a short dipper is due to harmonic engine vibration at wide open throttle operation. On a single cylinder Kohler engine, engine vibration and harmonics happen at higher RPM regardless of how well the rotating assembly is balanced. Anyway, if the machined billet rod had a longer dipper, the harmonic vibration could cause the threads on the dipper to loosen or wallow-out in the connecting rod, resulting in the dipper eventually dislodging from the rod. This is also why the threads on the dipper are secured in the rod with high strength liquid threadlocker (Red Loctite or Permatex). If an OEM Kohler "new style" connecting rod is used in a competition pulling engine that runs at wide open throttle, due to harmonic vibration, it'll be a good idea to cut half of the oil dipper off.

When used in a high RPM application, aluminum connecting rods develop "rod stretch" over time, which could lead to rod failure. Even if it's a custom-made one. So to be safe, measure a used rod against a new or a known good one, or replace it after several years of use. And the connecting rod in ordinary lawn and garden engines will outlast the rod in high performance engines because there's less strain on them at 3,600 RPM. Also, at wide open throttle, in the 10-16hp Kohler engines, sometimes harmonics from normal engine vibration will cause the full-length oil dipper to break off when used with a deep-sump oil pan, resulting in insufficient lubrication of the internal engine parts, which will cause connecting rod failure. To prevent the possibly of this happening, cut half of the dipper off, and use a [cast iron] narrow, flat bottom oil pan instead. Being the dipper is short, engine vibration will not allow the dipper to break off.

And if you've ever wondered about this: the bolts and studs w/nuts in Kohler connecting rods are made of extremely hard material and can be reused over and over. They're very durable. Besides, nobody makes replacement bolts or studs for Kohler rods.

When installing the connecting rod and piston assembly in your engine, it's very important that the hole in the rod cap face the camshaft for proper lubrication of the rod journal. If it's installed facing away from the cam, the rod could burn. Also, both the connecting rod and cap are machined to form a perfect circle around the crank journal. So make sure that you install the connecting rod in the right way because both the rod and cap must be matched for proper fit around the crank journal.

A knocking, rattling, loud tapping, scraping or "weird" sound coming from an engine can occur in several different places. Here are the most likely causes:

1. Worn connecting rod and/or crankshaft rod journal will make a constant knocking sound. To check for a loose rod and/or worn journal, with the piston halfway in the cylinder, very gently rotate the flywheel (or crankshaft) back and forth by hand. If the rod/journal is worn, you'll feel it. You can feel when the piston comes up on the compression stroke by the resistance of the flywheel when rotating it. This is when it compresses air. And there'll be no resistance when the piston reaches TDC. So before or after it reaches TDC, this is when you can check for looseness of the rod on the crank journal. It's best to have the crank journal and connecting rod (although the journal will wear more than the rod) mic'd at a reputable automotive machine shop to determine the amount of wear.
2. Loose fitting piston in the cylinder will make an erratic rattling sound. To check for a worn beyond specifications or loose piston, with the cylinder head removed and the piston positioned at top dead center (TDC) on the compression stroke (when both valves are fully closed), forcibly move the piston from side to side by hand (with your thumbs). If the piston has a lot of play, you'll hear a rattling sound.
3. Too much crankshaft clearance/end-play will make an erratic rattling sound. To check this, wedge a flat-blade screwdriver between the bearing plate and flywheel and while pushing on the PTO end of the crankshaft with your hand, forcibly move the crankshaft back and forth. If there's too much clearance/end-play, you'll see it and hear it.
4. Worn balance gear bearings will make an erratic rattling sound. To check this, first remove the oil pan, and then move the balance gears side to side by hand. They may not make any noise when moving them by hand, but if they're excessively loose, they will make noise with the engine running. These can be removed without removing the crankshaft or rod/piston. With them removed, the engine will not vibrate any more than before. A heavy duty, angled-shaped, expandable snap ring pliers is required to remove the snap rings that holds the balance gears in place. Be sure to remove the thrust washers and spacers (if present), too. Leave the stub shafts intact. They will not interfere with anything.
5. Loose PTO pulley or electric clutch on the crankshaft may make an erratic knocking sound. To check these, with the engine not running, grasp the pulley or clutch by hand and forcibly move it/them back and forth. If there's too much play, you'll hear it.
6. A worn Cub Cadet garden tractor clutch disc will also make a knocking or rattling sound.
7. A loose flywheel will make a loud "clunking" sound when cranking the engine (with a gear starter) to start it. Once it starts, a loose flywheel may not make any noise.
8. A louder than usual tapping sound is caused by a valve with excessive stem-to-lifter clearance. (This is why solid lifters are called "tappets.") On rare occasions, on the 10-16hp flatheads and 18hp OHV engine, one of the adjusters in the lifter will back-off, causing a loud tapping sound. When this happens, the adjuster end can be removed from the lifter body and "spread out" with a small cold chisel so it will fit tight in the lifter body. Or it can replaced with one from another lifter with a tight adjuster, or the entire lifter may need to be machined and/or replaced.
9. A constant scraping sound is caused by the flywheel, flywheel screen or starter ring gear making contact with the flywheel housing.

By the way - main radial ball bearings in a Kohler engine wear extremely little, if any at all, and don't require replacing. Although I have seen some that are obviously worn and needed to be replaced. And worn main radial ball bearings won't make a knocking sound. They'll make a rumbling or growling sound because the crankshaft and flywheel will be spinning out-of-balance and the engine will have a more than-usual-vibration.

Gaskets Versus Silicone Sealant - Which Works Better?

Being the area between the mounting bolts on most used (previously installed) thin metal covers or plates tend to warp or "flex" a few thousandths of an inch, this leaves an air gap for oil to seep out of. This is where clear RTV silicone adhesive sealant comes in handy. It fills in the gaps and when no gasket is used, silicone fills in the irregularities or imperfections between the two metals, creating a 100% leakproof seal. But if the part is new and never been installed before, no silicone is required on the part or with a gasket. To remove any warpage and restore flatness, if possible (depending on the shape of the part), use a large, flat file, or resurface it on a wide, flat belt- or disc-sander/grinder. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.

How to fix a vertical shaft aluminum block Briggs & Stratton engine when oil leaks under the cylinder and burns oil/smokes out the exhaust - (Updated 9/17/22)

The lower part of the cylinder on most Briggs & Stratton aluminum block flathead single cylinder 10-12hp vertical shaft engines and the #2 cylinder on the opposed twin cylinder vertical shaft engines tend to warp and draw inward due to heat from normal operation of the engine. The lower part of the cylinder that makes contact with the sump cover tends to "pull away" from the sump, creating an oil leak. This creates an air gap which allows outside air to be sucked into the crankcase upon every upward movement of the piston(s), then as the piston(s) travels downward, oil inside the crankcase blocks the opening (but some oil will seep out). This "reciprocating action" and constant buildup of excess air being drawn inside the crankcase will compress in the crankcase and eventually force the crankcase oil past the piston ring end gaps and cause the engine to burn oil and smoke out the exhaust. Well, to fix this...

1. Drain the oil from the engine.
2. Remove the engine from the tractor or equipment it's mounted in. (This is much easier performed on a platform work table.)
3. Place the engine upside-down on a sturdy work bench.
4. Remove the oil sump cover. You may see part of the original gasket under the cylinder on the engine block where it got "sucked into" the crankcase. This is where the cylinder is warped.
5. Thoroughly clean off the gasket material from the engine block and oil sump. Make sure none falls into the crankcase! Place a clean shop towel in the crankcase to catch any removed gasket material.
6. Install a new oil seal in the sump cover. (The old one will probably leak oil from the sump being removed and/or years of use.)
7. Apply a thin bead of clear RTV silicone adhesive sealant on the gasket surface of the engine block and oil sump, and slightly more silicone under the cylinder. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.
8. Install a new oil sump gasket on the engine block.
9. Thoroughly lubricate the lower crankshaft main journal and camshaft stub journal with clean motor oil to prevent damage to either journal due to a "dry startup" when reassembled.
10. Reinstall the sump cover and torque the mounting bolts to specs.
11. Reinstall the engine in the tractor or equipment.
12. For summertime use only, install the proper amount of SAE 30 weight high detergent motor oil. For wintertime use, use 10W30 motor oil.
13. If repaired correctly, the engine now shouldn't leak any oil between the cylinder and sump. But if it continues to burn oil and smoke out the exhaust, perhaps it needs new piston rings.

