Professional Kohler Engine Rebuilding, Buildups and Modifications

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How to Set the Governor Top Speed on a Kohler (or virtually any small engine)

Fabricate a Foolproof Type of Foot-Operated Spring-Loaded Throttle Return Control Setup on a Competition Pulling Tractor

Fabricate a Sliding Stranded Throttle Cable Control Setup for 10-16hp Kohler Engines

How to Limit the RPM and Safely Operate Virtually Any Small Engine Without a Working Governor

Learn What Type of Motor Oil Should Be Used in Lawn & Garden, and Competition Pulling Engines

How to Create a Hybrid Kohler Engine Model K261, K271, K281, K321, K371, K381 or K411

Lawn & Garden, Recreational Vehicle/Early Snowmobile Engine Rebuilding, Custom Engine Build-up Services

Competition Pulling Engine Building and Pulling Engine Freshening Service

Engine Dyno (Dynamometer) Service (Test Physical Horsepower and Torque)

Decoding Kohler Engine Model, Specification and Serial Identification Numbers -

The Kohler K-series and Magnum engine model and serial numbers appears on a decal or metal tag that's attached or affixed to the upper part of the flywheel shroud, or on the carburetor side of the flywheel shroud. If there's no tag or decal on the engine, or if the flywheel shroud has been replaced with one from another engine, then there's no way of knowing the exact replacement parts or the year of the engine. All you'll know is the model, specification and year of the flywheel shroud itself. Flywheel shrouds can be swapped from one engine to another and there are no identification numbers on the blocks themselves (except for the K241/M10, K301/M12 and K321/M14 engines, which has 9 cylinder head bolts, the K341/M16, which has 10 head bolts and the K361 18hp OHV is obvious). Therefore, the best way to find the size and model of Kohler engine is to remove the cylinder head and measure the bore and stroke. (Otherwise, they are like the small and big block Chevy V8's, there is no way of knowing for sure simply by looking at it on the outside.) Because a Kohler K241/M10 engine block can be bored and stroked to a model K301/M12, using the K301/M12 piston, rod and crankshaft, and a K301/M12 block can be bored to a model K321/M14 using the K321/M14 piston, rod and crankshaft. And the models K341/M16 blocks are in a class by themselves. And a K321/M14 block could be bored for the K341/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 with the cylinder wall. Therefore, I don't recommend doing this.

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

Engine Model K90/K91 K141 K141 K160/K161 K160/K161 K181/M8 K241/M10 K301/M12 K330/K331 K321/M14 K341/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

Factory-Rated Horsepower @
Maximum Safe Operating Speed
4hp @ 4,000 RPM 6¼hp @ 3,200 RPM 7hp @ 3,600 RPM 6¼hp @ 3,200 RPM | 6.6hp @ 3,600 RPM 7hp @ 3,600 RPM 8hp @ 3,600 RPM 10hp @ 3,600 RPM 12hp @ 3,600 RPM 12½hp @ 3,200 RPM 14hp @ 3,600 RPM 16hp @ 3,600 RPM 18hp @ 3,600 RPM

Minimum Safe Idle Speed (±75 RPM)

1,200 RPM
1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 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 - (To determine basic description of engine. More version codes further down. Ê)

Example of Model K160 -
K = K-series engine | 16 = Cubic inch displacement (approximate) | 0 = before Kohler designated 1 is for a 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 K161 -
K = K-series engine | 16 = Cubic inch displacement (approximate) | 1 = One/single cylinder engine. Example of Model M14PT -
M = Magnum series engine | 14 = Horsepower rating | PT = Pump model/Retractable start

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. Kohler changed the "0" to "1" or "2" at the end of the model number to indicate that it's a one or two cylinder engine. The History of Kohler Engines | eHow | Kohler Engines - RitchieWiki.

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

A = Narrow Base Block and/or Special Oil Pan
B = Basic Engine
C = Clutch Model (OEM Kohler Mechanical Clutch Assembly) G = Generator Application (Power Plant)
P = (Water) Pump Model
Q = Quiet Model (Quiet Line) R = Reduction Gear
S = Electric (Gear) Start
T = Retractable (Recoil) Start ST = Electric (Gear) Start and Retractable (Recoil) Start
EP = Electric (Power) Plant

Specification Numbers for Kohler K-series and Magnum Single- and Twin-Cylinder Engines - NOTE: The first two numbers of the specification numbers indicate the engine model. The three numbers and letter following the first two numbers (not shown below) are the specific variation of the engine to meet OEM equipment 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 = Model of Engine Specification = Model of Engine Specification = Model of Engine Specification = Model of Engine Specification = Model of Engine

26, 27, 31 = K90/K91 29 = K141 28 = K160/K161/L161 30 = K181/M8 46 = K241/M10

47 = K301/M12 60 = K321/M14 71 = K341/M16 23 = K361 24 = KT17, KT17 Series II, M18

49 = KT19, KT19 Series II, M20 32 = KT21 56 = MV16 58 = MV18 57 = MV20

35 = K482 53 = K532 36 = K582 37, 38, 43, 44 = K330/331 29, 30, 33, 39, 45 = K660/K662

Serial Numbers for Kohler K-series and Magnum Single- and Twin-Cylinder Engines - NOTE: 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 K160 engine (which is actually the K161) followed in 1952. No serial numbers are available these early model engines. In 1968, Kohler expanded into the recreational 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.

Letter code. E 1 7 2 4 5 2 (example)	If seven digit numbers, use the first two digits. 9 0 7 6 4 3 0 (example)	If eight digit numbers, use the first three digits. 1 0 0 2 6 6 9 2 (example)	If ten digit numbers, use the first two digits. 1 5 0 1 8 9 7 5 9 1 (example)
A............1965 B............1966 C............1967 D............1968 E...(early)1969	10-19...(late)1969 20-29...........1970 30-39...........1971 40-49...........1972 50-59...........1973 60-69...........1974 70-72...........1975 73-79...........1976 80-89...........1977 90-94...........1978 95-99...........1979	100-109.............1980 110-119.............1981 120-129.............1982 130-139.............1983 140-149.............1984 150-159...(early)1985	15...(late)1985 16...........1986 17...........1987 18...........1988 19...........1989 20...........1990 21...........1991 22...........1992 23...........1993 24...........1994 25...........1995

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
Maximum safe operating speed 1,200 RPM (±75 RPM)
3,200 RPM Breaker cam to camshaft pin .001" - .0025"

Cylinder Bore - Standard 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
- Models with Splash Lubrication .003" - .008"
.005" - .010" Valve stem in guide - Exhaust
- Intake .002" - .0035"
.002" - .005"

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
- 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, K160, K161 K181 K241 K301 K321 K341 K361
(Over Head Valve)

General Information Factory-Rated Horsepower @
Maximum Safe Operating Speed 4hp @ 4,000 RPM 6¼hp @ 3,200 RPM | 6.6hp @ 3,600 RPM | 7hp @ 3.600 RPM 8hp @ 3,600 RPM 10hp @ 3,600 RPM 12hp @ 3,600 RPM 14hp @ 3,600 RPM 16hp @ 3,600 RPM 18hp @ 3,600 RPM

Minimum Safe Idle Speed (±75 RPM) (See note 11 below) 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 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 Gear Shaft O.D. New - - - <-.4998"-.5001"->

Maximum Wear Limit - - - <-.4996"->

End-Play/Clearance - - - <-.002"-.010"->

Camshaft End-Play/Clearance (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"->

Rod to Journal Side Clearance <-.010"-.025"->

Wrist Pin Hole I.D. .5630" (min.)
.5633" <-.6255"-.6258"-> .8596" (min.)
.8599" <-.8757"-.8760"->

Crankshaft Main PTO 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"->

End-Play/Clearance (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 316 or Champion 884 (H10C)->

Battery <-.035"->

Magneto <-.025"->

LP/Propane <-.018"->

Nominal Point Gap or Degrees BTDC (See note 12 below) <-.020" or 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)-> 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 RPMs 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 - Champion spark plugs or equivalent.
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 is for fresh reground valve faces and seats (As the valve and seat wear into each other, the clearance will be lessened.)
NOTE 10 - Use the lesser clearance for up to 3,600 RPM operation, and use the greater clearance for higher RPM or wide open throttle operation.
NOTE 11 - Idle speed should set around 1,200 RPM (±75 RPM) so the flywheel fins can blow plenty of cool air across the cylinder head and around the cylinder fins. Plus, the faster idle speed allows the crankcase oil to lubricate the internal moving parts better.
NOTE 12 - Use feeler gauge to set points gap at .020" with piston positioned at TDC on the compression stroke, or set ignition timing precisely at 20º BTDC with piston positioned at TDC on the compression stroke, adjust/set points gap when they just begin to open (use test light or ohmmeter) with S mark on flywheel centered with hole in bearing plate or aligned exactly with raised boss on bearing plate.

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

Engine Model M8 M10 M12 M14 M16

General Information Factory-Rated Horsepower @ Maximum Safe Operating Speed (See note 8 below) 7hp @ 3,200 RPM
8hp @ 3,600 RPM 9hp @ 3,200 RPM
10hp @ 3,600 RPM 10.6hp @ 3,200 RPM
12hp @ 3,600 RPM 12.4hp @ 3,200 RPM
14hp @ 3,600 RPM 14.2hp @ 3,200 RPM
16hp @ 3,600 RPM

Minimum Safe Idle Speed (±75 RPM) (See note 9 below) 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 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 Gear Shaft O.D. New - <-.4998"-.5001"->

Maximum Wear Limit - <-.4996"->

End-Play/Clearance - <-.002"-.010"->

Camshaft End-Play/Clearance (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"->

Rod to Journal Side Clearance (min.-max.) <-.010"-.025"->

Small End I.D. (max.) .6255"-.6258" .8596"-.8599" <-.8757"-.8760"->

Crankshaft Main PTO 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"->

End-Play/Clearance (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) RCJ-8 <-RH-10->

Gap <-.025"->

Module Air Gap <-.012"-.016->

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 RPMs creates more heat due to friction, which causes greater expansion of parts.
NOTE 2 - Champion spark plugs or equivalent.
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 for a valve that have been ran for a while, and use the greater clearance for fresh reground valve faces and seats. (As the valve and seat wear into each other, the clearance will be lessened.) NOTE 7 - Use the lesser clearance for up to 3,600 RPM operation, and use the greater clearance for higher RPM or wide open throttle operation.
NOTE 8 - To prevent a lean air/fuel mixture with a fixed/non-adjustable high speed main jet Walbro carburetor, set engine at maximum 3,200 RPM. And with a fully adjustable high speed main jet Carter, Kohler or Walbro carburetor, set engine at maximum 3,600 RPM.
NOTE 9 - Engine should idle around 1,200 RPM (±75 RPM) so the flywheel fan blades can blow plenty of cool air over the cylinder fins, and the faster idle allows oil in the crankcase lubricate the internal moving parts better.

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

Engine Model MV16 M18, MV18 M20, MV20 KT17, KT17 Series II KT19, KT19 Series II K482 K532 K582 K660/K662

Factory-Rated Horsepower @ Maximum Safe Operating Speed (See note 2 below) 14.2hp @ 3,200 RPM
16hp @ 3,600 RPM 16hp @ 3,200 RPM
18hp @ 3,600 RPM 17.8hp @ 3,200 RPM
20hp @ 3,600 RPM 17hp @ 3,600 RPM 19hp @ 3,600 RPM 18hp @ 3,600 RPM 20hp @ 3,600 RPM 23hp @ 3,600 RPM 24hp @ 3,200 RPM

Minimum Safe Idle Speed (±75 RPM) (See note 7 below) 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM 1,200 RPM

Engine Construction <-Aluminum Block / Cast Iron Cylinders-> <-Cast Iron Block w/Integrated Cylinders->

Cubic Inch Displacement
(STD Bore) 42.18 42.18 47.00 42.18 47.00 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 5.8:1 6.4:1 7:1 ?

Piston Stroke <-2.750"-> 3.062" 2.750" 3.062" 2.875" 3.000" 3.000" 3.250"

Cylinder Bore (New) <-3.125"-> 3.250" 3.375" 3.500" 3.625"

Cylinder Bore (Worn) <-3.128"-> 3.253" 3.378" 3.503" 3.6245"

Cylinder Taper <-.0015"-> .002"

Cylinder Out
of Round <-.002"-> <-.005"->

Crankshaft End-Play/Clearance (Engines w/Sleeve Bearing) <-.002"-.014"-> <-.004"-.010"-> .0035"-.0055"

Crankshaft End-Play/Clearance (Engines w/Ball Bearing) <-.002"-.023"-> --

Crankshaft Main Front / Rear 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 Front / Rear Diameter (Engines w/Ball Bearing) <-1.378"-> <-1.772"->

Crankshaft Main Sleeve
Bearing Oil Clearance <-.0013"-.0033"-> <-.0015"-.004"-> ?

Crankpin
New Diameter <-1.3733"-1.3738"-> 1.500" 1.3733"-1.3738" First Design - 1.3733"-1.3738"
Series II - 1.4993"-1.4998" <-1.625"-> ?

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"-> First Design - 1.376"
Series II - 1.5025" <-1.627"-> ?

Connecting Rod Big End to Crank Pin Clearance <-KT17 First Design and KT19 First Design 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" .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" <-.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 <-.003"-.006"-> <-.008"-.010"-> .006"-.008"

Exhaust Valve to Tappet
Clearance Cold <-.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 Clearance in Guide <-.0005"-.0024"-> <-.0012"-.0023"-> ?

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 Nominal Gap <-N/A-> <-.017"-023" (See note 6 below)-> <-.020"->

Ignition Timing Spark Run <-N/A-> <-23º BTDC-> <-22.5º BTDC-> ?

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 with a fixed/non-adjustable high speed main jet Walbro carburetor, set engine at maximum 3,200 RPM. And with a fully adjustable high speed main jet Carter, Kohler or Walbro carburetor, set engine at maximum 3,600 RPM.
NOTE 3 - 1,800 RPM Generator Engines .015" Spark Plug Gap and 16º BTDC Timing.
NOTE 4 - 3/8" Screw - 300 in. lb. NOTE 5 - 5/16" Screw - 250 in. lbs.
6 Or set points gap at zero and just begin to open when roll pin on #1 cylinder is aligned with S mark on flywheel..
NOTE 7 - Engine should idle around 1,200 RPM (±75 RPM) so the flywheel fan blades can blow plenty of cool air over the cylinder fins, and the faster idle allows oil in the crankcase lubricate the internal moving parts better.

Kohler Fastener Torque Values and Sequences

Model (Horsepower)		K90/91	K141, K160/K161	K181/M8	K241/M10, K301/M12 and K321/M14	K341/M16	K361	KT17, KT17 Series II, KT19, KT19 Series II, 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 @ 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 L161 (Water-Cooled) 7hp Parts Manual
Kohler Engine Model K181 (Air- and Water-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, KT17 Series II, KT19, 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

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

Unlike the small block Chevy V8's, the Kohler K-series and Magnum engine block models K241/M10, K301/M12, K321/M14 and K341/M16 are not all the same. There are many variations in bolt patterns and PTO 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 pictures 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 and K341/M16 Kohler Engine and Blocks -

The K241/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/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/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 or K321/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 and K321/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/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/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 or K321/M14 and K341/M16 engines, except the valves are the same diameter, 1.375" and the K341/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/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 or K321/M14 and K341/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 (Cub Cadet, John Deere, Wheel Horse or Ford).
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 sheet metal that covers the block, the Magnum has solid state ignition, a fixed main jet (Walbro) carburetor and the starter fastens to the 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/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 Chevrolet small block or big block V8's. 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 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 bearing plate with an upper mount gear starter (mounting bolts are below the starter motor), or a small K-series bearing plate with a starter/generator; a small or large diameter K-series flywheel with a matching flywheel shroud and 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. Also, because of the 3/8" flywheel retaining bolt, an aluminum clutch hub adapter with a 3/8" hole will need to be used, acquire a 5/8"-3/8" reducer/step washer. (I make these.) Everything else should fit in the tractor with no problems.