How to Remove and Install an Oil Seal - (Added 11/28/16) [Top of Page]

To replace a crankshaft oil seal in an engine that is completely disassembled and crankshaft removed, just simply use a flat blade screw and medium size hammer to drive the seal out from inside the engine block, oil sump or side cover. But with the engine completely assembled, sometimes a leaking oil seal can be difficult to remove, and a new seal can be more difficult to install. There are two proven ways to remove an oil seal in an engine. One is with an oil seal puller tool, which works like a pry bar. This type puller needs to be hammered into the inner part of the seal, then the seal can be removed by simply prying it out. But use caution not to scratch the crankshaft or damage seal's housing hole with this tool!

Another method to remove an oil seal is to use an automotive slide hammer dent puller tool with a sheet metal or drywall screw fastened or welded on the end of the puller shaft. A hole, smaller in diameter than the screw on the puller, will need to be drilled through the flat part of the oil seal. Then carefully thread the screw into the hole and use the slide hammer to gently pull the seal out of its housing hole.

Or instead of using the slide hammer dent puller tool as described above, thread a short sheet metal or drywall screw into the drilled hole in the seal, and use a mini nail puller pry bar to remove the seal from its housing hole.

Before installing the new oil seal, thoroughly clean the oil, dirt and debris from the housing hole, and as an option, apply medium strength liquid threadlocker (Blue Loctite or Permatex) on the edge of the seal and in the housing hole so the seal will be secured in place. Use tubing the same size as the seal and medium size hammer to carefully drive the seal in the housing hole. FYI - When storing an opened container of liquid threadlock material or Super Glue, store it upright and not laying flat. The [capped] tip will not dry out and clog when stored upright. IMPORTANT - Before installing any new oil seal, always apply oil or grease inside the seal and on the shaft to keep the rubber lubricated and cool until internal oil can reach it. With no prior lubrication, the dry rubber will wear away from friction, eventually causing another oil leak. Do the job right the first time, and it won't have to be done again for a long time.

What Type of Motor Oil Should Be Used in Ordinary and High Performance Engines? [Return To Previous Paragraph, Web Site or Section]

First of all, full synthetic/organic or synthetic blend motor oils will allow an engine to run cooler and last longer than 100% conventional/petroleum motor oil. But the rule of thumb for different types of motor oils are: Full synthetic motor oil is beneficial for most air- or water-cooled for high performance/racing engines that operate at high RPM, or air- or water-cooled engines that operate under severe high temperatures (desert/tropical like areas) at normal speeds for a long time, such as most generator or water pump engines. Synthetic blend motor oil, which is a mixture of about 50% organic and 50% petroleum, is beneficial for air- or water-cooled engines that operate under moderate to high temperatures at normal speeds. And 100% conventional/petroleum motor oil is beneficial for air- or water-cooled engines that operate under moderate temperatures at normal speeds at all times, such as most lawn and garden engines. All of these oils can be used in a cast iron or aluminum block Kohler, Briggs & Stratton, Tecumseh and other small engine regardless if it has splash lubrication or an oil pump as long as the velocity (see below) is correct for the conditions the engine is operating under.

The Rule of Thumb for Various Motor Oils Are:

• Full synthetic motor oil is recommended for use in most modern day automotive engines with aluminum crankshaft bearings that operate under normal to severe (high revving) conditions.
• Synthetic blend motor oil is suitable for use in most older and modern day automotive engines with lead-coated or aluminum crankshaft bearings that operate under normal to moderate conditions.
• And 100% petroleum motor oil can be safely used in most older automotive engines with lead-coated crankshaft bearings that operate under normal conditions only.

Motor Oil Recommendations:

• SAE 30 100% petroleum is suitable for 40° F (5° C) and warmer temperatures. If used below 40° F, may cause slow cranking and delayed starting. SAE 30 motor oil is recommended for use in most lawn and garden small engines with solid lifters.
• 10W30 or 10W40 100% petroleum, synthetic blend or full synthetic oils is suitable for 0° to 100° F (-18° to 38° C) is better for varying temperature conditions. This grade of oil improves cold weather starting, but may increase oil consumption at 80° F (27° C) or higher. 10W30 or 10W40 motor oils are recommended for use in most older automotive engines, and 10W30 is required in Kohler Command lawn and garden engines, because these have hydraulic lifters (to prevent lifter chatter).
• 5W30 full synthetic is suitable for -20° to 120° F (-30° to 40° C). It provides the best protection at all temperatures as well as improved starting with less oil consumption.
• 5W30 is suitable for 40° F (5° C) and below for wintertime use, and works best in cold weather conditions.
• 20W50 is suitable for 32° F (5° C) and warmer temperatures. If used below 32° F, could cause slow cranking and delayed starting.

Motor oil technology have changed a lot since Kohler (and many other small engine manufacturers) published their oil recommendations 40+ years ago. In an older or freshly rebuilt air-cooled, lawn and garden engine with splash lubrication or if it has an unfiltered oiling system with no oil pump and/or no oil filter is used, it's best to use SAE 30 weight non-detergent motor oil. Non-detergent oil allow any impurities in the oil to settle to the bottom of the oil pan. Detergent oils suspends any impurities so the oil filter can better filter it. Detergent oils should be used only in engines with an oil filter. If an engine doesn't have an oil filter, it's best to use non-detergent oil for long engine life. If an engine is used during wintertime, and being there are no multi-weight or synthetic non-detergent oils available, the only option is the use 10W30 or 10W40 motor oils so the engine will crank over easy in cold weather to start fast. And be sure to change the oil when it's hot on a regular basis. Fresh oil is cheaper than an engine or engine rebuild.

Multi-Weight VS Straight Weight Oils -

During the hot summer months, it's best to use SAE straight 30 weight oil to better lubricate and help cool the internal moving parts of the engine and to prevent velocity oil breakdown. Being the Kohler K-series and Magnum single cylinder engines doesn't have an oil pump, which keeps a constant supply of oil to all moving parts, splash lubrication works differently. And it's harder to cool an air-cooled engine on a hot day. Automotive engines are liquid-cooled and they run a lot cooler. Therefore, they can make better use of multi-weight oils. Heavier SAE 30 oil doesn't thin out like multi-weight oils and it better separates the parts from having metal to metal contact, which cause premature wear. Actually, it's better to use full synthetic 10W30 or 10W40 oil in an air-cooled engine year-round. Full synthetic oil don't get near as hot as conventional petroleum oil. It maintains its velocity even during the hot, smothering summer days.

If you think about it, most pulling tractors don't run long enough (compared to race cars) to totally heat the oil and break it down so it's thin. But if it makes you feel any better, it's safe to use SAE 50 oil instead. Due to the extreme pressure of the internal moving parts at open RPM, don't use multi-weight oils such as 10W30 or 10W40. They could cause excessive wear, resulting in damage to internal parts.

But if you don't mind spending a few extra bucks, the best type of oil to use in a pulling tractor engine is full synthetic 10W40 motor oil. Dyno tests proved that an engine can gain 1 to 2 percent increase in horsepower using full synthetic oil. There's also less chance of full synthetic oil leaking because it doesn't "thin out" as easily as conventional petroleum oils, especially under extreme heat conditions. Because extreme heat has little or no effect on chemical-based products such as full synthetic oil, it doesn't break down due to extreme heat like petroleum-based oils sometimes do. Once you understand the properties of full synthetic oil vs conventional petroleum oil, you will never use conventional petroleum oil again. And either type of oil may need to be changed periodically if burning methanol fuel. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.

If an engine has a cooling system (air blowing over the cylinder's cooling fins by use of the flywheel fins or a 12 volt electric fan), then it'll be okay to use a high grade conventional petroleum oil. But if there's no cooling system whatsoever, it'll be better to use a full synthetic 10W40 motor oil.

Synthetic oil is mainly used in high-revving and high performance engines, in gearboxes and in differential units that operate at high RPM for long periods of time because full synthetic oil won't get hot like conventional petroleum oil does, which protects the internal moving parts better. But mineral oil, which is more commonly known as conventional petroleum oil, is used in ordinary engines that will never operate at extremely high RPM for long periods of time.

Here's a story I'd like to share: I talked to an older race car owner about the difference between conventional and full-synthetic oils. He told A-1 Miller's that back in the day when only conventional/petroleum motor and gear oils were available, when he raced on different tracks, sometimes his pit crew had to swap out the ring and pinion gears according to the length of the track. He said they had to wear heavy gloves to handle the gears due to the heat (from friction). But when he went to using full-synthetic gear oil, the gears were barely warm, and they could handle them with their bare hands.

Using a quality full synthetic oil will allow an engine to run cooler, operate smoother and last longer. The engine will rev up easier because there's less friction of moving and rotating internal parts. Conventional petroleum oils get hot (too hot to handle with bare hands) and their additives break down after a while, and if not changed regularly, sludge will form. Full synthetic oils never get hot. They stay cool to the touch the entire time the engine is running and their additives don't break down. Therefore, no sludge. It's really amazing how well full synthetic oils work. There's also a synthetic blend type of motor oil that's 30% synthetic and 60% petroleum. They don't offer the same protection that full synthetic oil do.

Full synthetic oils provide maximum protection, cooler operating temperatures, and longer engine life. No conventional petroleum oils can match the performance of full synthetic oils. Unlike conventional petroleum oils, full synthetic oils don't get hot. It stays the same temperature regardless of engine operating temperature. An older experienced race car mechanic once told A-1 Miller's on different length tracks, they have to swap out the ring and pinion gears to be competitive against other race cars. After running on the track in a race, when they changed the gears and when they used petroleum gear oil, they had to wear gloves to handle the hot gears. Then they switched to full synthetic gear oil, and after running on the track in a race, and when they changed out the gears, they didn't need to wear gloves because the gears and oil was as cool as the day they installed it. And synthetic oil blends helps provide engine protection, cooler operating temperatures, and longer engine life. Not as much as full synthetic, but it does help. Personally, I prefer Mobil 1 full synthetic motor oils because I've always had good results with them, heard good things about them from other mechanics. But then again, motor oil is a funny thing and some people will argue about which brand of oil works best. About all you can do is use your better judgment of which brand and type of oil to use and hope for the best, that your engine will last a long time. (By the way - As business is booming, wonder why there are so many different brands and types of motor oils available, yet there's only a handful of different brands of gear oils, automatic transmission fluids and power steering fluids available, and not to mention all the different oil additives!? )

FYI - Did you know that full synthetic oils will not burn when poured on an open fire pit? Some brands will smoke and some won't, but none of them will burn like conventional petroleum oils do.

Basic rule of thumb concerning the viscosity (thickness or thinness) of motor oil is this: Rub some between your finger tips. If it feels too thin, chances are it won't provide the needed protection for your engine.

Also, I think using oil additives to prolong the life of an engine don't do a thing. If oil refineries thought that an additive would help an engine last longer, they would put it in their oil. Additives is just something to get people's money, nothing more. What works best in an unfiltered engine (no oil pump/filter), is glue a small rare earth/neodymium magnet to the inside bottom of the oil pan or engine base to attract steel or cast iron metallic fragments for longer engine life. Because some of the ferrous metallic wear fragments settle to the bottom of the oil pan, engine block or gearbox and do not drain out with the oil when performing an oil change, even when the oil is hot. But make sure the oil dipper on the connecting rod doesn't make contact with the magnet! Remember - metal flake looks good in paint, not in oil.

IMPORTANT - Any engine with an oil dipper on the connecting rod that has splash lubrication or with an oil pump but without an oil filter will have metal particles in the oil. This is unavoidable and unpreventable. I've seen many fresh-built cast iron block Kohler engines after just a few minutes of run time have metal particles in the oil. This is just normal engine break-in or wear-in of parts that make contact with each other. If the metal particles are left in the oil for a long period, without an oil filter, this will cause the internal parts of the engine to wear, which will create more metal particles in the oil, and escalate into severe engine wear. This is why the oil in non-filtered engines needs to be changed more often than engines with an oil filter. The use of high quality detergent oil (with zinc) helps, too. Anyway, to separate the ferrous (steel/iron content) metal fragments from the oil, is place a strong magnet in the bottom of the oil pan/sump to attract the metallic fragments. This will help the engine last much longer. I think this is something that should be done with a Kohler, Briggs & Stratton, Tecumseh and other small engine that have splash lubrication. Remember - metal flake looks good in paint, not in oil.

FYI - If you've ever wondered where the terms engine "break-in" and when an engine is "broken-in" originated from, well, these are obviously derived from the days when most people depended on horses for their main transportation and hard work. The term "break-in" is when a wild horse is broke to be kind and gentle, and serve its master. "When you break a horse, it is broken in. When a horse is broken in, it's easy to care for, behaves better and provides better use for its strength and endurance to get the job done. And when an engine is "broke in", it too, better serves its owner for strength and endurance. Because nothing actually "breaks" inside an engine when it is "broken in." Just like the term "horsepower" originally came from the strength of horses. Think about it. This is the only explanation for these terms.

Do Not Use an Excessive Amount of "Oil Thickener" in an Engine! (A customer's experience that I like to share.)

I had a K321 Kohler engine in my shop in 2013 that burned a lot of oil. The owner told A-1 Miller's the engine was recently rebuilt by somebody else, but always smoked badly, so he filled the crankcase with a high viscosity motor oil treatment or additive, such as Motor Honey. He said after several hours of running, the engine started knocking and rattling badly, but the smoking lessened. The owner said he drained the oil before bringing the engine to me. He said it drained out like molasses! Anyway, he had A-1 Miller's rebuild the engine and I found the connecting rod had wore the crank journal, and the piston was also worn. I told him the oil dipper on the connecting rod must've cut a groove through the thick oil and couldn't splash it around sufficiently in the crankcase like [thinner] conventional (petroleum-based) motor oil does to keep the parts well-lubricated. (Upon inspection of the piston rings' orientation, I found that the previous engine builder installed the 2nd (middle) ring on the piston upside-down!)

And the gas/oil mixture ratios for 2-cycle or 2-stroke engines -

• In the early model 2-cycle engines, if the connecting rod and main journals have bronze bushings (no needle bearings), to prevent wearing of the rod and main bearings, these are supposed to have a 10:1 gas/oil mix. (Which will, without a doubt, cause it to smoke a lot out the exhaust at all times.)
• In later model 2-cycle engines, if the connecting rod have needle bearings, but the mains have bronze bushings, to prevent wearing of the main bearings, these are supposed to have a 16:1 gas/oil mix. (Which will cause it to smoke a little out the exhaust, especially under a load.)
• But for newer 2-cycle engines with needle bearings throughout, these are supposed to have a 32:1 - 40:1 gas/oil mix. (May not cause much smoke out the exhaust, except under a load.)
• And for all water-cooled 2-cycle outboard boat motors, to prevent burning of the piston skirt and/or possible engine seizure, a 50:1 gas/oil mix can be safely used. Because water-cooled 2-cycle engines operate much cooler than any air-cooled engine, especially on a hot day.
• FYI - Most manufacturers of 2-cycle chainsaws nowadays recommend the 50:1 gas/oil mix because they're in the business of selling new chainsaws. A fool and their money are soon parted. Don't be a fool! What the people don't know, but trust the manufacturer, makes the rich man richer. The manufacturers nowadays laugh all the way to the bank!

By the way - The only difference between 2-cycle oil and SAE 30 weight motor oil is the color. Being SAE 30 weight oil is basically the same color as gas, a dye is added to 2-cycle oils so you can see if oil have in fact been added to the gas. But if SAE 30 weight oil is added to the gas instead of 2-cycle oil, you can tell if oil is present in the gas by rubbing some of it between your fingers. If it feels slippery, oil have been added, but if it feels "dry" or "rough", no oil is mixed with the gas. [Return To Previous Paragraph, Web Site or Section]

About the Early Kohler Twin Cylinder Engine Models K482, K532 and K582 Governor Assembly Oil Lubrication System, Prior to Serial Number 9224060 -

One of the 1/8" NPT pressurized oil ports on the PTO end of the engine block can be used to lubricate the governor assembly. But the oil pressure going to the governor will need to be reduced so it won't take away a lot of pressure from lubricating the engine bearings. Kohler makes an oil line restrictor (Kohler part # 62 294 06-S) that does just this. The governor assembly doesn't require a lot of oil either. And if there's no way for the oil to drain back into the crankcase from the governor assembly, an oil return line may need to be installed from the governor assembly to the crankcase. Also, if the engine doesn't already have one, it'll be a good idea to install an oil pressure gauge.