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 model 1050); M12, specification #'s 471512, 471514, 471570 (Cub Cadet model 1210); M14, specification #'s 601512, 601513; and M16, specification # 711536. All other 10-16hp Magnum engine block specification numbers are a wide base.

Kohler's Dynamic Balance System 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 crank trigger ignition system will 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.

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

To convert a Kohler K-series 10-16hp engine into a Magnum engine, the parts that's needed are: Magnum bearing plate; starter motor; flywheel (w/external magnet), plastic cooling fan assembly, flywheel shroud/air baffles (sheet metal), plastic inner air baffle, and the solid state ignition coil w/mounting screws. (The support brackets for the starter are for mounting of the starter solenoid only. They do not support the starter motor whatsoever.) The Kohler points pushrod hole will 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 warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities and 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.

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 sanding disc to remove the warpage and restore flatness. Resurfacing the cylinder heads on a wide, flat belt sander to remove 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.

Why OEM OHV V-Twin Aluminum Block Engines Don't Work Well for High Performance/High 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 picture 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.)

Referring to the pictures 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 lost their torque again the metal. If no gasket was used, and a thin bead of RTV silicone sealant was applied instead between the crankcase and closure plate (and the necessary thrust washers and shims installed to control the crankshaft and camshaft end-play/clearance), 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 and 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. I think that Kohler is the best engine for pulling. They're the "Chevrolet" of garden tractor 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 high RPM or at wide open throttle. This is why most riding mowers, lawn tractors and lawn and garden tractors have aluminum block engines. And most garden tractors have a cast iron engine block.

In addition, on the cast iron block single cylinder Briggs and 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 high RPM or at wide open throttle, 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 sanding belt or large diameter disc sander to remove the 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.

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. That's why cast iron Kohler engines work best for competition pulling. Because cast iron is able to "hold its shape," handle high operating temperatures, severe stress, high compression and at high RPM or at wide open throttle. This is why riding mowers, lawn tractors, lawn and garden tractors all have aluminum block engines. And most garden and larger tractors have a cast iron engine block.

How to Repair a Worn Crankshaft Main Bearing Surface in a Kohler Command CH-series Engine Block -

When the crankshaft main bearing aluminum surface in a Kohler Command block is worn beyond specifications, the hole can be precision-bored for installation of a bearing bronze bushing, then the I.D. of the bushing will need to be honed or bored larger to match to diameter of the crankshaft main journal with the proper oil clearance. And then either a drilled hole or a channeled groove will need to be machined in the bushing for lubrication. I haven't performed this type of repair yet, but I talked to several reputable machinists who have done this with excellent results. - Brian Miller

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

The alternative to using a V-twin engine in a Cub Cadet 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 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), and the carburetors can be easily adjusted or synchronized without one running engine interfering with the other, unlike in a "direct-coupled together" configuration.

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, KT17 Series II, KT19, KT19 Series II, and KT21 (snowmobile engine) all have a gear-driven gerotor oil pump, and use one of two types of pressurized lubrication systems.

The KT17 and KT19 first design engines use a pressurized SPRAY lubrication system. The oil pump delivers oil to the main bearings and camshaft bearings at approximately 5 PSI. Lubrication for the connecting rod journals is provided by oil sprayed from two small holes drilled in the camshaft in alignment with the connecting rods. The main bearings are under pressurized oil, but the connecting rod journals receive oil that's constantly sprayed through drilled holes in an oil passageway in the camshaft. These are very well-designed engines, but have gained a bad reputation because either the wrong velocity of oil is used and/or the crankcase oil was not changed on a regular basis.

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. What causes the rod failure is if the motor oil isn't changed on a regular basis (once a year or every 25 hours of run time) and/or using non-detergent motor oil, 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. If the crankshaft main journals are worn beyond specifications, the main journals can be reground to .010" or .020" undersize, and matching undersize main bearings will need to 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, one main journal can be reground undersize if it's worn beyond specifications (mostly likely the PTO end), and the other (most likely the flywheel end) can remain STD size if it's within specifications. (STD size or .010" undersize for the front main, and .010" or .020" undersizes for the rear main.)

The reason Kohler didn't provide provisions for an oil filter on the KT17 and KT19 first design engines is because again, being these engines produce about 5 PSI oil pressure, there wouldn't be enough oil pressure to pump through the filter and then to the main bearings and spray on the rod journals. Also, being there's no provision (port) 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 an oil drain plug with a very strong rare earth/neodymium magnet, or glue a very strong rare earth/neodymium magnet to the inside bottom of the oil pan or engine base to attract steel or cast iron metal 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 quality 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.

(Added 7/22/20) Something to ponder - The crankshaft and camshaft out of a Kohler KT17 or 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, for longer engine life.

How to Convert a Kohler Magnum M18 or M20 Crankshaft for Use in a Kohler KT17 or KT19 first design Engine - (Added 4/29/19)

When a replacement crankshaft for a Kohler KT17 or KT19 first design engine that's in good (unworn) condition cannot be found, and being the factory drills oil galley holes in the Kohler Magnum M18 and M20 crankshafts (before the deep heat-treating process of the journals to reduce surface wear), drilling new oil galley holes in a KT17 or KT19 first design crankshaft can be very difficult due to the hardened surface metal.

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 can be machined shorter for use with the horizontal shaft engine's particular application.

Anyway, the crankshaft out of a Magnum M18 (for the KT17) or M20 (for the KT19) can be used instead. The drilled oil galley holes in the Kohler Magnum M18 or M20 crankshaft will need to be blocked-off/plugged when replacing either of these crankshafts in a Kohler KT17 or KT19 first design engine to maintain proper oil pressure through the camshaft so it can spray sufficient amount oil on the connecting rods.

To make this work, use a 12-24 UNC taper hand tap to cut shallow threads in the drilled oil galley holes, and then install 12-24 UNC x 3/16" length Allen set screws in the tapped holes. Be sure to apply high strength liquid threadlocker (Red Loctite or Permatex) on the threads of the Allen set screws to secure them in the crankshaft. Also, tighten the set screws securely, and make sure the end of the set screw is below the surface of the main journals.

And being the oil pump in the KT17 and KT19 first design engines produce about 5 PSI oil pressure, plugging the oil galley holes in the Magnum crankshaft will allow the oil pump provide maximum pressure and full flow through the camshaft to sufficiently lubricate/spray the connecting rods and lubricate the main journals. And do not attempt to drill out/enlarge the oil spray holes in the camshaft! Doing this would allow more oil to be sprayed on the #2 rod and less oil on the #1 rod.

On the other hand, the redesigned KT17 Series II and KT19 Series II (including all Magnum 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 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 twin cylinder engines. If there's no oil filter on a KT17 Series II, KT19 Series II or any Magnum twin cylinder engine (oil adapter port blocked off), it's still important to change the oil on a regular basis with these engines, too. Again, fresh oil is cheaper than an engine or engine rebuild. 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).

If you've ever wondered what the differences between the cylinders/jugs on Kohler engine models KT17 (first design), KT17 Series II, KT19 (first design), KT19 Series II, MV16, M18, MV18, M20 and MV20, well, here are the differences...

The Kohler KT17 first design and KT19 first design engine cylinders are similar to the MV16, M18 and MV18 cylinders, but does not have the bosses for mounting the solid state ignition coil bracket.
The KT17 Series II and KT19 Series II cylinders have the bosses, but are not drilled and tapped.
The KT19 first design, KT19 Series II, M20 and MV20 cylinders are 1/4" wider (from measured from crankcase mounting surface to head gasket surface) than the KT17 first design, KT17 Series II, MV16, M18 and MV18 cylinders.
The valves in the KT17 first design, KT17 Series II, MV16, M18 and MV18 have the same dimensions.
The valves in the KT19 first design, KT19 Series II, M20 and MV20 have the same dimensions, but are .285" longer than the KT17 first design, KT17 Series II, MV16, M18 and MV18 valves.
The KT17 first design, KT17 Series II, MV16, M18 and MV18 cylinders have 10 cooling fins, and the KT19 first design, KT19 Series II, M20 and MV20 cylinders have 11 fins. There's also an obvious difference in the shape of the fins that's close to the crankcase.
The extended part of the cylinder walls on the KT17 first design, KT17 Series II, MV16, M18 and MV18 are curved, and the extended part of the cylinder walls on the KT19 first design, KT19 Series II, M20 and MV20 are flat.
The cylinders for the KT17 first design, KT17 Series II, MV16, M18 and MV18 engines will NOT interchange with the KT19 first design, KT19 Series II, M20 and MV20 engines. By the way - the crankcase halves are the same on all of these engines, with 5/16" studs to match the mounting holes in the cylinders, except the KT17 first design crankcase halves have 3/8" studs with 3/8" holes in the cylinders.

FYI- Boring the cylinders to a maximum of .030" and installing .030" oversize piston and rings will not help to increase the power much at all. It'll only add about 1/10^th of a horsepower with virtually no increase in torque. What increases engine 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 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 cast iron block Kohler flathead engine on a motorcycle or any lightweight recreational vehicle. 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 other lightweight recreational 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]

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

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, KT17 Series II, KT19, KT19 Series II, M18, M20, and perhaps KT21: intake manifold, closure plate (to replace the oil sump cover), oil pickup tube with the strainer, governor linkage parts, 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 number of engine models that was manufactured by Kohler.

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

The parts needed to convert a Kohler Command Pro V-Twin vertical shaft engine into a horizontal shaft engine are as follows. The parts 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, throttle linkage and carburetor will also need to be swapped.
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.

By the way - I don't build high performance V-twin engines and I know very little how to improve the performance of them because no one here in Missouri pulls them. The only contacts I have concerning V-twin engine builders and high performance parts are listed below Ê. Contact them and perhaps they can help you.

Al Hodge Performance V-Twins of Monroe, NC. He modifies the Briggs & Stratton Vanguard V-twins for all types of racing and performance applications. Output ranges from 25 to 42hp. Modified engine weight is around 80 lbs. He supplies engines for some of the fastest Cushmans in the National Champion lawn mower racers, tractor pullers, Class Champion scale sprint cars, ATV's, hunting boat upgrades, etc. All of his engines are non-governed and include solenoid shift, high torque starters. Sorry, he doesn't have a manual or any printed literature....he offers cams, billet rods, high compression pistons, mega-valve machine ported heads, titanium valves, rev-kits, roller rockers, billet push rods, billet rocker covers, stroker kits, etc. Give Al a call @ 704-291-7825 Monday thru Friday 10:00 am until 4:00 pm EST. E-mail: pki@trellis.net.
R.P.M. - Rader Performance Motors When Performance Counts, Count on Rader Performance Motors! Services Include: Complete Engine Building - Stock, Stock-Altered and Kohler V-Twins Custom Flow Bench Water Brake Dyno Tuning = Maximum Horsepower Dyno Tested, Track Proven Performance Contact: Mark Rader of Pataskala, OH | Phone: 740-927-3312 | E-mail: RPMark@sprintmail.com.
Frank Edwards of Galax, VA. Kawasaki water cooled V-Twin garden tractor high performance. Selling performance parts and building complete pulling engines. Call for details. 276-236-5305. E-mail: sdrawde@ntelos.net.
Lakota Racing ( http://www.lakotaracing.com/ )
Midwest Super Cub ( http://www.midwestsupercub.net/ )
Performance V-Twins ( http://www.performancevtwins.com/ )

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 twin cylinder flathead B&S engine into a horizontal shaft model are as follows. The parts below Ê must come off a horizontal shaft 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 controls off 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 twin cylinder engine into a Cub Cadet, 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 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: http://www.smallenginewarehouse.com/RepowerItems.asp?Brand=Cub%20Cadet&Model=1000.

IMPORTANT! When rebuilding an aluminum block engine, remember - as an aluminum block and cylinder head get hot for the first time, they "warp" or bend and twist a few thousands of an inch due to normal engine heat. This is called block (and related parts) warping. In other words, the metal "takes shape." It's normal for new engine parts and unavoidable. So be sure to have the cylinder head and other parts resurfaced on a wide flat sanding belt or large diameter disc sander to remove warpage and restore flatness, and to ensure 100% gasket sealing, and bore the cylinder to ensure a 100% piston ring seal. After the parts get hot again, they should not bend and twist 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. I 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 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. I think the older Kohler engines are the "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 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 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. Do not use soapy water to perform this test because the water content will cause the 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 picture to the right è to watch how this test is performed on YouTube. By the way - The video shows both valves fully closed with the piston positioned at 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.

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

With the piston is positioned exactly at Top Dead Center (TDC) on the compression stroke, the automatic compression release (ACR) mechanism allows the exhaust valve to fully close, then a leak down test can be performed. The ACR effects a compression test when performed with a compression tester, but not a leak down test (as long as the piston is at TDC on the compression stroke). 0º TDC is when the piston is at its very top in the cylinder with both valves fully closed. It is also when the T mark on the flywheel is aligned with the raised boss on the bearing plate, and The alignment can be seen with a flashlight through the sight hole in the bearing plate. But the best way to determine if an engine needs to be rebuilt is to remove the cylinder head & look at the edge of the piston. If the carbon is washed away, this means the rings & piston are worn and the engine needs rebuilding.

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, 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 RPMs 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, 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 specialty tools are required to disassemble, reassemble and rebuild a single- or 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)
Piston ring compressor
Quality-made automotive harmonic balancer puller to remove the flywheel

Valve lapping tool and valve grinding compound (which can be purchased online and at virtually any auto parts store)
Feeler gauge set to set the valve clearances, camshaft end-play/clearance and crankshaft end-play/clearance
Two torque wrenches that reads in inch- and foot-pounds of torque
Multimeter set on Ohms resistance or test light and two small jumper wires to set ignition timing

More sophisticated tools or tooling and machinery is required to perform machine work on certain engine components, such as: bore the cylinder, regrind the crankshaft journal(s), bore connecting rod for installation of replaceable bearing inserts, recut or reground the valve faces and seats, automotive ignition distributor clamp wrench (to fasten cylinder nuts on opposed twin cylinder engines), etc. In most cases, the valves can be reground. But if they're severely worn, they need to be replaced. I sell most of the parts required to perform a complete engine rebuild. Most common parts are: piston and rings, gaskets w/oil seals, valves, carburetor kit and tune up kit.

IMPORTANT! How Replaceable Bearing Inserts (Rod Bearings) Protect An Engine -

Due to the lack of or an insufficient amount of oil in the crankcase, or at high RPM or at wide open throttle 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 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 RPMs, 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 aluminum alloy inner layer that makes contact with the crank journal. These type of bearing inserts are rare, and should NEVER be used in a high RPM or wide open throttle engine because aluminum cannot handle heat as well as lead. Aluminum bearing inserts (used in various newer automotive engine steel rods) are not high performance, and should only be used with full synthetic motor oil in a full pressure oil pump lubricating system. Aluminum bearing inserts have no heat-resistant lead coating and when used in a high RPM or wide open throttle 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 better yet, with full synthetic motor oil.

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 burnt or scored 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.