Break-In (Wear-In) Oils and Procedure for Newly Rebuilt Lawn and Garden Engines -

For proper break-in (wear-in) of a new or fresh rebuilt engine, use a high quality conventional (petroleum-based) SAE 30 weight motor oil containing a high zinc content anti-wear additive, such as ZDDP (Zinc dithiophosphate), so the internal moving parts, especially flat tappet lifters and camshaft lobes, will get hot, create a wear pattern and produce a hardened surface. Run an engine with aluminum cylinder wall(s) normally (up to 3,600 RPM) for 2 hours, or for an engine with cast iron cylinder wall(s), run it normally (up to 3,600 RPM) for 5 hours. Don't be afraid to run a fresh-built or freshly rebuilt engine at full governed speed. Just run the engine as usually off and on for 2 or 5 hours to perform lawn and/or garden work as usual. Idle speed should be set at 1,200 RPM (±75 RPM) so the oil dipper can lubricate the internal moving parts more thoroughly. This speed also allows the flywheel fins to blow adequate amount of air across the cylinder head and around the cylinder fins to cool the engine better. Then drain the oil while it's hot. Be sure to tighten the oil drain plug securely after draining the oil. But don't tighten the plug too tight because the oil pan could crack or the threads could strip out. Anyway, either continue to use conventional (petroleum-based) SAE 30 oil, or switch to a quality 10W40 synthetic blend or full synthetic oil for warm weather use. Or use conventional (petroleum-based) 10W40 oil, or 10W40 synthetic blend or full synthetic 10W30 oil during cold winter use. Use no oil additives. Change the oil every 25 hours of engine run time or once a year. Full synthetic oil don't get as hot as conventional (petroleum-based) oil does. It's more slippery and remains cooler than conventional (petroleum-based) oil even after the engine has been in operation for several hours to better protect internal parts for longer engine life. Adhering a very strong rare earth/neodymium magnet to the bottom of the oil pan inside an engine to attract metallic wear fragments will also help an engine last longer. Because some of the ferrous metallic wear fragments settle to the bottom of the oil pan, engine block or gearbox and do not drain out with the oil when performing an oil change, even when the oil is hot. And does the Slick 50 Advanced Formula Engine Treatment really prevent engine wear with no oil in the crankcase? Well, watch this video: This Engine Runs WITHOUT OIL!! HOW?? (https://www.youtube.com/watch?v=x1hvx_UZLEI). Remember - metal flake looks good in paint, not in oil.

Break-In (Wear-In) Oils and Procedure for Newly Built/Rebuilt Pulling Engines -

For proper break-in (wear-in) of a rebuilt or fresh built pulling engine, use a high quality conventional (petroleum-based) SAE 30 weight motor oil containing a high zinc content anti-wear additive, such as ZDDP (Zinc dithiophosphate), which places a protective coating between all internal moving parts, will get hot, create a wear pattern and produce a hardened surface, especially flat tappet lifters and camshaft lobes. Don't be afraid to run a fresh-built or freshly rebuilt pulling engine at speeds it is designed for. Just run the engine normally for 4-5 pulls. Idle speed should be set at 1,200 RPM (±75 RPM) so the oil dipper can lubricate the internal moving parts more thoroughly. This speed also allows the flywheel fins to blow adequate amount of air across the cylinder head and around the cylinder fins to cool the engine better. Then drain the oil while it's hot, and either continue to use ordinary SAE 30 oil, or switch to a quality 20W50 synthetic blend or full synthetic oil. Use no oil additives. Change the oil every 25 pulls or once a year. Synthetic-blend oils get about half as hot as conventional oils. But full synthetic oils don't get near as hot as conventional oils do. It's more slippery and remains cooler even after the engine have been in operation for several hours to better protect internal parts for longer engine life. Adhering a very strong rare earth/neodymium magnet to the bottom of the oil pan inside an engine to attract metallic wear fragments will also help an engine last longer. Because some of the ferrous metal wear fragments settle to the bottom of the oil pan or engine block and do not drain out with the oil when performing an oil change, even when the oil is hot. Remember - metal flake looks good in paint, not in oil.

If the tractor is geared correctly, the pulling engines I build should not run out of power at the end of the pull. It should spin the tires. But there's some things that needs to be checked after a few pulls as the engine breaks-in and parts wear into each other. For gas fuels, the ignition timing needs to be set at 22° BTDC. And make sure the high speed fuel mixture screw is set so the engine runs smooth at high RPM. Also, if a high-output/performance ignition coil is used, it require two ordinary (Kohler) condensers or one high-capacity/performance condenser. This is so the coil will produce full voltage. And with a high-output/performance coil, the spark plug gap can be set at .060". With an ordinary coil, it should be set at .035". The valve to lifter clearances may need to be reset at .010" for the intake and .014" for the exhaust.

Furthermore, when a new or rebuilt engine needs to "break-in," what the term "break-in" actually means is the moving internal parts that make contact with each other needs to "wear-in" with each other so they'll produce a wear pattern and last longer. Any new or rebuilt engine, rather if it's for general lawn and garden use, snow removal or for competition pulling, needs to fully break-in (wear-in) for it to produce full power. Rings don't "seat," they break-in, or wear-in with the cylinder wall, and they wear-in quickly. But the valves are the parts that needs to "seat." Being the valve faces and seats have different angles (30°/31° or 45°/46°, respectively), the valve faces needs to wear into the seats to seal in the compression 100%. Wear-in will produce a 30½° or 45½° angle on both the matching valve face and seat. The harder material the valves are made of, the longer it takes for them to "seat" or wear-into the seats. Go here for more information: Valvoline.com > FAQs > Motor Oil Car FAQs > Racing Oil. Return To Previous Paragraph, Web Site or Section È

FYI - If you've ever wondered where the terms engine "break-in" and when an engine is "broken-in" originated from, well, these are obviously derived from the days when most people depended on horses for their main transportation and hard work. The term "break-in" is when a wild horse is broke to be kind and gentle, and serve its master. "When you break a horse, it is broken in. When a horse is broken in, it's easy to care for, behaves better and provides better use for its strength and endurance to get the job done. And when an engine is "broke in", it too, better serves its owner for strength and endurance. Because nothing actually "breaks" inside an engine when it is "broken in." Just like the term "horsepower" originally came from the strength of horses. Think about it. This is the only explanation for these terms.

What makes crankcase oil to have a black appearance after a while is caused by blow-by of the combustion process due to either: excessively wide gaps in worn piston rings; carburetor flooding; idle air/fuel mixture set too rich, resulting in engine running rich on fuel; or prolonged slow idling with a [high-performance] long duration camshaft. The excessive unburned/partially burned gas will seep past the piston ring end gaps and into the crankcase oil, contaminating and diluting it, eventually break down the protective additives in the oil, causing sludge, resulting in premature wear to internal moving parts. This is why it's so important to have a "fine tuned engine" and change the oil regularly. Remember - fresh, clean oil in an engine is cheaper than a new engine or engine rebuild!

Oil Refill Quantities for Older Kohler Engines - IMPORTANT: Make sure the correct oil dipstick is used and it's calibrated correctly! *NOTE: Add 1/8 quart for a competition pulling tractor with a lowered front-end that have a single cylinder longitudinal engine.

Engine Model(s)	Engine Model(s)	Engine Model(s)*	Engine Model(s)*	Engine Model(s)	Engine Model(s)	Engine Model(s)
K90/K91	K141, K160/K161, K181, L160/L161, L181 and M8	K241A, M10, K301A, M12, K321A, M14, K341A, M16	K241, M10, K301, M12, K321, M14, K341, M16, K361	KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, M18, M20	MV16, MV18, MV20	K482, K532, K582, K660/K662
3/4 Quart	1-1/4 Quarts (Full mark is 3/8" above oil pan gasket.)	1 Quart for engines with a flat bottom narrow base oil pan. 1-1/2 Quarts for engines with a deep sump narrow base oil pan. (Full mark is 3/8" above oil pan gasket.)	2 Quarts for engines with a wide base oil pan. (Full mark 3/8" above oil pan gasket.)	1 Quart without oil filter | 1-1/2 Quarts with oil filter.	1-1/4 Quarts without oil filter | 1-3/4 Quarts with oil filter.	3 Quarts | Add 1/2 quart for K482, K4532, K582 when replacing filter. Add 1 quart for K660/K662 when replacing filter.

If a small gas engine refuses to crank over, but is known to have the connecting rod intact and the piston moves freely in the cylinder, then either the starter motor is worn out or burned up, the battery voltage may be low, or if heavier-than-stock valve springs are used, the lever on the compression release mechanism could be broken. Or the ends of the tiny (hair-like) actuating spring on the compression release arms isn't connected. The compression release mechanism is an integrated part of the camshaft. It can't be replaced by itself. We wouldn't think it could be repaired either. So to replace the camshaft in any typical small engine on a lawn and garden tractor or garden tractor...

1. First drain the oil from the engine.
2. Remove the hood/grille from the tractor (they're easy to remove; this is much easier to do on a platform work table), remove the muffler, PTO pulley, electric clutch, wiring and fuel line from the engine.
3. Remove the engine from the equipment (this is much easier to do on a platform work table) and place it on a sturdy work bench or table.
4. Rotate the crankshaft so the piston is positioned exactly at top dead center (TDC) on the compression stroke. This is when both valves are fully closed. Remove the valve cover to observe the valve movement when the crankshaft is being rotated. Run a long screwdriver or thin rod through the spark plug hole to feel when the piston is at TDC.
5. Now position the engine upside-down and remove the bolts that secure the oil sump to the crankcase.
6. Remove the oil sump, and then the camshaft can be removed from the engine.
7. When installing a new (or good used) cam, be sure to align the match marks on both the cam gear teeth and crankshaft gear teeth! The crankshaft may need to be rotated for the marks to align.
8. Reassembly is opposite of disassembly.
9. Install a new sump cover gasket and the sump cover on the crankcase, and torque the bolts to specs.
10. With the piston at top dead center (TDC) on the compression stroke, adjust the valves to specs and install a new valve cover gasket.
11. Apply clear RTV silicone adhesive sealant on the gasket mating areas to lessen the chance of an oil leak. By the way - I've always preferred to use clear RTV silicone adhesive sealant for three reasons: Due to metal any warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities or imperfections between mating surfaces, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, a thin bead of silicone makes for a clean and professional-looking repair job. It can't be easily seen or noticed between the parts.
12. Install SAE 30 weight motor in the crankcase once the engine is reinstalled on the equipment.

Important Information About the Oil Dipstick -

If "piecing together" a 10-16hp cast iron block single cylinder Kohler engine from various parts off of other engines, remember, the oil dipstick and/or tube may not be the right one for a particular engine. According to the engine specification, Kohler made 23 different lengths and types of oil dipsticks. I've found several dipsticks and/or dipstick tubes that's not calibrated to various Kohler engines. Some are too short and some are too long. This includes the ones that mount on the side of the block, next to the gear starter, or on top of the crankcase, next to the cylinder, but not the one that mounts over the cam gear (cam gear cover dipstick).

If the dipstick is too long or the tube is too short, the engine won't have enough oil in the crankcase, which could eventually lead to disaster. And if the dipstick is too short or the tube is too long, the engine will have too much oil, which could blow out the crankcase breather atmospheric vent hole for engines that run at open RPM. Also, make sure that the "end cap" or "stop cap" is properly positioned on the dipstick. If it slipped out of position from normal wear, this will give an incorrect oil level reading, which the oil level will actually be too low. If it did slip, the cap will need to be realigned (calibrated) and tack-welded back in place.

To fix a loose fitting oil dipstick tube, remove the tube, and use something tapered or a flared socket to spread the end of the tube slightly. Then before reinstalling the tube, apply high strength liquid threadlocker (Red Loctite or Permatex) to permanently secure it in place in the aluminum holder. FYI - When storing an opened container of liquid threadlock material or Super Glue, store it upright and not laying flat. The [capped] tip will not dry out and clog when stored upright.

Checking the Accuracy or Correct Length of the Oil Dipstick -

For Kohler engine models K141, K160/K161, K181, L160/L161, L181 and M8, K241, M10, K301, M12, K321, M14, K361, M16 and K361, the engine crankcase is full with the oil level at 3/8" above the oil pan gasket. If in doubt about the accuracy of the oil dipstick, hold the dipstick on the outside of the block with the cap (on the dipstick) even with the top of the dipstick tube or the threads on the dipstick even with the top of the crankcase (where the crankcase meets the cylinder) and then see if the FULL mark on the dipstick is at 3/8" or 1/2" respectively, above the oil pan gasket. If it's not, then the correct length dipstick will need to be used with the engine, or an adjustment to the dipstick needs to be made to be calibrated correctly. This method removes all guesswork when the oil is full in the crankcase. And always fill an engine with oil to the FULL mark on the dipstick.

In rare cases, sometimes the oil dipstick isn't accurate or calibrated right from the factory. I've had engines in my shop where the factory spot weld on the top of the dipstick broke loose, and the dipstick went all the way to the bottom of the engine. When the owner filled his engine with oil and checked the level, he thought it was full of oil, but really had far less then required. (This caused an insufficient oil level, which resulted in the rod burn on the crankshaft.) And also, sometimes a dipstick will get lost or misplaced (sabotage of the lawn mower) or get broken, and replaced with a wrong length oil dipstick, which is not calibrated right like the original one. [Return To Previous Paragraph, Section or Website]

How to Prepare or Winterize an Engine and/or Equipment for Long-Term Storage -

1. First of all, prepare a cool, dry place of storage with low humidity to lessen the chance of condensation corrosion and rust.
2. Drain the entire fuel system from the equipment to be stored. This includes the carburetor float bowl, fuel pump, fuel line, fuel filter and fuel tank. Leave the hose(s) disconnected and if necessary, use 150± PSI compressed air with an air blow gun nozzle to clear out any remaining fuel from the system. The system must be totally dry. FYI- I think all fuel stabilizers are something just to get unsuspecting people's money. The best thing to do is drain the entire fuel system if the equipment isn't going to be used for a long period of time. Remember: "A fool and their money are soon parted."
3. If the engine is equipped with an electric or mechanical fuel pump, apply about a teaspoon-full of clean automatic transmission fluid in the pump so the rotor vanes will not stick or pump diaphragm will remain flexible and to prevent the poppet valves from sticking or becoming corroded. (Automatic transmission fluid contains rust inhibitors to prevent corrosion and rust.)
4. Remove the spark plug, squirt about a teaspoon-full of clean automatic transmission fluid into the combustion chamber.
5. Reinstall the spark plug and crank the engine several revolutions to evenly distribute the oil on the cylinder wall, valves, seats and valve stems/guides.
6. Run the piston at top dead center (TDC) on the compression stroke. Doing this will allow the valves to be fully closed and prevent them from sticking open, and the valve springs will be under less pressure.
7. If the equipment is equipped with a 12 volt battery, disconnect the positive post, and use a trickle charger to maintain the battery voltage, or better yet, remove the battery, store it in a warm environment and use a trickle charger to maintain the battery voltage.
8. If the engine is connected to a power/pressure washer, and if it's stored in a cold (unheated) environment, DEFINITELY clear the water out of the pump with 150± PSI compressed air with an air blow gun nozzle. Then install pure anti-freeze to mix with any remaining water in the pump to prevent from freezing. Failure to do this, if the air temperature drops below the freezing point (0º C or 32º F) could cause the [pure] water to freeze solid, expand and crack the pump's casing, ruining it. (A new pump would probably cost just as much or more than an entire pressure washer.)
9. Then store the engine/equipment in a cool, dry environment. Avoid storing it in a damp and high humility environment.
10. And that's all that's to it! When the engine/equipment is ready for reuse, pour fresh fuel in the tank, crank the engine and it should start right up with no problems! [Return To Previous Paragraph, Section or Website]

Removing the Variator from an Engine -

The variator (drive half of a torque converter pulley system) is threaded onto the crankshaft PTO end by right hand threads. We had an engine that needed rebuilding with this in my shop a few years ago and I had one heck of a time getting the variator off. What I did, after removing everything as much as I could from the engine block including the oil pan, and after reinstalling the bearing plate to stabilize the crankshaft so it wouldn't break, I placed the block in my 12 ton hydraulic press, and placed a wooden block under the counterweights of the crankshaft to keep the crank from rotating when I try to loosen the variator. We placed light pressure of the press on the block just to hold it in place. After applying Liquid Wrench, then eventually used my acetylene torch on the crankshaft/variator threads, I used a large open end wrench with a "cheater bar" (long pipe over the handle of the wrench) to apply extra downward leverage to remove (unthread) the variator. We remember I had to grind the wrench narrow so it would fit the hex nut on the variator between the block and variator. We had to purchase an [older] wrench off of eBay because I couldn't find one reasonably locally or elsewhere online. Anyway, when the variator came loose, it made a loud "bang" sound, the block and press shook, and I thought the crankshaft had broke, but it didn't. The variator was loose.

How to Remove a Broken-Off Exhaust Mounting Bolt or Stud and/or Rusted-In Exhaust Pipe Fitting, and Information about Exhaust Header Pipes [Top of Page]

First of all, as far as removing a broken-off bolt or stud for an exhaust flange is concerned, I have never had any luck with screw extractors. In my experience, all they do is thread itself deep into the drilled-out stud and expand the bolt/stud, making it harder to remove. So what I do is center-drill into the broken-off bolt/stud using a small bit as a pilot hole, then drill into the bolt/stud with the appropriate size drill bit, then I re-thread the hole with a TAPER hand tap of the appropriate size, then finish re-threading it with a PLUG tap.