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

Information About the Engine Governor (RPM Regulating) System -

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 replaced with new ones. This means the entire engine must be completely disassembled, and then governor gear and stub shaft can be replaced. I 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 picture 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 clean motor oil if the engine is going to be operated right away, or automotive chassis grease for long-term storage of the engine for lubrication and to prevent the stub shaft from rusting due to high humidity inside the engine block. 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 -

The entire engine must be completely disassembled, including everything inside the engine.
Remove the governor gear retaining screw (the Phillips head screw that's on the outside of the block).
The governor gear can now slide off the stub shaft.
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 lube or wheel bearing grease to prevent the governor gear from wearing until the crankcase oil reaches these areas.
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/M8, K241/M10, K301/M12, K321/M14, K341/M16 and K361 -

Remove the governor gear assembly and retaining pin as described above È.
There's no need to drill through and pry out the welch plug from outside the block! Instead, simply remove the cam gear cover, and through the cover opening, use a long 5/16" steel rod with a blunt end and medium size hammer to drive the welch plug from the block. The welch plug rests against a shoulder in a counterbore. Therefore, it MUST be removed from inside out.
Remove the exhaust valve spring, and going through the welch plug hole opening from the outside, use a 5/16" blunt punch and medium size hammer to drive the stub shaft from the block into the valve spring compartment.
To install the new stub shaft and to drive it straight in 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 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 vernier caliper will not need to be used.
If the welch plug is not damaged, it can be reused. To reinstall it securely and correctly, place it over a 7/8" I.D. heavy wall steel tube or a 7/8" socket and use the ball end of a ball peen hammer with a larger hammer to pound the center of the plug so it will become concaved (dish-shaped) with the center depressed enough so it will fit snug in the counterbore hole.
Clean out the counterbore machined step, and apply clear RTV silicone adhesive sealant in the step of the counterbore. 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 and 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.
Place the welch plug in the counterbore with the raised center facing outward. Use the ball end of the ball peen hammer with the larger hammer to pound the center of the plug so it will flatten out and expand, and fit tight in the counterbore hole.
Wipe away any excess silicone for a professional-looking job, and the repair is complete!

How to Set the Governor Engine Speed Control - [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.

A nylon governor gear assembly works best if an engine will never run above 4,000 RPM. But if you're going to pull competitively with an engine and disconnect the governor to run the engine at wide open throttle, then it's best to install a cast iron governor gear assembly. Because nylon could explode due to the increased RPM.

And if you've heard that by drilling a hole through the flyweights on the governor gear assembly to lighten them will improve engine performance, well, first of all, the flyweights are made of extremely hardened material for obvious reasons. Therefore, there is no way to drill a hole through them. It's even hard to grind metal off of them. Besides, lightening the flyweights will not help to improve engine performance whatsoever. All it'll do is allow the engine to rev up more, nothing else.

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. Or, you could disconnect the governor link from the carburetor and wire the arm to the exhaust pipe. This will prevent the nylon governor gear from possibly being damaged at high RPM. But then you must fabricate a throttle linkage of some kind to activate the throttle on the carburetor. For safety reasons, install a steel flywheel and crankcase side shields on an engine with no operating governor!

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, then...

First thing to check is, on the 10-16hp Kohler engines, there's a tiny blind-end needle bearing (older models) or steel bushing (newer models) that's pressed in block opposite 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. The end-play/clearance of the governor cross shaft needs be approximately .010". The end-play/clearance is set by driving the cross shaft and/or steel bushing back and forth with a small hammer until proper clearance is acquired. If the cross shaft has excessive end-play/clearance in the block, 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 engine models K141, K160/K161, K181/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.

To set the governor speed control on Kohler twin cylinder engine models MV16, KT17, KT17 Series II, KT19, KT19 Series II, M18, MV18, M20 or MV20, 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 clockwise with ordinary pliers or locking pliers (Vise Grip) as far as it will go, and then securely tighten the clamping bolt/nut.

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 or engine block. 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 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 clean motor oil, gear oil or lubricating grease on shaft for smooth governor action and less wear to shaft and/or bushing.

On rare occurrences, on Kohler engine models K241/M10, K3001/M12, K321/M14, K341/M16, K361 and the twin cylinder flathead engines, the hole in the 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 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 positively bonded together. And if the lever and/or governor needs to be serviced or removed for whatever reason, just grind away the weld.

And that's all that's to it! You can also go here for further details and pictures: 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 end-play/clearance, 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 end-play/clearance. 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 link 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 link adjustable. It serves no purpose to lengthen or shorten it.

How to Set the Engine Governor RPM Speed on a Single Cylinder Kohler K-series or Magnum Engine -

To set the RPM speed lower, so the engine will run slower, connect one end of the governor spring to one of the uppermost holes in the [reversed] L-shaped governor lever, and then connect the other end of the spring in one of the lowermost holes in the short speed control lever that's fastened to the block just under the carburetor or on the flywheel shroud (AQS/Quiet Line models).
To set the RPM speed higher, so the engine will run faster, connect one end of the governor spring to one of the lowermost holes in the [reversed] L-shaped governor lever, and then connect the other end of the spring in one of the uppermost holes in the short speed control lever that's fastened to the block just under the carburetor or on the flywheel shroud (AQS/Quiet Line models).
And it's best to use an accurate small engine tachometer to determine the exact RPM of the engine to prevent from dangerously over-revving, which could possibly cause the connecting rod to break. The top RPM limit for virtually any stock small gas engine with a carburetor having an adjustable high speed main jet, is 3,600 RPM; and an engine with a carburetor having a fixed/non-adjustable high speed main jet, the top RPM is 3,200. For a stock competition pulling engine, set it at 4,000± RPM, or whatever the sanctioning rules require. With certain tachometers, the RPM reading will need to be doubled for engines with camshaft-operated ignition points. With crankshaft-operated points or with solid state ignition, the reading will not need to be doubled.

Governor Gear Assemblies and Related Parts - [Return To Previous Paragraph, Section or Website]

Thrust Washers for Governor Gear Assemblies. 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 RPMs. Many people are not aware of this small, thin 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: Due to high RPM and pressure of the governor gear upon engine start-up, before installing, lubricate the stub shaft and thrust washer with motor oil, automotive chassis lube or wheel bearing grease to prevent the governor gear from wearing until the crankcase oil reaches these areas.

Heat-Treated, Hardened, High Carbon Steel Thrust Washers. Much harder than a grade 8 flat washer. Recommended and suitable with a nylon governor gear assembly. Dimensions: .032" thickness x .380" I.D. x .686" O.D.

High quality aftermarket. Replaces Kohler part # 237022-S. $1.00 each, plus shipping & handling.
Heat-Treated, Hardened, High Carbon Steel Thrust Washer. OEM Kohler part # 237022-S. $5.00 each, plus shipping & handling.

Bronze Thrust Washers. Harder than cast iron. Recommended and suitable with a cast iron governor gear assembly. Dimensions: .063" thickness x .380" I.D. x .757" O.D.

High quality aftermarket. Replaces Kohler part # X-25-67-S. $1.00 each, plus shipping & handling.
Bronze Thrust Washer. OEM Kohler part # X-25-67-S. $3.00 each, plus shipping & handling.

Governor Gear Stub Shafts. Fits Kohler engine models K141, K160/K161, K181 and M8. Dimensions of each part below: 3/8" diameter x .625" length. Each is press-fit into block. NOTE: Drive in the stub shaft until .345" (11/32") protrudes from the block.

High quality aftermarket. Precision ground, hardened, heat-treated alloy steel. $10.00 each, plus shipping & handling.
OEM Kohler part # 230125-S. $24.53 each, plus shipping & handling.

Governor Gear Stub Shafts. Fits Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16, K361 and all KT-series and Magnum opposed (flathead) twin cylinder engines. Dimensions: 3/8" diameter x 7/8" length. Each is press-fit into block. NOTE: Drive in each stub shaft until .345" (11/32") protrudes from the block.

High quality aftermarket. Precision ground, stainless steel material. $10.00 each, plus shipping & handling.
OEM Kohler part # 235125-S. $51.41 each, plus shipping & handling.

1-1/8" Steel Welch Plugs to block access to governor gear stub shaft. Concave/dish-shaped, not cup-shaped. Expands and flattens out with medium size ball peen hammer when installed in counterbore hole with clear RTV silicone adhesive sealant.

High quality aftermarket. $1.00 each, plus shipping & handling.
OEM Kohler part # X-230-11-S. $1.57 each, plus shipping & handling.

Governor Cross Shafts. Fits Kohler engine models K141, K160/K161 and K181/M8. New shaft includes thrust washer. Steel spacer for this shaft (part # 25 112 17-S) no longer available from Kohler. The lever on these rarely break off. NOTE: Before installing, apply clean motor oil, gear oil or lubricating grease on shaft for smooth governor action and less wear to shaft and/or bushing. OEM Kohler part # 230540-S.

Used and not welded. $20.00 each, plus shipping & handling.
Used and welded. $25.00 each, plus shipping & handling.
New and not welded. $57.65 each, plus shipping & handling.
New and welded. $62.00 each, plus shipping & handling.

Steel Spacer Washer. Fits all Kohler engine models K141, K160/K161 and K181/M8. Used on governor cross shaft above. Butts against governor cross shaft bushing (below) to maintain proper alignment of lever on cross shaft with center button on governor gear.

High quality aftermarket. .50¢ each, plus shipping & handling.
OEM Kohler part # X-25-58-S. $2.45 each, plus shipping & handling.

Governor Cross Shafts. Fits Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361. New shaft includes steel spacer. NOTE: The lever on these sometimes break off. 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. And before installing, apply clean motor oil, gear oil or lubricating 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 E-clip instead of spacer to the right). OEM Kohler part # A-235256-S.

Used and not welded. $10.00 each, plus shipping & handling.
Used and welded. $15.00 each, plus shipping & handling.
New and not welded. $29.75 each, plus shipping & handling.
New and welded. $35.00 each, plus shipping & handling.

Steel Spacer. Fits Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361. Used on governor cross shaft above. Butts against governor cross shaft bushing (below) to maintain proper alignment of lever on cross shaft with center button on governor gear. Dimensions: .260" I.D. x .372" O.D. x 13/16" length.

High quality aftermarket. $1.00 each, plus shipping & handling.
OEM Kohler part # 25 112 17-S. $6.10 each, plus shipping & handling.

Governor Cross Shaft Bushings with a rubber lip oil seal or snug-fitting neoprene rubber O-ring installed in machined counterbore to prevent dust and dirt/debris from wearing the bushing and/or shaft and prevent messy film of oil on outside of engine. Seal fits snug in bushing and on shaft, and has no effect with operation of governor whatsoever. WHY THIS IS IMPORTANT: Vacuum within the engine crankcase created by the upward stroke of the piston draws in air, along with dust, dirt/debris through the bushing/shaft, and then pressure created by the downward stroke of the piston blows out a fine mist of oil through the bushing/shaft. Overtime, the dust, dirt/debris cause the bushing (and sometimes the shaft, too) to wear, which also leaves an oily mess on the outside of the engine. IMPORTANT: When removing the old bushing, use caution not to drop the governor cross shaft down inside the crankcase! And before installing the new bushing, apply clean motor oil, gear oil or lubricating grease on the shaft for less wear to the shaft, seal and/or bushing, and for smoother throttle action. An ingenious and innovative concept by Brian Miller. Please accept no advertised copycat products of this kind. (But I do appreciate them acknowledging my intelligence.)

Governor Cross Shaft Bushing with 7/32" hole. Fits Kohler engine models K90/K91, K141, K160/K161 and K181 w/specification # 30100-30848 and various early M8 engines with V-shaped/coiled governor spring behind bushing. NOTE: When ordering, please specify engine model and specification numbers. Discontinued OEM Kohler part # 230476-S.

Install snug-fitting neoprene rubber O-ring oil seal in YOUR governor cross shaft bushing. $5.00 for O-ring and labor, plus return shipping & handling.
Repair worn hole in YOUR governor cross shaft bushing with a new metal sleeve bushing and install snug-fitting neoprene rubber O-ring seal. $10.00 each for parts and labor, plus shipping & handling.
OUR used governor cross shaft bushing machined with snug-fitting rubber O-ring oil seal installed. $20.00 each, plus shipping & handling. (When available.)

Governor Cross Shaft Bushing with 7/32" hole. 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. OEM Kohler part # 41 158 02-S.

Install snug-fitting neoprene rubber O-ring oil seal in YOUR governor cross shaft bushing. $5.00 for O-ring and labor, plus return shipping & handling.
Repair worn hole in YOUR governor cross shaft bushing with a new metal sleeve bushing and install snug-fitting neoprene rubber O-ring seal. $10.00 each for parts and labor, plus shipping & handling.
New governor cross shaft bushing only. OEM Kohler part # 41 158 02-S. $8.05 each, plus shipping & handling.
New machined governor cross shaft bushing with snug-fitting rubber O-ring oil seal installed. $12.25 each, plus shipping & handling.

Governor Cross Shaft Bushing with 1/4" hole. Fits Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361. Discontinued OEM Kohler part # 235476-S.

Install rubber lip oil seal or snug-fitting neoprene rubber O-ring in YOUR governor cross shaft bushing. $5.00 for seal and labor, plus return shipping & handling.
Repair worn hole in YOUR governor cross shaft bushing with a new metal sleeve bushing and install rubber lip oil seal or snug-fitting neoprene rubber O-ring. $10.00 each for parts and labor, plus shipping & handling.
New rubber lip oil seal only (customer machines own bushing for installation of oil seal). $3.00 each, plus shipping & handling.
OUR used governor cross shaft bushing with rubber lip oil seal or snug-fitting neoprene rubber O-ring installed. $20.00 each, plus shipping & handling. (When available.)

Nylon Governor Gear Assemblies with Symmetrical Flyweights. Designed for general lawn and garden work. Also suitable for a 4,000± RPM competition pulling engine. Fits Kohler engine models K141, K160/K161, K181/M8, K241/M10, K301/M12, K321/M14, K341/M16, K361, KT17, KT17 Series II, KT19, KT19 Series II, MV16, M18, MV18, M20 and MV20. IMPORTANT: Due to high RPM and pressure of the governor gear upon engine start-up, before installing, lubricate the stub shaft and thrust washer with motor oil, automotive chassis lube or wheel bearing grease to prevent the governor gear from wearing until the crankcase oil reaches these areas.

Used and in excellent condition. $35.00 each, plus shipping & handling. (When available.)
New. OEM Kohler part # A-235743-S. $53.20 each, plus shipping & handling.

Nylon Governor Gear Assembly with Offset Flyweights. Recovers engine RPM quickly when under a load and maintains engine RPM at a more steady pace. Designed specifically for Kohler engine models K241/M10, K301/M12, K321/M14 and K341/M16 used with an air compressor, generator and/or welding unit. Ideal for use in a 4,000± RPM competition pulling engine. IMPORTANT: Due to high RPM and pressure of the governor gear upon engine start-up, before installing, lubricate the stub shaft and thrust washer with motor oil, automotive chassis lube or wheel bearing grease to prevent the governor gear from wearing until the crankcase oil reaches these areas.

New. OEM Kohler part # A-236294-S. $154.70 each, plus shipping & handling.

Cast Iron Governor Gear Assembly with Symmetrical Flyweights. Recommended for high RPM or wide open throttle competition pulling engines. Will not become distorted or explode at high RPMs or at wide open throttle like the nylon governor gears sometimes do. (Kohler never made a steel governor gear.) Fits Kohler engine models K141, K160/K161, K181/M8, K241/M10, K301/M12, K321/M14, K341/M16, KT17/KT17 Series II, KT19/KT19 Series II, MV16, M18, MV18, M20 and MV20. IMPORTANT: Due to high RPM and pressure of the governor gear upon engine start-up, before installing, lubricate the stub shaft and thrust washer with motor oil, automotive chassis lube or wheel bearing grease to prevent the governor gear from wearing until the crankcase oil reaches these areas.

Used and in excellent condition. Discontinued OEM Kohler part # A-237031-S. $75.00 each, plus shipping & handling. (When available. These are hard to find nowadays because not many were made.)

Governor Stop Pin. Fits all Kohler K-series and Magnum single- and twin-cylinder engines. 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.
Governor Cross Shaft End Bearing (Tiny Steel Bushing). Fits all early Kohler K-series single cylinder engines, except later K-series and all Magnum engines with machined blind hole in block for end of governor cross shaft. OEM Kohler part # 234866-S.

Used and in excellent condition. $3.00 each, plus shipping & handling. (When available.)
New. $5.35 each, plus shipping & handling.

Governor Linkages, Springs, Cables and Related Parts -

Throttle Link for Kohler engine model K90/K91 with .080" hole in governor and throttle levers. 1-5/8" overall length. OEM Kohler part # 220380-S. $11.61 each, plus shipping & handling.

Throttle Link for Kohler engine models K141, K160/K161, K181 and certain Magnum M8 with .080" hole in governor and throttle levers. 2-1/2" overall length. OEM Kohler part # 230078-S. $11.68 each, plus shipping & handling.

Nylon Bushing for throttle link used on Kohler engine models K181, M8, MV16, MV18, MV120 and certain aluminum block Kohler engines with 3/16" hole in governor and throttle levers. OEM Kohler part # 25 158 08-S. $1.49 each, plus shipping & handling.
Nylon Bushings for throttle link used on Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361 with Carter/Kohler #26, #28, #30 or Walbro WHG #52, #60, #64 carburetors with 3/16" hole in governor and throttle levers, and without ball integrated with throttle lever. Each also fits certain aluminum block Kohler engines with 3/16" hole in governor and throttle levers. The two bushings below are identical except for the color.

Black Bushing. OEM Kohler part # 25 158 11-S. $1.42 each, plus shipping & handling.
Translucent Bushing. OEM Kohler part # 47 158 07-S. $1.82 each, plus shipping & handling.

Throttle Link for Kohler Magnum engine model M8 with 3/16" hole in governor and throttle levers. 2-1/2" overall length. OEM Kohler part # 25 079 01-S. $4.53 each, plus shipping & handling.

New Style Throttle Link for Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361 with Carter/Kohler #26, #28, #30 or Walbro WHG #52, #60, #64 carburetors with 3/16" hole in governor and throttle levers. Not for ball integrated with throttle lever. 2-3/4" overall length. OEM Kohler part # 47 079 11-S. $2.79 each, plus shipping & handling.

New Style Throttle Linkage Kit for Kohler Magnum opposed (flathead) twin cylinder engine models KT17, KT17 Series II, KT19, KT19 Series II, M18 and M20 with 3/16" hole in governor and throttle levers. Includes two nylon bushings. Most commonly used linkage on these model engines.

OEM Kohler part # 52 079 11-S. $14.00 each, plus shipping & handling.

Throttle Linkage Push-On Retaining Nuts/Clips for Kohler engine models MV16, MV18, MV120 and certain aluminum block Kohler engines with .080" diameter throttle linkages. Discontinued from Kohler. Replaces Kohler part # 25 141 03-S. NOTE: These parts are very tiny. Use caution when handling.

$1.00 each, plus shipping & handling.

3/16" E-Clip (Retainer) for Early Style Throttle Rod (Linkage) used on Kohler engine models K241, K301, K330/K331, K321, K341 and K361 with early style throttle link/rod.

High quality aftermarket. .25¢ each, plus shipping & handling.
OEM Kohler part # 235278-S. $3.66 each, plus shipping & handling.

Early Style Throttle Rod (Linkage) for Kohler engine models K241, K301, K330/K331, K321, K341 and K361. OEM Kohler part # 235277-S.

Used and in excellent condition. $10.00 each, plus shipping & handling. (When available.)
New. $21.84 each, plus shipping & handling.

New 3/16" Throttle Ball Joint w/Integrated Ball/Threaded Stud for Kohler engine models K241, K301, K330/K331, K321, K341 and K361 with early style throttle link/rod. 10-32 UNF (fine thread) male and female threads. Fits Carter/Kohler #26, #28, #30 and Walbro WHG #52, #60, #64 carburetors without ball integrated with throttle lever. Can also be used on mini rods, hot rods, race cars, etc. 10-32 UNF (fine thread) male and female threads. NOTE: Apply motor oil inside ball joint to reduce wear and for smoother throttle operation.

High quality aftermarket. $5.00 each, plus shipping & handling.
OEM Kohler part # 237130-S. $15.55 each, plus shipping & handling.

Early Style Throttle Quick Disconnect/Snap-On Ball Joint Body for Kohler engine models K241, K301, K321, K341 and K361. Commonly used on K-series AQS (Quiet Line) engines. Fits Carter/Kohler #26, #28, #30 and Walbro WHG #52, #60, #64 carburetors with ball on throttle lever. Can also be used on mini rods, hot rods, race cars, etc. 10-32 UNF (fine thread) female threads and accepts 1/4" diameter ball. NOTE: Apply motor oil inside ball joint body to reduce wear and for smoother throttle operation. Discontinued from Kohler. Replaces Kohler part # 45 208 03-S.

High quality aftermarket. $8.50 each, plus shipping & handling.

Throttle Ball w/Threaded Stud for Quick Disconnect/Snap-On Ball Joint Body above È used on Kohler engine models K241, K301, K321, K341 and K361. . Fits Carter/Kohler #26, #28, #30 and Walbro WHG #52, #60, #64 carburetors with 3/16" hole in throttle lever. 1/4" diameter ball x 10-32 UNF (fine thread) threads. Includes nut and lock washer. Can also be used on mini rods, hot rods, race cars, etc. NOTE: Apply motor oil inside ball joint to reduce wear and for smoother throttle operation. Discontinued from Kohler. L Kohler part # 48 194 01-S. Replaced with Kohler part # 237130-S (ball joint w/integrated ball).

High quality aftermarket. $4.50 each, plus shipping & handling.

Quick Disconnect/Snap-On Throttle Ball Joint Assembly for Carter/Kohler and Walbro carburetors used on Kohler engine models K241, K301, K321, K341 and K361 with 3/16" hole in throttle lever. 10-32 UNF (fine thread) male and female threads. Fits Carter/Kohler #26, #28, #30 and Walbro WHG #52, #60, #64 carburetors without ball integrated with throttle lever. Can also be used on mini rods, hot rods, race cars, etc. NOTE: Apply motor oil inside ball joint body to reduce wear and for smoother throttle operation.

High quality aftermarket. $13.00 per assembly, plus shipping & handling.

Early Style Throttle Rod (Linkage) with Quick Disconnect/Snap-On Ball Joint and E-Clip Assembly for Kohler engine models K241, K301, K321, K341 and K361. Commonly used on K-series AQS (Quiet Line) engines. Assembled with Kohler part #'s 235277-S (rod), X-70-3 (nut), 45 208 03-S (ball joint body) and 235278-S (e-clip). Most parts discontinued from Kohler.

High quality aftermarket. $20.00 per assembly, plus shipping & handling.

Snap-On Throttle/Choke Cable Clip (Clamp). Use to secure throttle or choke cable conduit to extended OEM Kohler angled bracket on various Kohler engine models K141, K161, K181, K241, K301, K321, K341, M10, M12, M14, M16, K482, K532 and K582. OEM Kohler part # 235603-S. $4.80 each, plus shipping & handling.

Dual Conduit Throttle/Choke Cable Clamps. Can be used instead of clamp above for better security. Use to secure one or two 3/16" or 7/32" diameter cable conduit(s) to throttle or choke bracket. Each made of heavy gauge zinc-plated steel.

High quality aftermarket clamp only. Requires 3/16" mounting screw. Replaces Briggs and Stratton part #'s 22372 and 692179. $1.50 each, plus shipping & handling.
High quality aftermarket clamp with 3/16" screw, nut and split lock washer. Clamp replaces Briggs and Stratton part #'s 22372 and 692179. $2.00 each, plus shipping & handling.
Clamp only. Requires 3/16" mounting screw. OEM Briggs and Stratton part #'s 22372 and 692179. $3.00 each, plus shipping & handling.

Loop-Type Throttle/Choke Cable Clamps. Use to secure wire(s), battery cable, throttle or choke cable conduit, small fuel hose (for remote fuel primer) or bundle of wires along frame for safe routing. Each requires 3/16" mounting screw.

3/16" Loop Size. Our part # 03-249. $1.00 each, plus shipping & handling.
7/32" Loop Size. Our part # 03-2701. $1.00 each, plus shipping & handling.
Dual 7/32" Loop Size. OEM Kohler part # X-728-1-S. $1.38 each, plus shipping & handling.

Throttle Wire/Stranded Cable Swivel Kits. Use to secure solid throttle wire to speed control bracket for a stock/governed engine or to secure stranded throttle cable to throttle lever on carburetor for a competition pulling engine. Each kit includes wire swivel, screw and friction washer, and require a 15/64" / 6mm hole.

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 Brackets. Each fits various 10-16hp Kohler engines, depending on application.

Bracket without adjustment yoke. OEM Kohler part # 235086-S. $4.25 each, plus shipping & handling.
Bracket with adjustment yoke. OEM Kohler part # 236413-S. $10.05 each, plus shipping & handling.

Throttle Stabilizer/Anti-Surge Springs. Lightweight spring connects between throttle and governor levers to remove free play (looseness) in linkage connections and reduce erratic engine behavior due to throttle flutter for a smoother running engine and reduce wear to throttle shaft. Can be used on virtually any Briggs & Stratton, Kohler K-series, Magnum or Command single- or twin-cylinder cast iron or aluminum block engine. A must for a generator, welder or 4,000 RPM± governed competition pulling engine. With a governed pulling engine, throttle flutter causes the engine RPM to momentarily spike, which will cause the rear tires to lose traction (temporary jerk), resulting in a possible failed pull. If a small hole isn't already present in each lever close to linkage connection, may need to drill a small hole to install spring.

2-7/16" overall length. High Quality Aftermarket Throttle Stabilizer/Anti-Surge Spring. $5.00 each, plus shipping & handling.
2-1/8" overall length. OEM Kohler part # 230117-S. $8.23 each, plus shipping & handling.
4-1/8" overall length. OEM Briggs & Stratton part #'s 260478, 690545. $9.00 each, plus shipping & handling.

V-Shaped/Coiled Governor Springs to regulate and maintain engine speed. Each has hook on each end.

Designed for various Kohler engine models K141, K160/K161, K181 and M8 used for general lawn and garden use. OEM Kohler part # 232617-S. $7.20 each, plus shipping & handling.
Designed specifically for Kohler engine model K181 used with a generator. OEM Kohler part # 232619-S. $15.80 each, plus shipping & handling.

V-Shaped/Coiled Governor Spring to regulate and maintain engine speed. Designed for various Kohler engine models K181 and M8. Has hook on one end and "Z" bend on other end.

OEM Kohler part # 41 091 02-S. $21.91 each, plus shipping & handling.

Governor Spring to regulate and maintain engine speed. Designed for newer Kohler engine model K181's with specification numbers 301000-301045, and various Kohler Magnum engine model M8's with specification numbers 301500-301651.

OEM Kohler part # 41 089 12-S. $7.60 each, plus shipping & handling.

26 Coil Governor Spring to regulate and maintain engine speed. Designed for most Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361. Used in Cub Cadet models: 70, 71, 72, 73, 86, 100, 102, 104, 105, 106, 107, 108, 109, 122, 123, 124, 125, 126, 127, 128, 129, 149, 169, 1050, 1204, 1210 and 1211. Also can be used on various Kohler engine models KT17, KT17 Series II, KT19, KT19 Series II, M18 and M20. All these engines listed use the same governor gear assembly. 2-5/8" overall length (outside hook to outside hook). Replaces discontinued 23 coil governor spring, Kohler part # 45 091 01-S.

OEM Kohler part # 235496-S. $11.50 each, plus shipping & handling.

26 Coil Extended Length Governor Spring to regulate and maintain engine speed. Designed for various Kohler K-series and Magnum engine models with the following specification numbers: K301-47766, K341-71207, 71209, 71232; M10-461504, 461505, 461512, 461513, 461526, 461530, 461531, 461532, 461539, 461542, 461543, 461546, 461551; M12-471504, 471505, 471506, 471507, 471553, 471554, 471555, 471569, 471571 471572, 471576, 471583, 471585, 471589; M14-601504, 601505, 601553; M16-711504, 711505, 711506, 711507, 711534, 711535, 711551, 711552, 711558, 711577, 711585. Used with an air compressor, concrete saw or sprayer. 5-5/8" overall length (outside hook to outside hook). Replaces discontinued 23 coil extended length governor spring, Kohler part # 47 089 07-S.

OEM Kohler part # 47 089 09-S. $6.25 each, plus shipping & handling.

34 Coil Extended Length Governor Spring to regulate and maintain engine speed. Designed for Kohler K-series AQS (Quiet Line) and Magnum engine models with the following specification numbers: K241-46717, 46720, 46734, 46740, 46753, 46754, 46763, 46785; K301-47541, 47542, 47581, 47585, 47606, 47620, 47634, 47640, 47643, 47673, 47732, 47764, 47795, 47805; K321-60244, 60269, 60270, 60291, 60293, 60311, 60312, 60318, 60320, 60321, 60343, 60374, 60397, 60402, 60411, 60413, 60415; K341-71147, 71148, 71164, 71167, 71169, 71172 71176, 71198, 71203, 71221, 71222, 71227, 71242, 71243, 71270, 71275, 71338, 71355, 71356, 71366, 71369; M10-461509, 461521, 461533, M12-471514; 471516, 471527, 471528, 471536, 471538, 471545, 471546, 471549, 471580, 471581, 471584; M14-601513, 601524, 601525, 601528, 601534, 601538, 601540, 601542, 601558, 601559, 601561; M16-711513, 711514, 711521, 711523, 711527, 711528, 711529, 711532, 711536, 711537, 711539, 711544, 711546, 711555, 711560, 711562, 711563, 711568, 711570, 711575, 711576, 711580, 711593. Used in Cub Cadet models: 680, 1000, 1200, 1210, 1250, 1282, 1450, 1650, and John Deere AQS (Quiet Line) engines. Most common for general lawn and garden use. 8" overall length (outside hook to outside hook).

OEM Kohler part # 47 091 01-S. $13.25 each, plus shipping & handling.

Universal-Fit Replacement Choke or Throttle Control Knob/Handle. Made of durable plastic. Replace missing knob/handle for more comfortable operation of the in-dash or panel-mounted choke or throttle cable control. 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 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". Our 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 tractors Cub Cadet garden tractors Cub Cadet 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". Our 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 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". Our 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". Our 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 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: 580, 582, 1604 and 1606. OEM Cub Cadet part # 746-3004. Discontinued from Cub Cadet and not available in aftermarket.

Universal High Quality Foot/Gas Pedal Kit. Can be used on Competition Pulling Tractors, Go-Karts, Recreational Vehicles, etc. Kit includes 48" (commonly used) sliding stranded inner cable x 43" metal conduit housing and housing clamp. $46.00 each, plus shipping & handling.
Heavy Duty High Quality Replacement Throttle Control Cable Assemblies for Universal Foot/Gas Throttle Pedal Assembly.