If you've ever had an engine with a stubborn or rusted exhaust elbow pipe fitting that's threaded-in-the-block, then you probably already know how much of a pain it is to remove. Well, this is how to remove the fitting if enough of it is protruding from the end of exhaust port:

1. Apply penetrating oil to the pipe fitting threads and end of exhaust port. Gunk Liquid Wrench works great for this!
2. Firmly clamp the engine block in a hydraulic press or place it under a heavy vehicle. Do this only to secure the block in place so the fitting can be removed.
3. Use a large adjustable plumber's pipe wrench to remove the fitting. Rotate the fitting counterclockwise to loosen it. If the pipe wrench alone won't loosen it, slide a 3 foot± long steel tubing on the pipe wrench's handle for added leverage. And don't worry, the block shouldn't crack or break when loosening the fitting.
4. If the fitting breaks off flush with the block when attempting to loosen it, use a reciprocating saw with a metal cutting blade to cut through the threads of the fitting in the exhaust port (make several cuts in the fitting if necessary), and chisel out the remains of the fitting to collapse the threads. IMPORTANT: Chisel only where the metal is thick [around the exhaust port] to avoid breaking off part of the exhaust port!
5. After the entire fitting or the remains of the fitting is removed, if the threads inside the port are going to be used for another fitting, clean and straighten the threads with an NPT tap of the appropriate size. A replacement fitting can now be installed. Or, if the engine is going to be used for competition pulling, grind out the threads and install a professional header pipe with a bolt-on flange as shown below.

And the use of header pipe wrap will retain exhaust heat within the pipe and help the engine produce slightly more power and torque. But word of caution - header pipe wrap should only be used on galvanized-coated, aluminized, stainless or chrome-plated steel pipes. When used on a plain steel header pipe, the pipe will draw moisture as the engine cools and retain the moisture under the wrap while the tractor is in storage. The moisture may eventually cause the pipe to rust out. (A-1 Miller's header pipes are made of quality galvanized-coated steel.) Go here for a supplier of quality metals: Cold Rolled Steel Sheets and Coils Supplier - Majestic Steel USA.

Exhaust Manifold or Header Pipe Mounting Gaskets VS Silicone Sealant - Which Works Best?

Personally, whenever we install exhaust manifolds or header pipes on an engine, we don't use gaskets. Instead, we use clear RTV silicone adhesive sealant because silicone will not burn due to normal or extreme exhaust heat. Also, gaskets will compress or "squeeze down" where the fastening bolts are, causing the cast iron manifold to flex a few thousandths of an inch or thinner steel header flange to compress more than a few thousandths of an inch where the mounting bolts are. When metal is compressed, the uncompressed area that's between the bolts will allow the gasket(s) to leak and eventually burn out. Also, before we install the manifolds or headers on an engine, we use a long, wide flat file to make sure the mounting flanges on the manifolds or headers are perfectly flat. Using silicone and the elimination of gaskets will allow the manifolds or header flanges to be mounted flat against the cylinder heads, creating absolute metal-to-metal contact, which also keep the bolts securely tight. Plus, the silicone fills in the irregularities or imperfections between the two metals, eliminating any leaks. By the way - it's best to use Clear RTV Silicone Adhesive Sealant for three reasons: Gaskets don't always seal the irregularities between mating metals, especially thin metal covers; being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean and professional-looking repair job. When applied sparingly, it can't be easily seen or noticed between the parts. Also, engine heat has very little effect on silicone rubber. It can withstand up to 2,500 degrees heat.

Unsportsmanshiplike Conduct -

There's a cheater in every sport, and tractor pulling is no different. When at the pulls, to prevent a disgruntled puller from sabotaging a competitive pulling tractor by jamming a rock or piece of wood down the exhaust header pipe (this have been known to happen), and to "cap off" or plug the end of the header pipe to prevent rain water from entering the pipe, it's best to use an adjustable rubber expansion plug, like the one in the photo to the right ->. Most popular ones are: Dorman AutoGrade 02601 (1-1/4"), Dorman AutoGrade 02602 (1-3/8"), or Dorman AutoGrade 02603 (1-1/2"). These require an open or boxed-in 1/2" wrench the loosen and tighten the jam nut (to expand the rubber against the pipe), and these require more effort to remove [by a cheater] than a wingnut, or using the popular slip-on vinyl sleeve cover, because cheaters always prefer a quick and easy way to sabotage a competitor's tractor.

Advertisement: | Please contact A-1 Miller's if you're interested in purchasing any of the products or services listed in this website. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page] (Prices are subject to change without notice.)

Exhaust Port Gasket. Fits Kohler engine models K141, K160/K161 and K181 with 1-9/16" bolt hole spacing. OEM Kohler part # 231090-S. $4.80 each, plus shipping & handling. Exhaust Port Gasket. Fits Kohler engine models K141, K160/K161, K181 and M8 with 1-11/16" bolt hole spacing. OEM Kohler part # 41 041 01-S. $5.50 each, plus shipping & handling. Exhaust Port Gasket. Fits Kohler engine models K241, M10, K301, M12 and K321, M14. OEM Kohler part # 235122-S. $8.60 each, plus shipping & handling. Exhaust Port Gasket. Fits Kohler engine model K361. OEM Kohler part # 45 041 12-S. $5.50 each, plus shipping & handling. NOTE: Exhaust port gaskets for Kohler engine models K90/K91 (part # 220122-S), K341 and M16 (part # 45 041 15-S) are discontinued from Kohler. Use clear RTV silicone adhesive sealant instead. (Silicone sealant is heat-resistant, it will NOT burn out, even with extreme exhaust heat.)
Approximately 5/16" Thickness Steel Header Pipe Flange with 1-5/16" Center Hole. Fasten to block with two 5/16-18 UNC x 1" length Allen head bolts. Fits Kohler engine models K241, M10, K301, M12, K321, M14. NOTE: Two 5/16-18 UNC threads must be precision-aligned drilled and tapped (preferably with a Taper hand tap) 1-1/4" deep to fasten flange to block. How to Professionally Clean Out/Straighten Already Existing Threads or Cut New Threads. Use clear RTV silicone adhesive sealant instead of gasket. (Silicone sealant is heat-resistant, it will NOT burn out, even with extreme exhaust heat.) Exhaust flange with two Allen head mounting bolts. A-1 Miller's fabricated part. $10.00 each, plus return shipping & handling.	Approximately 1/4" Thickness Steel Header Pipe Flange with 1-1/2" Center Hole. Fasten to block with two 5/16-18 UNC x 1" length grade 8 hex head bolts (or Allen head bolts) and flat washers. Fits Kohler engine models K341 and M16. NOTE: Two 5/16-18 UNC threads must be precision-aligned drilled and tapped (preferably with a Taper hand tap) 1-1/4" deep to fasten flange to block. How to Professionally Clean Out/Straighten Already Existing Threads or Cut New Threads. Use clear RTV silicone adhesive sealant instead of gasket. (Silicone sealant is heat-resistant, it will NOT burn out, even with extreme exhaust heat.)Exhaust flange with two mounting bolts and flat washers. $20.00 each, plus return shipping & handling.
Bolt-On Header Pipe Kits. Fits Kohler Engine Models K241, M10, K301, M12, K321 and M14. For competition pulling engines with stock-size or oversize valves running at 4,000 RPM or at wide open throttle. High grade durable and galvanized-coated mild steel pipe resists rust and will not rust or discolor, even from exhaust heat. Has a 90º, 4" radius bend; each pipe extends 8" from exhaust port to midway of bend for plenty of hood clearance and measures 18" upward from midway of bend. Kit includes 1-5/16" O.D. x 1.260" I.D. x 24" overall length header pipe, 2-1/2" O.D. x 1-5/16" I.D. x 5/16"± thickness round mounting flange and two 5/16-18 UNC Allen head bolts. Flange fastens directly to engine block without a round mounting adapter and clamp, just like automotive engines with headers. No gasket required; use clear RTV silicone adhesive sealant instead. By the way - Silicone is heat-resistant, it will NOT burn out, even with extreme exhaust heat. FYI: When I have my 1-5/16" pipes bent at a local automotive muffler shop, being there is no 1-5/16" I.D. die to fit around the pipe, I use a 1-1/4" I. D. x 1-1/2" O.D. x 12" length steel tube, split in two, with one half cut in two, then I place them inside the 1-1/2" die. And sometimes while the pipe bends, this creates slight crinkles on the sides of the elbow, which will not interfere with the exhaust flow whatsoever. Click photos to the right for a larger view. 1-5/16" O.D. Header Pipe Only. (Customer supplies own flange.) $15.00 each, plus shipping & handling. Complete 1-5/16" O.D. Header Kit with Pipe Not Welded to Flange. (Customer welds pipe to flange.) $25.00 per kit, plus shipping & handling. Complete 1-5/16" O.D. Header Kit with Pipe Professionally Welded to Flange. $35.00 per kit, plus shipping & handling. Bolt-On Header Pipe Kits for Kohler Engine Models K341 and M16. For competition pulling engines with stock-size or oversize valves running at 4,000 RPM or at wide open throttle. High grade durable and galvanized-coated mild steel pipe resists rust and will not rust or discolor, even from exhaust heat. Has a 90º, 4" radius bend; each pipe extends 8" from exhaust port to midway of bend for plenty of hood clearance and measures 18" upward from midway of bend. Kit includes 1-1/2" O.D. x 1-3/8" I.D. x 30" overall length header pipe, 2-3/4" O.D. x 1-1/2" I.D. x 3/16"± thickness round mounting flange and two 5/16-18 UNC grade 8 hex head bolts. 1" length of pipe inserts inside exhaust port covering internal NPT threads for unrestricted airflow. Flange fastens directly to engine block without a round mounting adapter and clamp, just like automotive engines with headers. No gasket required; use clear RTV silicone adhesive sealant instead. (Silicone is heat-resistant, it will NOT burn out, even with extreme heat.) 1-1/2" O.D. Header Pipe Only. (Customer supplies own flange.) $15.00 each, plus shipping & handling. Complete 1-1/2" O.D. Header Kit with Pipe Not Welded to Flange. (Customer welds pipe to flange.) $25.00 per kit, plus shipping & handling. Complete 1-1/2" O.D. Header Kit with Pipe Professionally Welded to Flange. $35.00 per kit, plus shipping & handling. shipping & handling.
A-1 Miller's Machine Shop Service -Drill and tap two 5/16-18 UNC threaded holes on exhaust port of engine block to install custom bolt-on exhaust system or header pipe (listed below). Service is for Kohler engine models K141, K160/K161, K181, M8, K241, M10, K301, M12, K321, M14 or K341, M16. NOTE: For accuracy and precision of holes to be drilled, crankshaft and bearing plate must be removed from engine to fasten block in fabricated fixture on the table of milling machine. $75.00 labor, plus return shipping with FedEx Ground. A-1 Miller's Machine Shop Service - Remove or drill out broken exhaust bolt(s) and recut 5/16-18 UNC threads for installation of new bolts or studs in exhaust flange on engine block to install custom bolt-on exhaust system or header pipe (listed below). Service is for Kohler engine models K141, K160/K161, K181, M8, K241, M10, K301, M12, K321, M14, K341 or M16. NOTE: If broken bolt(s) needs to be drilled-out, for accuracy and precision of holes to be drilled, crankshaft and bearing plate must be removed from engine to fasten block in fabricated fixture on the table of milling machine. $20.00 - $50.00 labor (depending on difficulty of work involved), plus return shipping with FedEx Ground.
A-1 Miller's Machine Shop Service - Resurface exhaust flange on engine block to ensure 100% sealing of header mounting flange to prevent from loosening due to a heavily rusted, uneven, rough surface. NOTE: For accuracy, crankshaft and bearing plate must be removed from engine to fasten block in fabricated fixture on the table of milling machine. $50.00± labor, plus return shipping with FedEx Ground.	A-1 Miller's Machine Shop Service - Cut new threads in exhaust port when one of the fastener bolts or hand tap break off and is too hard to drill out. $50.00± labor each, plus return shipping & handling.

A-1 Miller's Professional Repair Service - Perform Valve Job Only on opposed twin cylinder Kohler KT-series and Magnum engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20. This service is for an engine that does not blow blue smoke out the exhaust and burn oil. Performing a professional valve job restores full compression, which allows the engine to start quicker, idle smoothly, rev up with no hesitation, produce lots of power, and run for a long time without stalling or dying (when the ignition timing and carburetor adjustments are set correctly, too). Labor includes: regrind four valve faces and seats, lap in valves with valve lapping compound, reset valve clearances to factory specifications (on short block only), resurface both cylinder heads on a wide, flat belt- or disc-sander/grinder to remove any warpage and restore flatness, reinstall intake manifold and governor linkage. And being some valve guides wear beyond specifications, there will be an extra charge for installing and reaming new guides, if needed. The baffle shields (sheet metal), muffler, intake manifold and governor linkage will need to be removed before bringing or shipping engine/short block to A-1 Miller's (new) shop. To save on shipping cost, only the cylinders (removed from the crankcase) and valves can be shipped in two 12-1/4" x 12-1/4" x 6" USPS Large Flat Rate Boxes. Place one box inside the other to double the strength, and use rigid packing material under, over and around/between the parts to prevent any of the fins from breaking off during shipment. But the short block must be shipped in a sturdy wooden crate. Prices listed below with your cylinder heads/jugs or engine on my work table. Please contact A-1 Miller's if you're interested in having a professional valve job performed on your KT17, KT17 Series II, KT19, KT19 Series II, KT21, MV16, M18, MV18, M20 and MV20 cylinder heads/jugs or engine.

• Perform Professional Valve Job on 2 Cylinders Only. (Customer resets valve clearances.) $70.00 labor, plus return shipping & handling.
• Perform Professional Valve Job and Reset Valve Clearances on Short Block (baffle shields (sheet metal), intake manifold and governor linkage removed). $200.00 labor, plus return shipping with FedEx Ground.
• If needed, install thin-wall bronze sleeves/liners in worn OEM valve guides. $20.00 each, plus return shipping. FYI - The alternative to installing new replacement OEM-type valve guide(s) is to have the old [worn] guide(s) reamed for installation of thin-wall bronze sleeves/liners (bushings), which can be installed by an experienced and reputable automotive machine shop. Thin-wall bronze valve guides are a low-cost and actually works better than replacing the OEM guide in most engines. Bronze lasts longer than cast iron guides because it is harder material and it retains more oil for better lubrication of the valve stem. Installing CLASSIC Bronze-Liners

A-1 Miller's Professional Valve Repair Service for Kohler Engine Model K361 Cylinder Head. This service is for an engine that does not blow blue smoke out the exhaust and burn/consume oil. Performing a professional valve job restores full compression, which allows the engine to start quicker, idle smoothly without stalling, and (if the ignition timing and carburetor adjustments are set correctly, too), it will produce full power at top governed speed. Click or tap here for cylinder head bolt torque specs. And if you've ever wondered how the K361 rocker arms receive plenty of oil to keep them lubricated, when the engine is running at full governed speed, internal air pressure from the downward stroke of the piston forces crankcase oil through the pushrod tubes onto the rocker arms. Prices may change without notice. [Top of Page] Prices are subject to change without notice. Professionally replace loose and/or broken OEM valve seat with a new high quality aftermarket hardened steel seat insert. $200.00 each for labor and new seat, plus return shipping & handing. Professionally repair loose valve guide (in head). $80.00 each for parts and labor, plus return shipping & handing. Regrind both valve faces and seats (perform valve job) to OEM specs, lap-in valves, install new valve stem seal, reinstall valves, springs, rotators and keepers/locks/collets. $60.00 labor, plus return shipping & handling. Resurface head gasket mating surface on a wide, flat sanding belt to remove any warpage and restore flatness. $40.00 labor, plus return shipping & handing. Complete Gasket Kit to Reinstall K361 Cylinder Head on Engine. $50.00 each, plus shipping & handling. (Each part included in the full gasket set.) Kohler Engine Model K361 (OHV 18hp) Cylinder Head Assembly. Professionally rebuilt and fully assembled. No cracks. Cooling fins, spark plug threads and bolt hole threads are all in good condition. Valve seats and/or valve guides reground, repaired or replaced, where applicable. Includes valves, springs, rotators, stabilizers and keepers. Cleaned and resurfaced on a wide, flat belt sander to remove any warpage and restore flatness. NOTE: If it's repairable and reusable, do not discard your cylinder head or other older Kohler engine parts. Most discontinued OEM Kohler parts in good, reusable, repairable or rebuildable condition are hard to find nowadays, and nothing works better than the original part(s) the engine is designed for. Each head listed below is used and in excellent condition. Discontinued Kohler part #'s 45 318 04 -S and 45 755 10-S. Complete Rebuilt K361 Head with rebuildable core trade-in/exchange. $400.00 each, plus shipping & handling. (When available.) Complete Rebuilt K361 Head. Outright with no core trade-in/exchange. $500.00 each, plus shipping & handling. (When available.) Gasket kit to reinstall rebuilt K361 cylinder head on engine. $50.00 each, plus shipping & handling. New head bolts. Fits Kohler engine model K361. 3/8" diameter x 1-1/2" thread length grade 8 bolts and hardened washers. OEM Kohler part #'s 270721-S (bolt; discontinued from Kohler), 270889-S (washer). Click or tap here for cylinder head bolt torque specs. High quality aftermarket. Set of 6 bolts only. $6.00 per set, plus shipping & handling. High quality aftermarket. Set of 6 bolts and 6 washers. $9.00 per set, plus shipping & handling. Please contact A-1 Miller's if you're interested in purchasing any of the products or services listed in this website. If you need a part or parts that's not listed in this website, please contact A-1 Miller's and we'll see if we can get it at a reasonable price. | [Top of Page]