48" inner stranded wire cable x 43" metal conduit housing. $5.00 each, plus shipping & handling.
53" inner stranded wire cable x 48" metal conduit housing. $5.00 each, plus shipping & handling.
60" inner stranded wire cable x 55" metal conduit housing. $5.00 each, plus shipping & handling.
100" inner stranded wire cable x 90" metal conduit housing. $7.50 each, plus shipping & handling.

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

For a fancy and noticeable gas pedal, install a chrome-plated, die-cast aluminum "barefoot" pedal. These were popular in the late '60s to early '70s as a nostalgic item used mainly on street rod and hot rod vehicles. They're available on eBay. Use a medium size household brass door hinge to fasten the pedal to the foot rest on 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 sliding solid wire throttle control, the driver must quickly reach for the throttle lever to idle down the engine. Many pulling association's/club's rules 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.

Sliding Cable Spring-Return Throttle Control Setup for 10-16hp 4,000 RPM governed Kohler Competition Pulling Engines - (Added 7/27/18)

To fabricate a sliding cable spring-return throttle control setup for a 4,000 RPM governed 10-16hp Kohler competition pulling engine or recreational 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 throttle control 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 cable.

When using the sliding stranded cable housing to operate the throttle control, in order for the inner cable to slide back and forth with less friction inside the housing, pull the cable from the housing (with one end [ball] cut off), and 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 inserting the cable in the housing, singe the end of the cable with a propane or oxy-acetylene torch (with a small, blue flame) to bind the strand of wires together to prevent the end of the cable from unraveling, and then grind down the lump of molten metal so the cable can be easily inserted in the housing and in the wire swivel clamp. Also, being most new stranded sliding cable assemblies come with no lubricant inside the housing, it'll be a good idea to remove the inner cable from the housing, and use the 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. An ingenious and innovative idea by Brian Miller.

And the reason a throttle foot pedal is more common than a hand-operated throttle lever on pulling tractors is because both hands are needed on the steering wheel to have full control of the tractor as a safety precaution while it's going down the track.

Oh, and if you've ever wondered what a "dead man's throttle" is, it's a spring-loaded foot throttle 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.

Fabricate a Sliding Stranded Throttle Cable Control Setup for K241-K341 Kohler Engines | [Top of Page]

Professional Remote Spring-Return Cable-Operated Foot Pedal Throttle Control Setup for 4,000 RPM Governed Stock Competition Pulling Tractors, Go-Karts, Recreational Vehicles, Snowmobiles, King Midget micro cars (Kohler engines in King Midget cars originally come from the factory with no governor components; governor components must be installed in engine for this kit to work), etc. with a 10-16hp Kohler engine. If governored RPMs is set correctly (3,600 or 4,000 maximum), this setup will prevent over-revving of the engine, which could cause connecting rod breakage, and possibly damage or destroy the engine block. An ingenious and innovative concept by Brian Miller.

This proven and well thought-out design below allows the sliding stranded cable to be connected to the carburetor from the exhaust end of the engine, with the cable housing mounted well above the hot header pipe. This design places a lot less pressure and friction on the throttle shaft/bushing to reduce wear. Return To Previous Paragraph or Section

How to Limit the RPM and Safely Operate Virtually Any Small Engine Without a Working Governor - (Updated 12/21/20) [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 engines were designed for a specific lightweight vehicle, such as for a go-kart, recreational vehicle, snowmobile or King Midget micro car. Kohler K301 engines in snowmobiles and King Midget cars originally come from the factory with no governor components. Kohler engine models that came from the factory with no governor components has the following specification numbers: K241-46202, 46254, 46393, 46447; and K301-4743, 4751, 47103, 47119, 47127. There's also a Kohler engine model K91-31503 installed on equipment manufactured by J. Luekart Machine that did not come with any governor components. Anyway, being there's no governor to automatically open the throttle when the engine is under a severe load, this type of engine can't be used where a lot of lugging power is required. You would think that when the engine isn't under a load, it will rev at wide open throttle and throw the rod. But here's how the RPMs are limited: On a Kohler engine without a governor, the camshaft is advanced by one tooth in relationship to the crankshaft. Advancing the camshaft opens the valves sooner than usual. This allows the engine to run at a much lower compression. Therefore, due to the very low operating compression, it will not be able to rev above 3,200 RPM±.

As a matter of fact, this was done by Tecumseh Engine with a certain older (mid 1970's) Sears Craftsman Eager 1 walk-behind or self-propelled lawn mower engines that has no governor components. Certain other mid-1970's Sears Craftsman Eager 1 walk-behind or self-propelled lawn mower engines has either a very low compression cylinder head with a huge combustion chamber, which limited the RPMs to 3,200±; and other mid-1970's Sears Craftsman Eager 1 walk-behind or self-propelled lawn mower engines with no governor has an ordinary cylinder head with an extremely small diameter carburetor throttle bore and intake extension tube that reduced the velocity of air/fuel the engine can draw in, which limited the RPMs to 3,200±). (Incidentally, this works the same as the restrictor plate for certain racing go-kart and NASCAR classes.) And certain other mid-1970's Sears Craftsman Eager 1 walk-behind or self-propelled lawn mower engines has an ordinary cylinder head and ordinary size carburetor/intake extension tube, but the camshaft was advanced by one tooth, which limited the RPMs to 3,200±. These are all proven methods to limit the engine RPMs and works very well. Personally, back in the day (early 1980's), I've had all of these Sears Craftsman Eager 1 engines in my shop brought to me by customers for a tune-up or repairs. These apparently are rare engines. If they were not in my shop, I would not have known that they existed. - Brian Miller

To safely run an engine without a working governor at a reasonable RPM, the camshaft will need to be advanced (BTDC) by one tooth in relationship with the crankshaft. Doing this lowers the compression pressure in the combustion chamber dramatically, preventing the engine from accelerating to its full potential at wide open throttle. The automatic compression release (only on the Kohler single cylinder engines) will not be required on the camshaft. At wide open throttle, the engine will rev to only around 3,200 RPM, and no more. The engine should start quickly and should produce plenty of power when under a load. But with the camshaft advanced one tooth, when using camshaft-operated ignition points, this would also advance the ignition timing way too far. Regarding the Kohler engine, being the ignition points operate off the cam and being the camshaft is advanced one tooth, the ignition timing will be far too advanced for the engine to start and run. Therefore, for the timing to be set at 20º BTDC, the engine will need to have either a magneto, Breakerless or solid state (Magnum) ignition system, which are all triggered off the flywheel, or a crank trigger ignition system, which is triggered off the flywheel or crankshaft.

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 a go-kart, recreational vehicle, snowmobile, King Midget micro car, 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 Wide Open Throttle With No Operating Governor - (added 5/23/15

On a pulling engine that pulls at wide open throttle, 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.

IMPORTANT! 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 high RPM or at wide open throttle 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 high RPM or at wide open throttle. 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.
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 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 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 high RPM or at wide open throttle). 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.

Don't Be a Slob When Rebuilding an Engine!

Older cast iron block Kohler engines are like old 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.

You can also use an automotive engine stand to rebuild a Kohler engine. Just use the two starter bolt holes 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 club's rules 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.

IMPORTANT! 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 end-play/clearances 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.

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 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 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 RPMs. 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 RPMs.

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/M12 crankshaft is different from the 14 and 16hp cranks because the counter weights are machined off for the lighter-weight K301/M12 piston assembly. NOTE: Some 10hp cranks also have the counter weights machined off like the K301/M12 does, but 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 -

Remove the flywheel and anything that's on the PTO end of the crankshaft.
Remove the cylinder head.
Remove the oil pan.
Remove the piston/connecting rod assembly from the engine block.
Remove the bearing plate.
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.
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 club's rules 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.

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...

Make sure the grinding stone is precision balanced, then true it up so it won't leave skip marks on the journal.
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.
If it's a multiple journal crankshaft, perform the above È with the crankshaft firmly clamped in both chucks.
Firmly tighten the chuck(s).
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.
Set up the dial indicator, and position it's lever on the #1 journal.
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.
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.
If it's a multiple journal crankshaft, position the steady rest in the center main journal to prevent flexing of the crankshaft when grinding.
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.
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.

IMPORTANT! The standard (STD) size rod journal (crank pin) on Kohler's K241/M10, K301/M12, K321/M14 and K341/M16 flatheads, K361 and the M20, MV20 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 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 high RPM or at wide open throttle 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 high RPM or at wide open throttle.

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.

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 performance valve job to increase the air flow and milling of the head will help the engine to pump out a few more ponies, too.

About Crankshafts Breaking at High RPM or at Wide Open Throttle -

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 (steel flywheels should be precision-balanced, too); 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 high RPM or at wide open throttle. 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. I heard that the Magnum crankshafts are tougher than the early K-series cranks when precision-balanced. And when a crankshaft breaks at high RPM or at wide open throttle, 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 Professionally Clean Engine and Associated Parts -

DANGER! IMPORTANT! NEVER USE GASOLINE OR ANY HIGHLY FLAMMABLE LIQUID TO CLEAN PARTS! Gas cleans good, 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 coating on parts that will not dry out, and they 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. Paint thinner and mineral spirits are non-oily. These dry out with no signs of it ever being on the part. FYI - Most [high dollar] commercial engine parts cleaning solvents is just paint thinner or mineral spirits with an added odor and/or colored dye. Personally, I've always used the 100% paint thinner purchased at Walmart to clean my own and my customer's engines, transmissions and other parts. Although paint thinner and mineral spirits can burn too, they has about the same flash point as some popular brands of charcoal starter fluid. So don't use these near open flames and don't smoke while using either one. For safety and convenience, use a professional parts washer machine to clean parts.

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 a Cast Iron Engine Block or Cylinder Head -

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!

Or use a heavy duty bathroom toilet bowl cleaner. Most of them 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. I 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.

How to Get More Power Out of a Stock Engine -

It takes three things to make an internal combustion engine run: compression, carburetion and ignition. There's three things that make an internal combustion engine run: Carburetion, compression and ignition. Fuel needs to get to the carburetor and then into the engine. The engine needs to have adequate compression to fully compress the air/fuel mixture to make power. 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 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 start or if it's hard to start, 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:
ü Carburetion is when an adequate amount of fuel and air mixture enters an engine smoothly.
ü 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.
ü 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.
ü Another way to gain more power from the high RPM is to install a special camshaft along with larger diameter valves, performance valve job, stiffer valve springs and enlarge intake and exhaust port runners.
ü 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.
ü 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 the valves are reworked for more airflow, 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 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 the majority of the fins are removed from the flywheel, or if a steel flywheel is used, this will add about 3-4 more hp at 4,000 RPM per 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!

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. I 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 and Stratton, Tecumseh, Onan and Kohler's cast iron block 7hp and 8hp, and the 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.

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/M10 Kohler engine in a class that allow up to a K301/M12 engine, there's no need to go out and acquire a K301/M12 block, and then have all the fancy machine work that was originally done on the 10hp block. Instead, a 10 can be easily converted into a 12 by having the cylinder bored for a K301/M12 piston assembly, a 12, 14, 16 or 18hp connecting rod, and a K301/M12 crankshaft.

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/M12 piston (even up to .040" oversize), without making the cylinder wall too thin. They cannot be bored for a K321/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.

The K301 blocks with a 10hp bore can be safely bored for use with a K301/M12 piston. The K301 blocks are actually a K301/M12 block with a 10hp bore. There's nothing special about this blocks, except for the thicker cylinder wall. They weren't used in any "heavy duty" specific purpose either. What happened is on the production line at Kohler, when they ran out of 10hp blocks, they grabbed a bunch of K301/M12 blocks and bored them for use with a 10hp piston to finish the production of a bunch of 10hp engines. And not all Kohler blocks that have the K301 characters are actually 10hp blocks. Some are bored for a K301/M12 piston assembly (3.375" STD size bore) and therefore, are a K301/M12 block. The ones that are bored for a 10hp piston assembly (3.250" STD size bore) have a thicker cylinder wall and therefore, are a 10hp block. To determine which block is which, the diameter of the cylinder bore needs to be accurately measured.

How to Create a 27 CID Hybrid Kohler Engine Model K271 (Stroker K241/M10 Engine) - An ingenious and innovative concept by Brian Miller, because nobody else mentions this online.
To create a 27 CID hybrid Kohler engine model K271 (Stroker 10hp), the parts to use are:

K241/M10 block.
K241/M10 piston/rings assembly.
K301/M12, K321/M14, K341/M16 stock connecting rod, or a 5.7" billet rod with a 1.500" plain aluminum journal hole.
K301/M12, K321/M14, K341/M16 or K361 crankshaft.

This combination of parts will create a 27 cubic inch engine, or hybrid model K271, or a "stroker 10hp engine." With a STD size [10hp] piston, this engine will have a 3.250" bore and 3.250" stroke, resulting in a 26.96 cubic inch displacement engine. For strength and durability, especially if it's built to the max, it's best to use a model K241 block with K301 embossed on the PTO end, like the one pictured above È. These particular blocks have an extra thick cylinder wall.
If this engine is built to the max at 4,000 RPM with reworked stock size valves, ported, quality performance torque cam and a bored-out and reworked 1.2" carburetor, it'll produce about 19hp and 25 ft. lb. of torque at 4,000 RPM. But if built to the max at wide open throttle with reworked stock size valves, ported, big performance cam and bored-out 1.2" and reworked carburetor, it'll produce about 29hp at 7,000 RPM and 22 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 .080" offset toward the oil dipper so the piston will come flush with the top of the block, or it can be bored .100" offset toward the oil dipper for a .020" piston pop-out. 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 area, 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 piston will need to be enlarged to exactly .8755" for use with the 12, 14, 16hp flathead or 18hp OHV ALCOA rod's wrist pin, or the wrist pin hole in the rod can be reduced with a bronze bushing I.D. of .8594" (55/64") for use with the 10hp piston's wrist pin.
IMPORTANT! Being a heavier crankshaft 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 subtracted from the counterweights on the crankshaft so the rotating assembly will be properly balanced. Click here to learn how to statically balance an engine.
The lower sides of the cylinder wall may need to be clearanced (ground away) for the connecting rod due to the longer stroke.
Set the ignition timing as usual, at 20º BTDC.
Giving an engine a longer stroke will gain an edge over the competition. Click or tap here for an explanation of why a longer stroke works better.
If building this type of engine for competition pulling, check your club's sanctioning rules so this engine will be legal within its class!

How to Create a 25.7, 27.7, 31.6 CID Hybrid Kohler Engine Model K261, K281 or K321 - An ingenious and innovative concept by Brian Miller, because nobody else mentions this online.
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, or K341/M16 engine block.
K301/M12, K321/M14, or K341/M16 piston/rings assembly.
Stock K241/M10 connecting rod, or a 5.558" billet rod with a 1.500" plain aluminum hole.
K241/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/M12 block; the K281 will use a K321/M14 block, and the K321 will use a K341/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 with reworked stock size valves, ported, quality performance torque cam and a bored-out and reworked 1.2" carburetor, it'll produce about 16½hp and 23 ft. lb. of torque at 4,000 RPM. And if built to the max at wide open throttle with reworked stock size valves, 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 reworked 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 wide open throttle with reworked stock size valves, 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 reworked stock size valves, 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 wide open throttle with reworked 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/M10 rod will need to be enlarged to exactly .8755" for use with the K301/M12, K321/M14 or 16hp piston's wrist pin.
IMPORTANT! 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/M10 crankshaft so the rotating assembly will be properly balanced. 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 club's sanctioning rules 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 - An ingenious and innovative concept by Brian Miller, because nobody else mentions this online.
This is considered "old school technology" by today's standards, but it still works great when club's Stock engine pulling rules 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.
IMPORTANT! If this type of engine is operated at high RPM or at wide open throttle, even with the rotating assembly precision and dynamically spin-balanced, due to the heavier-than-stock Chevy piston assembly, the connecting rod could stretch and/or the crankshaft could break. Therefore, with the rotating assembly precision and dynamically spin-balanced, it's best to limit the RPMs at 4,000 and no higher. Anyway, the correct parts to use are:

A 12 (or 13) fin K341/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/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") OEM-type piston, rings and wrist pin.
Use an OEM Kohler K341/M16 16hp "new style" (thicker beam) connecting rod. Kohler's "new style" rod has a thicker beam section than other Kohler rods, which makes it just as strong as a billet rod. Bearing inserts must be 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/M12 crankshaft, which would require A LOT MORE ballast weight for balancing.
The K341/M16 engines have a STD bore of 3.750". With the 3-7/8" 307 piston, it'll have a 1/8" overbore. And with the 4" 327 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/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 reworked stock size valves, 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 reworked stock size valves, 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.) IMPORTANT! 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.)
IMPORTANT! 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. IMPORTANT! 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 club's sanctioning rules 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 newer K301/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.
IMPORTANT! 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 pictured 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.
IMPORTANT! 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 RPMs. Due to the small bore and long stroke, this combination produces more torque (lugging power) at high RPM or at wide open throttle than building a K301/M12 block 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 high RPM or at wide open throttle, 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 and K321/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 K341 K-series and M16 Magnum 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 and K321/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.

IMPORTANT! Do not attempt doing the above È on the 10hp, K301/M12 or K321/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 Julian Stahl.

Why a Longer-Than-Stock Stroke Works Better For 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 high RPM or at wide open throttle, 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 high RPM or at wide open throttle, 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 K241/M10 (10hp) and K301/M12 (12hp) Kohler engines. Unlike a healthy 10hp, a K301/M12 in good condition that's in a garden tractor will literally "pull you back in the seat" when the engine is accelerated quickly. This is what engine torque does. The powerful acceleration is because not only the 12hp has an 1/8" larger bore than the 10hp, but it has a much longer crankshaft stroke, 3/8" longer to be exact. Plus, the 12hp engine has higher compression ratio than the 10hp. 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 because the 12hp use the same cylinder head with the same size combustion chamber as the 10hp. But there's not really that much of a noticeable difference in power and torque between a 12hp and a 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. Another example is the 7hp and 8hp Kohler engines. These are virtually identical in every way except for the length of the stroke. The 7hp has a stroke of 2.500", and the 8hp's stroke is 2.750". A 1/4" longer stroke (and higher compression due to the same cylinder head) results in 1hp more. The Kohler twin cylinder engine, KT17/M16/M18/MV18 (which are basically made identical) has a stroke of 2.750", and the KT19/M20/MV20 (which are basically made identical) engine's 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 gives the bigger engines (KT19/M20/MV20) 2 more horsepower. Many new automotive engines in heavier vehicles nowadays (mainly trucks) have a small bore and long stroke. (Remember Ford's "Power Stroke" engine? Simply because it works better for hauling heavy loads at higher RPMs!) Return to previous paragraph È

If your club's rules 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 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/M10 block can be bored to use a K301/M12 piston and a 12 hp block be bored to use a K321/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/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 10hp block bored for a K301/M12 piston, or a K301/M12 block bored for a 14hp piston, and you use your tractor to push snow, definitely fasten 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. I 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 engine. They'll produce more horsepower and torque per cubic inch than any flathead engine ever will.

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

"Strapping" the cylinder to the crankcase is when a flat piece of heavy steel or aluminum is across the cylinder head and fastened by means of two 1/2" diameter threaded rods, one located just behind the flywheel and the other on the PTO end of the block. It keeps the cylinder from literately breaking loose from the crankcase because of a thin cylinder wall due to the installation of an excessively oversize piston and a big cam, which produce extremely high compression at wide open throttle. Position the strap directly over (center of) the cylinder and not between the piston and valves, or over the valve area. Only one strap is sufficient. There's no need to install two straps.

There's no need to install long threaded rods (All Thread) directly into the block to fabricate a head/cylinder restraint setup to fasten the cylinder to the crankcase. And NEVER install long threaded rods for the restraint system in the top edge of the OEM Kohler 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 picture 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 Kohler large bearing plate (for the gear starter). With a small bearing plate however, the ridges will need to be ground away for clearance of the brace. And the other "T" brace is fastened on the PTO end of the block with a couple of 3/8" bolts. If there's no bolt holes, two 3/8" threaded holes will need to be made for mounting of the brace. Then measure, cut off, and align the threaded rods, and weld them to the "T' braces. Torque the strapping nuts to 10 ft. lb. each. Return To Previous Paragraph

Advertisement: (posted 5/26/15)

If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

Cylinder Restraint Strap Kit for Kohler 10-16hp K-series and Magnum Engines. This setup is easy to remove and reinstall when it comes time to freshen the engine. It looks nice and very strong. Prevents cylinder/crankcase separation (engine explosion) during cool weather when cylinder is bored thin for an excessively oversize piston. A must for methanol-burning engines. Professionally made by Brian Miller. NOTE: An additional 3/8" threaded hole may need to be made for mounting of brace on PTO end of block.

A-1 Miller part. $45.00 per kit, plus shipping & handling.

A K301/M12 block definitely can't be bored for use with a 16hp piston because the outside diameter of the cylinder wall is too small. And it's doubtful that a K321/M14 block can be bored for use with a K341/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 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:

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.)
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!
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.
Chamfer or bevel the outside lower end of the sleeve for easier installation in the cylinder.
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.
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.
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.
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.

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, K181/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 warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities and 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 cleaner 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 RPMs.

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 PCV (Positive Crankcase Ventilation) 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 RPMs. 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.

Use an Auxiliary Crankcase Breather Setup for Better Crankcase Venting at High RPM or at Wide Open Throttle -

The factory OEM crankcase breather alone isn't sufficient enough for all high performance single cylinder engines, especially big cubic inch engines running at high RPM or at wide open throttle. 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 high RPM or at wide open throttle, 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 high RPM or at wide open throttle, 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 high RPM or at wide open throttle, 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 picture 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 high RPM or at wide open throttle, 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 expansion/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 expansion/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 -

IMPORTANT! 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 high RPM or at wide open throttle. 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 clean motor oil, gear oil or lubricating grease inside the camshaft and on the cam pin to prevent [most likely] engine seizure just after starting and running for a few minutes!

Performing a Compression Test on a Stock or High Performance Small Engine with a Compression Tester -

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, KT17 Series II, KT19, KT19 Series II, 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, K181/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/M10 engines can range from 98 to 150 PSI. On the K301/M12 engines, it can range from 112 to 170 PSI. On the K321/M14 engines, it can range from 120 to 190 PSI. The K341/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.

When installing the piston and rings in the cylinder, the K241/M10, K301/M12 and K321/M14 Kohler pistons installs either way because the wrist pin is centered in the piston. But if the [OEM] piston has a notch, such as the K341/M16 and K361 18hp OHV engine pistons, these install with the notch facing toward the flywheel end of the block. And to lessen the chance of blow-by, don't forget to offset or stagger the ring end gaps 120º-180º. Then use a quality-made piston ring compressor tool or if a ring compressor isn't available, a ring compressor can be fabricated out of clean (no paint, rust, etc.) 2" x 14" x 16 gauge steel sheet metal (heating duct tin works excellent) with a large adjustable radiator hose clamp to compress the rings. 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 installs toward the flywheel end 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 make more cubic inches without enlarging the crankcase 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 have the wrist pin centered. These pistons can be installed in either direction.

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 high RPM or at wide open throttle.

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 quality 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 clean motor oil, gear oil or lubricating 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:

The bottom ring [set] (oil lubricator) and expander, if used, goes on first.
The middle ring (oil scraper) and expander, if used, goes on second.
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 water- and air-cooled engines, being a small engine, automotive, diesel, airplane, etc.)

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.
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.
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.
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:

Worn piston, resulting in worn rings. Solution: Rebuild engine with a new piston and rings.
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.
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.
Leaking crankshaft oil seal. Solution: Install new oil seal with oil grease on rubber lip to prevent premature wear.
Small air gap between the two crankcase halves where it wasn't sealed properly with silicone. (Kohler opposed twin cylinder engine models KT17, KT17 Series II, KT19, KT19 Series II, MV16, M18, MV18, M20 or MV20 only.) Solution: Split crankcase and reseal entire circumference of crankcase halves with a thin bead of RTV silicone 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 (paint thinner), 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. "Metal flake looks good in paint, not in oil."

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.

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.

IMPORTANT! 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 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 measured again. If it measures too small, it will need to be honed to the final 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 and in a cool or cold environment.

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If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

NOTE: All parts listed here are NEW, unless otherwise stated. I 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 and Stratton part #'s 294232, 295657 (3hp), and Clinton part #'s 233112500, 233122500.

High quality aftermarket. Same 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" Oversize Ring Set Only. Fits K90/K91 engines with 2.385" cylinder bore. OEM Kohler part # 220802-S. Also replaces Briggs and Stratton part # 294224 (NLA). $64.00 per set, plus shipping & handling.
.010" 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" Oversize Ring Set Only. Fits K90/K91 engines with 2.395" cylinder bore. OEM Briggs and 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" Oversize Ring Sets Only. Fits K90/K91 engines with 2.405" cylinder bore.

OEM Briggs and Stratton part # 294226. $60.00 per set, plus shipping & handling.
OEM Kohler part # 220804-S. $81.80 per set, plus shipping & handling.

.030" 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 and early K161 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). These are for the small 2-7/8" size cylinder bore. Cylinder can be bored to 2-15/16", and the bigger piston and rings 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. Fits K141, K160 and early K161 engines with 2.875" cylinder bore. Discontinued OEM Kohler part # 231424-S. $48.00 per set,plus shipping & handling. (New Old Stock - When available.)
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. $153.90 each, plus shipping & handling.
.010" Oversize Ring Set Only (2.885" cylinder bore. OEM Kohler part # 231425-S. $79.80 per set,plus shipping & handling.
.010" Oversize Piston and Ring Set. Fits K141, K160 and early K161 engines with 2.885" cylinder bore. OEM Kohler part # 41 874 02-S. Discontinued from Kohler. L
.020" Oversize Ring Set Only. Fits K141, K160 and early K161 engines with 2.895" cylinder bore. OEM Kohler part # 231426-S. $82.35 per set,plus shipping & handling.
.020" Oversize Piston and Ring Set. Fits K141, K160 and early K161 engines with 2.895" cylinder bore. OEM Kohler part # 41 874 03-S. $197.80 each, plus shipping & handling.
.030" Oversize Ring Set Only. Fits K141, K160 and early K161 engines with 2.905" cylinder bore. OEM Kohler part # 231427-S. $82.35 per set,plus shipping & handling.
.030" Oversize Piston and Ring Set. Fits K141, K160 and early K161 engines with 2.905" cylinder bore. OEM Kohler part # 41 874 04-S. Discontinued from Kohler. L

Kohler K-series and Magnum engine models K141, K160/K161, K181 and M8 Ring Sets, and Piston and Ring Sets (includes wrist pin and retaining clips). These are for the bigger 2-15/16" size cylinder bore. 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 K141, K160/K161, K181 and M8 engines with 2.938" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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 and Ring Sets. Fits K141, K160/K161, K181 and M8 engines with 2.938" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 41 874 05-S. $44.00 each, plus shipping & handling.
K-series cast piston and 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 and Ring Sets. Fits K141, K160/K161, K181 and M8 engines with 2.941" cylinder bore.

K-series cast piston and 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" Oversize Ring Sets Only. Fits K141, K160/K161, K181 and M8 engines with 2.948" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K141, K160/K161, K181 and M8 engines with 2.948" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 41 874 07-S. $40.00 each, plus shipping & handling.
K-series cast piston and 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" Oversize Ring Sets Only. Fits K141, K160/K161, K181 and M8 engines with 2.958" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K141, K160/K161, K181 and M8 engines with 2.958" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 41 874 08-S. $50.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 41 874 08-S. $193.45 each, plus shipping & handling.
Mahle piston and rings. OEM Kohler part # 41 874 13-S. Discontinued from Kohler. L

.030" Oversize Ring Sets Only. Fits K141, K160/K161, K181 and M8 engines with 2.968" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K141, K160/K161, K181 and M8 engines with 2.968" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 41 874 09-S. $41.00 each, plus shipping & handling.
K-series cast piston and 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 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 and Ring Sets. Fits K241, M10 and K482 engines with 3.250" cylinder bore.

High quality aftermarket. Same 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" Oversize Ring Sets Only. Fits K241, M10 and K482 engines with 3.260" cylinder bore.

High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K241, M10 and K482 engines with 3.260" cylinder bore.

High quality aftermarket. Same quality as OEM Kohler part # 47 874 03-S. $32.00 each, plus shipping & handling.
OEM Kohler part # 47 874 03-S. $216.00 each, plus shipping & handling.

.020" Oversize Ring Sets Only. Fits K241, M10 and K482 engines with 3.270" cylinder bore.

High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K241, M10 and K482 engines with 3.270" cylinder bore.

High quality aftermarket. Same 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" Oversize Ring Sets Only. Fits K241, M10 and K482 engines with 3.280" cylinder bore.

High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K241, M10 and K482 engines with 3.280" cylinder bore.

High quality aftermarket. Same 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/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 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. $82.17 per set, plus shipping & handling.

STD Size Pistons and Ring Sets. Fits K301, M12 and K532 engines with 3.375" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 06-S and 48 874 01-S. $39.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 47 874 06-S. $184.44 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 48 874 01-S. $288.99 each, plus shipping & handling.
Mahle piston and rings. OEM Kohler part # 47 874 16-S. Discontinued from Kohler. L

.003" Oversize Piston and Ring Set. Fits K301, M12 and K532 engines with 3.378" cylinder bore. Mahle piston and rings. OEM Kohler part # 47 874 17-S. Discontinued from Kohler. L
.010" Oversize Ring Sets Only. Fits K301, M12 and K532 engines with 3.385" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K301, M12 and K532 engines with 3.385" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 08-S and 48 874 03-S. $45.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 47 874 08-S. $247.81 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 48 874 03-S. $228.89 each, plus shipping & handling.
Mahle piston and rings. OEM Kohler part # 47 874 18-S. Discontinued from Kohler. L

.020" Oversize Ring Sets Only. Fits K301, M12 and K532 engines with 3.395" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K301, M12 and K532 engines with 3.395" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 09-S and 48 874 04-S. $46.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 47 874 09-S. $247.81 each, plus shipping & handling.
K-series cast piston and 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" Oversize Ring Sets Only. Fits K301, M12 and K532 engines with 3.405" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K301, M12 and K532 engines with 3.405" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 10-S. $36.00 each, plus shipping & handling.
K-series cast piston and 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" Oversize Cast Piston with High Quality Rings. Fits K301, M12 and K532 engines with 3.415" cylinder bore. Same quality as OEM Kohler. Not available from Kohler. $45.00 each, plus shipping & handling. Ring set not available separately. L

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 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. OEM Kohler part # 47 108 05-S. Discontinued from Kohler. L

STD Size Pistons and Ring Sets. Fits K321, M14 and K582 engines with 3.500" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 11-S. $55.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 47 874 11-S. Discontinued from Kohler. L
Mahle piston and rings. OEM Kohler part # 47 874 21-S. Discontinued from Kohler. L

.003" Oversize Cast Piston and Ring Set. Fits K321, M14 and K582 engines with 3.503" cylinder bore. OEM Kohler part # 47 874 12-S. $191.75 each, plus shipping & handling.
.010" Oversize Ring Sets Only. Fits K321, M14 and K582 engines with 3.510" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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. OEM Kohler part # 47 108 06-S. Discontinued from Kohler. L

.010" Oversize Pistons and Ring Sets. Fits K321, M14 and K582 engines with 3.510" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 13-S. $52.00 each, plus shipping & handling.
K-series cast piston and 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" Oversize Ring Sets Only. Fits K321, M14 and K582 engines with 3.520" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same 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" Oversize Pistons and Ring Sets. Fits K321, M14 and K582 engines with 3.520" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 14-S. $49.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 47 874 14-S. Discontinued from Kohler. L
Mahle piston and rings. OEM Kohler part # 47 874 24-S. Discontinued from Kohler. L

.030" Oversize Ring Sets Only. Fits K321, M14 and K582 engines with 3.530" cylinder bore.