Crankshaft Repairs-

• Regrind small engine crankshaft journal (crank pin). $50.00 per journal, plus return shipping & handling. Note: Kohler crankshafts can be reground to .030" undersize and still be safe to use with matching undersized bearing inserts installed in the connecting rod. And all crankshafts, rather if they're automotive or small engine, are checked for straightness before grinding. If they're bent or twisted, sometimes they can be straightened. We also do offset crankshaft grinding to increase the length of the stroke at no extra charge.
• "Round Up" Rod Journal(s) and Resize Connecting Rods. The service is for most makes and models of engines when an undersize connecting rod or bearing inserts isn't available, if the crankshaft is worn beyond .010" and needs to be reground again, the journal can be reground to wherever it "cleans up" or is true again, then the connecting rod can be resized so it'll fit the smaller undersize journal with the factory recommended .0025" oil clearance. To resize the rod so it'll fit to a few thousands of an inch smaller diameter crank journal, first, metal is removed from the mating end of the rod cap, then the cap is fasten to the rod. The big hole in the rod is now oblong or "egg shaped." Then the big hole in the rod is honed until it's .002" larger than the diameter of the crank journal. Honing reshapes the hole into a perfect circle again, only smaller in diameter. This works very well and it lasts as long as an ordinary STD size rod and crank journal. This can only be performed on a rod with a good bearing surface. It cannot be done on a burnt or heavily scored connecting rod because too much metal would need to be removed. If you're interested, I will need your crankshaft and connecting rod(s). NOTE - The maximum a connecting rod can be resized to is .005" undersize. If it's resized more than .005", being the big hole in the rod will be made excessively oblong or egg-shaped, which will allow it to make less bearing surface contact around the crank journal after being resized, due to the centrifugal force at 3,600 RPM, the big end of the rod could become elongated (metal stretch) and might eventually knock and possibly break. NOTE: Once installed and in operation, there is no warranty or guarantee of any kind on crankshaft regrinds.
  • Single cylinder engine crankshafts: $100.00 per journal, plus return shipping & handling.
  • Two cylinder engine crankshafts: $200.00 per journal, plus return shipping & handling.
• Repair broken off stud in crankshaft on flywheel end. $30.00 labor, plus return shipping & handling. We drill and cut threads for a hardened 3/8" or 5/8" diameter bolt in the end of the crankshaft to secure the flywheel.
• Drill hole and cut 7/16-20 UNC (fine thread) threads in the PTO end of the crankshaft for a retaining bolt and flat washer. $20.00.

The Reason For Superseded Part Numbers -

When President Nixon was in office, he placed a price freeze on all products being manufactured in the US at the time. The manufacturers couldn't raise their prices even if it cost them more to produce their parts. What happened was the government placed the freeze on the part number of each part. So manufacturers simply gave their parts a different part number so they could legally raise the prices. Return To Previous Paragraph È

Available Soon - Detailed Illustrated Plans on How to Construct a Professional Pull-Back and Self-Propelled Garden Tractor/Small Wheel Mini Rod Pulling Sleds (Weight Transfer Machines) - [Top of Page]

FYI - I'm getting closer to completing my sled plans. But being I have lots of work to do in my shop, I work on designing my sled plans in my spare time. As soon as my plans with an inventory list of parts to use and with illustrations are perfected, I'll post the announcement in my websites. And as for prices of the pull-back sled and self-propelled sled plans, I'm not sure yet. Make me an offer and I'll consider it. And remember - Perfection takes time. If it's worth having, it's worth waiting for. It'll be money well spent. Contact information below.

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Complete Narrowed Automotive Rear End/Differential for Use in Garden Tractor Pulling Sled - [Top of Page]

Details Include -

• When connected to an automotive 3- or 4-speed manual transmission, this narrowed rear end controls the movement of the weight box in a garden tractor pulling sled (weight transfer machine).
• Non-Posi-Trac automotive rear end with a low geared ring and pinion gear ratio.
• Professionally narrow axle housings and axle shafts as short as possible.
• Install a minimal tooth count sprocket for a #50 or #60 roller chain on right axle (when facing center yoke) and reinstall brake drum assembly on left axle (to act as the engagement/disengagement clutch for weight box) with a long emergency/parking brake cable.
• All rear ends will be narrowed as orders are placed. A minimum of 50% deposit is required on all narrowed rear end purchases.
• Complete Narrowed Automotive Rear End Assembly: $1,000.00 each, plus shipping and handling.
• Prices are subject to change without notice. And remember - Perfection takes time. If it's worth having, it's worth waiting for. It'll be money well spent. If interested, please contact below.

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To place an order, send your item(s) for repairing, and/or for customer service assistance, and FREE honest and accurate technical support, please contact: A-1 Miller's Performance Enterprises, 12091 N Route B, Hallsville, MO (Missouri) 65255-9604 USA. Please call in your order or send an email with a list parts you need and your contact information. Phone: 1-573-881-7229 (cell; call, text or leave voicemail). Please call Monday-Friday, 9am to 5pm, Central time zone, except holidays. If no answer, please try again later. E-mail: pullingtractor@aol.com. A-1 Miller's shop is open to the public Monday-Friday, 9am to 5pm, Central time zone, with an appointment on weekends, except holidays. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's new shop (click image to the right) to personally purchase parts, or drop off and/or pick up your carburetor, clutch assembly, and/or other parts for repairing and/or rebuilding. Or visit our new shop to drop off your parts. Please contact us before coming so we'll be at our shop waiting for your arrival. When you visit our shop, you will be dealing directly with the owner for the best customer service. "The road to a [trusted] friend's house (or shop) is never long." Don't sacrifice quality workmanship for distance. Payment Options below. Photos of our new building/shop are posted here! 12091 N Route B, Hallsville, MO - Google Maps. [Return To Previous Paragraph, Section or Website]

Payment Options, and We Ship to Canada and Worldwide
Item(s) in a package or cushioned envelope weighing less than 1 lb. is sent by US Postal Service Airmail Letter Post for a 4-7 days delivery. Packaged item(s) weighing over 1 lb. and up to 66 lb. is sent by US Postal Service Airmail Parcel Post for a 4-10 days delivery. I cannot use the US Postal Services' Flat Rate Priority Mail envelopes and boxes to ship outside U.S. territories. Item(s) weighing over 67 lbs. or more is sent by FedEx Ground or equivalent services. We try to keep our shipping cost to customers within reason. Therefore, we don't ship our products in a fancy-looking package with our company name and/or logo on it because most customers will just toss it in the trash after they remove the contents. And being there is no USPS tracking number outside the US, all I can do is make sure I write your address correctly on the customs form and on your package.

My websites are not set up to process orders and accept payments. Therefore, to place an order with me, please call either number above or send an email with a list of parts you need, with your name, complete and correct postal mailing address and phone number. For payment options, I accept cash (in person), USPS Postal Money Orders, cashier's checks, business checks, MasterCard, VISA, Discover, American Express (please add 2.5% to the total amount for the credit/debit card processor's surcharge). If paying with a credit/debit card, please call me at either number above. Or to make a payment to me through PayPal, please click this link: https://www.paypal.com. Or use Cash App (username: pullingtractor) or Venmo (username: Pullingtractor) to make a payment to me. And be sure to mention a description of what the payment is for with your full name, postal address, phone number and email address. If sending a money order or cashier's check, please include a note in the envelope with your name, complete mailing address, phone number, email address and a description of what the payment is for. I'll make a note of your order when I have all your information, and I may have to order some of the parts on your list, which should take a few days to come in, but I will send everything to you as soon as I have the parts in stock after I receive your payment.

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