Fits K-series cast piston. High quality aftermarket. Same quality as OEM Kohler part # 48 108 08-S. $14.50 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. OEM Kohler part # 47 108 08-S. Discontinued from Kohler. L

.030" Oversize Pistons and Ring Sets. Fits K321, M14 and K582 engines with 3.530" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 47 874 15-S. $49.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 47 874 15-S. $247.81 each, plus shipping & handling.
Mahle piston and rings. OEM Kohler part # 47 874 25-S. Discontinued from Kohler. L

.040" Oversize Cast Piston with High Quality Rings. Fits K321, M14 and K582 engines with 3.415" cylinder bore. Same quality as OEM Kohler. Not available from Kohler. $60.00 each, plus shipping & handling. Ring set not available separately. L

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 quality as OEM Kohler part # 45 108 06-S. $26.00 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 and Ring Sets. Fits K341, M16 and K361 engines with 3.750" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 45 874 01-S. $85.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 45 874 01-S. $290.59 each, plus shipping & handling.
Magnum Mahle forged piston and rings. OEM Kohler part # 45 874 11-S. Discontinued from Kohler. L

.003" Oversize Cast Piston and Ring Sets. Fits K341, M16 and K361 engines with 3.753" cylinder bore.

K-series cast piston and rings. OEM Kohler part # 45 874 02-S. $309.81 each, plus shipping & handling.
Magnum Mahle forged piston and rings. OEM Kohler part # 45 874 12-S. Discontinued from Kohler. L

.010" 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. $98.65 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" Oversize Pistons and Ring Sets. Fits K341, M16 and K361 engines with 3.760" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 45 874 03-S. $85.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 45 874 03-S. $290.59 each, plus shipping & handling.
Magnum Mahle forged piston and rings. OEM Kohler part # 45 874 13-S. $317.30 each, plus shipping & handling.

.020" 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" Oversize Pistons and Ring Sets. Fits K341, M16 and K361 engines with 3.770" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 45 874 04-S. $85.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 45 874 04-S. $322.20 each, plus shipping & handling.
Magnum Mahle forged piston and rings. OEM Kohler part # 45 874 14-S. Discontinued from Kohler. L

.030" Oversize Ring Sets Only. Fits K341, M16 and K361 engines with 3.780" cylinder bore.

Fits K-series cast piston. OEM Kohler part # 45 108 09-S. Discontinued from Kohler and not available in aftermarket. L
Fits Magnum Mahle forged piston. OEM Kohler part # 45 108 13-S. $106.80 per set, plus shipping & handling.

.030" Oversize Pistons and Ring Sets. Fits K341, M16 and K361 engines with 3.780" cylinder bore.

High quality aftermarket. K-series cast piston and rings. Same quality as OEM Kohler part # 45 874 05-S. $85.00 each, plus shipping & handling.
K-series cast piston and rings. OEM Kohler part # 45 874 05-S. Discontinued from Kohler. L
Magnum Mahle forged piston and rings. OEM Kohler part # 45 874 15-S. Discontinued from Kohler. L

.040" Oversize Cast Piston with High Quality Rings. Fits K341, M16 and K361 engines with 3.790" cylinder bore. Same quality as OEM Kohler. Not available from Kohler. $85.00 each, plus shipping & handling. Ring set not available separately. L [Return To Previous Paragraph, Section or Website]

Piston Wrist Pin Retainers for 5/8" diameter wrist pins. Fits Kohler engine models K141, K160/K161, K181, M8, KT17, KT17 Series II, MV16, M18 and MV18. FYI - Snap ring retainers last longer than the OEM Cir-Clips because there's more "wear area" around them due to the flat area.

5/8" Internal Snap Ring. $1.50 each, plus shipping & handling.
5/8" Wire Cir-Clip. OEM Kohler part # 230004-S. $4.00 each, plus shipping & handling.

Piston Wrist Pin Retainers for 3/4" diameter wrist pins. Fits Kohler engine models KT19, KT19 Series II, M20 and MV20. FYI - Snap ring retainers last longer than the OEM Cir-Clips because there's more "wear area" around them due to the flat area.

3/4" Internal Snap Ring. $1.50 each, plus shipping & handling.
3/4" Wire Cir-Clip. OEM Kohler part # 52 141 01-S. $4.35 each, plus shipping & handling.

Ring Sets Only and Cast Pistons with Rings for Kohler flathead twin cylinder engine models KT17, KT17 Series II, MV16, M18 and MV18. The KT17, KT17 Series II, MV16, M18 and MV18 pistons all have the same dimensions, same wrist pin hole size (.6247"-.6249") and same compression height (1.125"), and accept the same rings. The only difference is the KT17 and KT17 Series II pistons are cast aluminum, and the MV16, M18 and MV18 pistons are forged, and made by Mahle. The KT-series rings will also fit the Mahle pistons, the Mahle pistons are not available for these engines. Priced per cylinder. To maintain engine balance and reduce vibration, two sets of matching oversize piston and rings are required. IMPORTANT: Check ring end gaps for proper clearance before installing to prevent rings from galling the cylinder wall when hot. 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. $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 Cast Pistons with Rings. (3.125" diameter cylinder bore.)

High Quality aftermarket. Replaces Kohler part # 52 875 01-S. $60.00 each, plus shipping & handling.
OEM Kohler part # 52 874 01-S. $256.90 each, plus shipping & handling.

.010" Oversize Ring Sets Only. (3.135" diameter cylinder bore.)

High quality aftermarket. $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" Oversize Cast Pistons with Rings. (3.135" diameter cylinder bore.)

High Quality aftermarket. Replaces Kohler part # 52 875 03-S. $60.00 each, plus shipping & handling.
OEM Kohler part # 52 874 03-S. $257.15 each, plus shipping & handling.

.020" Oversize Ring Set. (3.145" diameter cylinder bore.)

High Quality aftermarket. Replaces Kohler part # 52 108 11-S. $40.00 per set, plus shipping & handling.
OEM Kohler part # 52 108 11-S. $99.40 per set (for one cylinder), plus shipping & handling.

.020" Oversize Cast Piston with Rings. (3.145" diameter cylinder bore.)

High Quality aftermarket. $75.00 each, plus shipping & handling.
OEM Kohler part # 52 874 04-S. $293.00 each, plus shipping & handling.

.030" Oversize Ring Set. (3.155" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 12-S. $40.00 per set, plus shipping & handling.
.030" Oversize Cast Piston with Rings. (3.155" diameter cylinder bore.)

High Quality aftermarket. $75.00 each, plus shipping & handling.
OEM Kohler part # 52 874 05-S. $293.30 each, plus shipping & handling.

Mahle Piston, Pin, Clips with Rings for models KT17, KT17 Series II, MV16, M18, MV18. Wrist pin diameter: .6247"-.6249". Compression height: 1.125". Priced per cylinder. Rings not available separately. To maintain engine balance and reduce vibration, two sets of matching oversize piston and rings are required. IMPORTANT: Check ring gap 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. (3.125" diameter cylinder bore.)

High quality aftermarket. $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 Mahle Pistons with Rings. (3.125" diameter cylinder bore.)

High Quality aftermarket. Replaces Kohler part # 52 875 01-S. $60.00 each, plus shipping & handling.
OEM Kohler part # 52 874 01-S. $256.90 each, plus shipping & handling.

.010" Oversize Ring Sets Only. (3.135" diameter cylinder bore.)

High quality aftermarket. $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" Oversize Mahle Pistons with Rings. (3.135" diameter cylinder bore.)

High Quality aftermarket. Replaces Kohler part # 52 875 03-S. $60.00 each, plus shipping & handling.
OEM Kohler part # 52 874 03-S. $257.15 each, plus shipping & handling.

.020" Oversize Ring Set. (3.145" diameter cylinder bore.)

High Quality aftermarket. Replaces Kohler part # 52 108 11-S. $40.00 per set, plus shipping & handling.
OEM Kohler part # 52 108 11-S. $99.40 per set (for one cylinder), plus shipping & handling.

.020" Oversize Mahle Piston with Rings. (3.145" diameter cylinder bore.)

High Quality aftermarket. $75.00 each, plus shipping & handling.
OEM Kohler part # 52 874 04-S. $293.00 each, plus shipping & handling.

.030" Oversize Ring Set. (3.155" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 108 12-S. $40.00 per set, plus shipping & handling.
.030" Oversize Mahle Piston with Rings. (3.155" diameter cylinder bore.)

High Quality aftermarket. $75.00 each, plus shipping & handling.
OEM Kohler part # 52 874 05-S. $293.30 each, plus shipping & handling

Cast Pistons, Pins, Clips with Rings for models KT19 Series II, M20, MV20. Wrist pin diameter: .7499"-.7501". Compression height: 1.1875". Priced per cylinder. To maintain engine balance and reduce vibration, two sets of matching oversize piston and rings are required. The KT-series cast piston thrust face to cylinder bore oil clearance is .007"-.010". Piston with the 5/8" wrist pin for KT19 first design no longer available.

STD Size Ring Sets Only. (3.125" diameter cylinder bore.)

High quality aftermarket. $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 Cast Piston with Rings. Kohler part # 52 874 06-S. Discontinued from Kohler. L

.010" Oversize Ring Sets Only. (3.135" diameter cylinder bore.)

High quality aftermarket. $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" Oversize Cast Piston with Rings. (3.135" cylinder bore.) OEM Kohler part # 52 874 08-S. $260.95 each, plus shipping & handling.

.020" Oversize Ring Set. (3.145" diameter cylinder bore.)

High quality aftermarket. $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" Oversize Cast Piston with Rings. (3.145" diameter cylinder bore.) OEM Kohler part # 52 874 09-S. $306.70 each, plus shipping & handling.

.030" Oversize Ring Sets Only. (3.155" diameter cylinder bore.) High quality aftermarket. $40.00 per set (for one cylinder), plus shipping & handling.
.030" Oversize Cast Piston with Rings. Kohler part # 52 874 10-S. Discontinued from Kohler. L

Mahle Pistons, Pins, Clips with Rings for models KT19, KT19 Series II, M20, MV20. Wrist pin diameter: .7499"-.7501". Compression height: 1.1875". Priced per cylinder. Rings not available separately. To maintain engine balance and reduce vibration, two sets of matching oversize piston and rings are required. The Mahle forged piston thrust face to cylinder bore clearance is .0045"-.0062".

STD Size Ring Sets Only. (3.125" diameter cylinder bore.)

High quality aftermarket. $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 Mahle Piston with Rings. (3.125" diameter cylinder bore.)

High quality aftermarket. Replaces Kohler part # 52 874 16-S. $75.00 each (for one cylinder), plus shipping & handling.
OEM Kohler part # 52 874 16-S. $173.83 each, plus shipping & handling.

.010" Oversize Ring Sets Only. (3.135" diameter cylinder bore.)

High quality aftermarket. $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" Oversize Mahle Piston with Rings. (3.135" diameter cylinder bore.)

High quality aftermarket. Replaces Kohler part # 52 874 18-S. $75.00 each, plus shipping & handling.
OEM Kohler part # 52 874 18-S. $168.53 each, plus shipping & handling.

.020" Oversize Ring Set. (3.145" diameter cylinder bore.)

High quality aftermarket. $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" Oversize Mahle Piston with Rings. (3.145" diameter cylinder bore.)

High quality aftermarket. Replaces Kohler part # 52 874 19-S. $75.00 each, plus shipping & handling.
OEM Kohler part # 52 874 19-S. $163.90 each, plus shipping & handling.

.030" Oversize Ring Sets Only. (3.155" diameter cylinder bore.) High quality aftermarket. $40.00 per set (for one cylinder), plus shipping & handling.
.030" Oversize Mahle Piston with Rings. (3.155" diameter cylinder bore.) High quality aftermarket. Replaces Kohler part # 52 874 20-S. $75.00 each, plus shipping & handling. Discontinued from Kohler. L

Complete engine rebuild gasket sets w/oil seals for 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. $30.50 each, plus shipping & handling.
OEM Kohler part # 41 755 06-S. $61.70 each, plus shipping & handling.
Complete engine rebuild gasket sets w/oil seals for 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. $32.50 each, plus shipping & handling.
OEM Kohler part # 47 755 08-S. $100.70 each, plus shipping & handling.

Complete engine rebuild gasket sets w/oil seals for 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. $36.50 each, plus shipping & handling.
OEM Kohler part # 45 755 04-S. $82.90 each, plus shipping & handling.
Complete engine rebuild gasket set w/oil seals for Kohler model K361 cast iron block single cylinder OHV engine. High quality aftermarket. Discontinued from Kohler. Replaces Kohler part # 45 755 06-S.

$60.00 each, plus shipping & handling.

Complete engine rebuild gasket sets w/oil seals and valve stem seals for Kohler engine models KT17, KT17 Series II, KT19, KT19 Series II, MV16, M18, MV18, M20 and MV20.

High quality aftermarket. Does not include crankcase breather filter. $50.00 each, plus shipping & handling.
OEM Kohler part #'s 25 755 37-S, 52 755 93-S. $152.00 each, plus shipping & handling.
Complete engine rebuild gasket set w/oil seals for Kohler engine models K482, K532 and K582. Discontinued from Kohler. Replaces Kohler part # 48 755 33-S. NOTE: The gaskets and oil seals for the Kohler K482, K532 and K582 engines will not fit the K660/K662 engines.

High quality aftermarket. $40.00 each, plus shipping & handling.

"Popping" the Piston Out of the Cylinder -

"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.

IMPORTANT!

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 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 high RPM or at wide open throttle, eventually the connecting rod will break, or the bolts in an aftermarket 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/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/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 high RPM or at wide open throttle 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:

Place the crankshaft in the block along with the bearing plate.
With the rings off the piston, slide the piston, connecting rod with the bearing into the cylinder.
Rotate the crankshaft so the piston is at the TDC position.
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.
Remove the piston, and use a wide flat sanding belt or large diameter disc sander to grind off the mark and grind an angled edge on top of the piston about 3/8" back. Create about a 30º angle or smooth the grinding so it'll blend in with the top of the piston. The grinding should resemble a "crescent moon" shape on the piston.
Finally, use fine sandpaper to smooth and polish the ground 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 and K301/M12, K321/M14, K341/M16 flatheads and K361 Kohler OEM pistons, rods and crankshafts:

The K241/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 flatheads 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?

Piston explaining the compression height The compression height is the measured distance from the top of the piston to the center of the wrist pin. The stock K241/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.

Calculating the Correct Piston Compression Height - (To determine which piston and connecting rod combination will work best for a pulling engine.) Java Script will need to be enabled in your web browser for this to work.

Enter Deck Height: (From centerline of main radial ball bearings to top of block. The deck height on OEM Kohler 10-16hp blocks is 8.625".)
Enter Crankshaft Stroke: (OEM Kohler K241/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 rod bearing hole. OEM Kohler K241/M10 rods measures 5.558"; and the OEM Kohler K301/M12, K321/M14, K341/M16 and K361 rods measures 5.3". If a rod is bored .020" offset for piston pop-out [and for installation of bearing inserts], this increases the rod's length by .020".)
Enter Piston Compression Height: (Distance from centerline of wrist pin to top of piston. OEM Kohler K241/M10 is 1.62"; K301/M12, K321/M14, K341/M16 and K361 piston compression height is 1.7".)

Answer: = Piston Compression Height. (Distance from top of piston to top of engine block with piston positioned at true TDC; 0 (zero) means piston comes flush w/deck [neutral]; 0.xx means amount of piston is down in the cylinder [negative]; and -0.xx means amount of piston is protruding out of the cylinder [positive].) When the piston comes flush with the top of the engine block, this is called neutral piston height. When the piston is lower than the top of the block, this is called negative piston height, resulting in lower compression. And when the top of the piston pops out of the cylinder, this is called positive piston height, resulting in higher compression. [Return To Previous Paragraph, Section or Website]| [Top of Page]

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

On virtually any engine, crankshaft end-play/clearance 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 end-play/clearance can have an effect on the crankshaft main radial ball bearings and engine performance.

Having proper crankshaft end-play/clearance 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 end-play/clearance, 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 end-play/clearance, the piston and connecting rod will wobble side to side in the cylinder (much like the clapper in a bell). at high RPM or at wide open throttle, 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 end-play/clearance will effect the valve timing, which in turn will effect engine performance.

In a Kohler engine, insufficient crankshaft end-play/clearance will cause the main radial ball bearings to overheat and "tighten up" and produce a "whine" or "howling" sound at high RPM or at wide open throttle. The overheated bearings could also cause the engine to slow down for no apparent reason at high RPM or at wide open throttle 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 end-play/clearance and found it had insufficient clearance. After adding a shim gasket to the bearing plate so the crankshaft will have the correct end-play/clearance, 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.

In an engine that has radial ball bearings as main radial ball bearings, the steel balls in the main radial ball bearings turn the same speed as the crankshaft. If there's insufficient crankshaft end-play/clearance, and the faster the crankshaft spins, the balls in the main radial ball bearings will spin just as fast, and regardless of having high quality motor oil in the crankcase, the balls get hot, sometimes very hot. And the so-called high performance aftermarket 11- or 12-ball main radial ball bearings operate even hotter and create more friction because the smaller balls must spin faster. When this happens, they swell a few thousands of an inch. If they swell too much, crankshaft end-play/clearance is taken up and crankshaft binding occurs, which effects engine performance. This is why it's so important when rebuilding or building an engine to set the proper crankshaft end-play/clearance to specifications. I found that the OEM Kohler 8-ball main radial ball bearings works better in either a factory-stock or in a high performance or high RPM engine because these bearings have bigger balls, which spin slower, reducing their rolling resistance. 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 gaskets on the bearing plate of a Kohler engine are also shims to set the crankshaft end-play/clearance. Although a dial indicator can be used, it's much easier and quicker to use a feeler gauge to accurately measure crankshaft end-play/clearance between either main bearing and the shoulder on the crankshaft where it butts against the bearing. If the crankshaft fits a little snug in the bearings, and doesn't move side to side freely, use a heavy brass hammer to drive the crank one way or the other to check the clearance after installing the bearing plate with gaskets and after the bolts have been torqued to specs. If the clearance needs correcting, remove the bearing plate and add or remove thick or thin gaskets as required. Sometimes when a Kohler engine is reassembled, it will take several gaskets to achieve the proper crankshaft end-play/clearance. Also, with the bearing on the PTO end fully seated and the crankshaft is more or less butted against the bearing, the [OEM cast] cam timing will be in perfect alignment.

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 end-play/clearance 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 end-play/clearance anywhere between .012"-.020". I 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. I 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 front 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 end-play/clearance. 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.

How to Check the End-Play/Clearance on a Crankshaft with One or Two Tight-Fitting Main Bearings - (Added 10/7/18)

When new aftermarket or OEM main bearings fit tight or don't want to slide back and forth with little effort on the crankshaft, with the crankshaft installed in the engine and the bearing plate fastened to the block with one thick gasket and two thin gaskets, use a 2 lb. brass hammer to bump one end of the crank to check for the end-play/clearance between the crankshaft and main bearing with a feeler gauge. This is the only way it can be done. And when the end-play/clearance is set correctly with the required bearing plate gaskets, I gently bump one end of the crankshaft to more or less "center it" between the bearings.

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 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 end-play/clearances. 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 silicone sealant instead (except for the head gasket(s) on the engines).

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 [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.

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If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

NOTE: All parts listed here are NEW, unless otherwise stated. I 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.

IMPORTANT! 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 wheel bearing grease or chassis lube 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. OEM Kohler part # B-220111-S. (Has numbers 220489 embossed on rod.) $57.00 each, plus shipping & handling. (New Old Stock; when available.)

.010" undersize for .928" diameter crank journal. OEM Kohler part # B-220111-10-S. $69.00 each, plus shipping & handling.

New connecting rods for Kohler engine models K141 and K160/K161. 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 wheel bearing grease or chassis lube 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. 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 for Kohler K-series and Magnum engine models K181/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 wheel bearing grease or chassis lube 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. 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. OEM Kohler part # 41 067 09-S. $91.20 each, plus shipping & handling.

New connecting rods for Kohler K-series and Magnum engine models K241/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 wheel bearing grease or chassis lube 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 Machine Shop Service - Bore YOUR burnt or scored rod and install replaceable undersize bearing inserts for better engine protection. No need to purchase a new rod. $50.00 for labor and bearing inserts, plus return shipping & handling.
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. 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. Discontinued from Kohler. Replaces 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. Irrelevant Kohler part number. 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. $48.00 each, plus shipping & handling.

New connecting rods for Kohler K-series and Magnum engine models K301/M12 and K321/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 wheel bearing grease or chassis lube 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 Machine Shop Service - Bore YOUR burnt or scored rod and install replaceable STD size, .010", .020", .030" (hard to find now) or resizable .060" undersize bearing inserts for better engine protection. No need to purchase a new rod. $50.00 for labor and bearing inserts, plus return shipping & handling.
STD size for 1.500" diameter crank journal.

High quality aftermarket. For "old style" K-series cast piston with wide wrist pin hole. Discontinued from Kohler. Replaces 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" rod. This particular forged rod has a thicker beam section, which makes it just as strong as a 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.

.010" undersize for 1.490" diameter crank journal. (Has hole drilled through beam section.) 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. Discontinued from Kohler. Replaces 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" rod. This particular forged rod has a thicker beam section, which makes it just as strong as a 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 25-S and John Deere part # AM106832. $173.85 each, plus shipping & handling.

.020" undersize for 1.480" diameter crank journal. Irrelevant Kohler or John Deere part numbers.

High quality aftermarket. For "old style" K-series cast piston with wide wrist pin hole. $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.

New connecting rods for Kohler K-series and Magnum engine models K341/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 wheel bearing grease or chassis lube 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 Machine Shop Service - Bore YOUR burnt or scored rod and install replaceable undersize bearing inserts for better engine protection. No need to purchase a new undersize rod. $50.00 for labor and bearing inserts, plus return shipping & handling.
STD size for 1.500" diameter crank journal.

High quality aftermarket K-series rod. Discontinued from Kohler. Replaces 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 strong as a 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.) Crank journal must be reground .010" undersize to match these rods.

High quality aftermarket K-series rod. Discontinued from Kohler. Replaces 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 strong as a 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. Irrelevant Kohler part number. Irrelevant Kohler or John Deere part numbers. $58.00 each, plus shipping & handling.

ALCOA connecting rods for Kohler engine model K361. Also fits the K301/M12, K321/M14 and K341/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 wheel bearing grease or chassis lube 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 Machine Shop Service - Bore YOUR burnt or scored rod and install replaceable STD size, .010", .020", .030" (hard to find now) or resizable .060" undersize bearing inserts for better engine protection. $50.00 for labor and bearing inserts, plus return shipping & handling.
STD size for 1.500" diameter crank journal. OEM Kohler part # 45 067 15-S. $125.00 each, plus shipping & handling. (New Old Stock; when available.)
.010" undersize for 1.490" diameter crank journal. (Has hole drilled through beam section.) New. Crank journal must be reground .010" undersize to match this rod. OEM Kohler part # 45 067 17-S. $258.55 each, plus shipping & handling.

New connecting rods with a wrist pin hole diameter of .625". Fits Kohler KT-series and Magnum engine models MV16, KT17, KT17 Series II, M18, MV18. 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. 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. Crank journals must be reground .010" undersize to match this rod. High quality aftermarket. $75.00 each, plus shipping & handling.

New connecting rods with a wrist pin hole diameter of .750". Fits Kohler KT-series and Magnum engine models KT19 Series II, M20 and MV20. The rods listed below will not fit the KT19 first design engine. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

A-1 Miller's Machine Shop Service - Bore YOUR burnt or scored rod(s) and install replaceable STD size, .010", .020", .030" (hard to find now) or resizable .060" undersize bearing inserts for better engine protection. No need to purchase a new rod. $50.00 for labor and bearing inserts, plus return shipping & handling.
STD size rod. Fits 1.4993"-1.4998" diameter crank journal. High quality aftermarket. Discontinued from Kohler. Replaces Kohler part # 52 067 71-S. $75.00 each, plus shipping & handling.
.010" undersize rod. Fits 1.4893"-1.4898" diameter crank journal. Crank journal must be reground .010" undersize to match this rod. High quality aftermarket. Discontinued from Kohler. Replaces Kohler part # 52 067 72-S. $75.00 each, plus shipping & handling.
.020" undersize rod. Fits 1.4793"-1.4798" diameter crank journal. Crank journals must be reground .020" undersize to match this rod. High quality aftermarket. $75.00 each, plus shipping & handling.

New OEM connecting rods for Kohler engine models K482, K532, K582 and K660/K662 are no longer available. However, with the K482, K532 and K582 crankshaft rod journals reground to .010", .020" or .030" undersize, a connecting rod that has a burnt or scored bearing surface can be bored out to make room for matching .010", .020" or .030" undersize bearing inserts. The alternative to using bearing inserts in a connecting rod - if the bearing surface of a STD size or .010" undersize rod is in good condition and not badly scored or burnt, the rod journal(s) can be reground and "cleaned up" until perfectly round again, then the connecting rod can be resized (in a connecting rod honing machine) to fit or match the odd-size undersize journal with the factory recommended .0025" oil clearance. However, 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 could eventually knock and possibly break.

New high quality aftermarket STD size K532 and K582 connecting rod. Replaces Kohler part #'s 48 067 12-S and 48 067 16-S. $120.00 each, plus shipping & handling.
New high quality aftermarket .010" undersize K532 and K582 connecting rod. Replaces Kohler part #'s 48 067 13-S and 48 067 17-S. $120.00 each, plus shipping & handling.

Crankshaft Main Bearings (Flanged Sleeve Bushings) for Kohler engine models MV16, KT17, KT17 Series II, KT19, KT19 Series II, M18 MV18, M20 and MV20. NOTE: On these engines, one main journal can be reground undersize if it's worn beyond specifications (mostly likely the PTO end), and if the other is within specifications (most likely the flywheel end), it can remain STD size.

STD size. (1.7407") OEM Kohler part # 52 030 10-S. $77.45 each, plus shipping & handling.
.010" undersize. (1.7307") Main journal must be reground .010" undersize to match this bearing. OEM Kohler part # 52 030 11-S. $154.40 each, plus shipping & handling.
.020" undersize. (1.7207") Main journal must be reground .020" undersize to match this bearing. OEM Kohler part # 52 030 12-S. $154.40 each, plus shipping & handling.

Crankshaft Main Bearings (Sleeve Bushings) for Kohler twin cylinder engine models K482, K532 and K582.

STD size. OEM Kohler part # 48 030 06-S. $71.30 each, plus shipping & handling.
.010" undersize. Main journal must be reground .010" undersize to match this bearing. OEM Kohler part # 48 030 07-S. $161.65 each, plus shipping & handling.
.020" undersize. Main journal must be reground .020" undersize to match this bearing. OEM Kohler part # 48 030 05-S. $123.15 each, plus shipping & handling.

Flywheel End Camshaft Bushing (Bearing) for Kohler twin cylinder engine models K482, K532 and K582. NOTE: Bearing for the PTO end (part # 277039-S) is no longer available from Kohler and not available in aftermarket. L

OEM Kohler part # 48 158 03-S. $24.35 each, plus shipping & handling.

Install Bearing Inserts in Connecting Rods for Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16, K361 M20 and MV20. 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 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.

Clevite 77, Federal Mogul or Sealed Power Bearing Inserts. Available in STD size, .010", .020", .030" and .060" (limited quantity) undersizes. $20.00 each, plus shipping & handling.
Bore and notch your rod only (customer supply and install own bearing inserts): $25.00 labor, plus return shipping & handling.
Bore and notch your rod and install our bearing inserts: $45.00 ($20.00 for bearing inserts + $25.00 labor to bore rod), plus return shipping & handling.
Purchase one of our rods, bore and notch rod and install our bearing inserts: Price of rod $? + $20.00 for bearing inserts + $25.00 labor to bore rod = $? total, plus return shipping & handling.

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 want 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/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".

Narrow wrist pin width on 12hp or 14hp (old style) connecting rod for use with 16hp K-series cast piston or "new style" (Magnum) Mahle forged pistons. $20.00 labor, plus return 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 strong as a 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.

IMPORTANT! 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.

IMPORTANT! 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.

IMPORTANT! 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 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, has a heavily burnt surface (the burnt material 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, be sure to align the match marks, and it'll be best to resurface the sides of the big end on a wide flat sanding belt or large diameter disc sander slightly (with the cap torqued to the rod, of course) to ensure proper fit and side clearance on the crank journal.

By the way - 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.

IMPORTANT! 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 clean motor oil, gear oil or lubricating 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 connecting rods?

The reason many high performance engine builders prefer to use a longer, custom-made, billet [heavy duty] connecting rod is because there's less pressure from the piston skirt placed against the cylinder wall during high RPM. at high RPM or at wide open throttle, a long rod moves or "swings" side to side with less force, while a stock length rod moves 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 power. 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 offset bearing inserts are installed in a stock rod, or a longer rod/custom piston combination is used.

Because billet connecting rods are wider than OEM ones, each lower side of the cylinder wall must be ground away with a small disc grinder so the rod will clear it. The minimum clearance between the rod and cylinder wall is .050".

The billet connecting rod bolts should be torqued to 18 to 20 ft. lb. Overtorquing them could result in distortion of the big end of the rod.

IMPORTANT! 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.

IMPORTANT! 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 vibrations 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 vibrations 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:

Worn connecting rod and/or crankshaft rod journal. 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.
Loose fitting piston in the cylinder. To check for a worn beyond specifications or loose piston, with the cylinder head removed and the piston positioned at 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.
Too much crankshaft end-play/clearance. 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 end-play/clearance, you'll see it and hear it.
Worn balance gear bearings. 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.
Loose PTO pulley or electric clutch on the crankshaft. 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.
A worn Cub Cadet clutch disc will also make a knocking or rattling sound.
A loose flywheel will make a loud "clunking" sound when cranking the engine to start it. Once it starts, a loose flywheel may not make any noise.
A loud tapping sound is mainly caused by a valve with excessive stem-to-lifter clearance. 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 replaced.
A 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?

If the parts isn't warped (where metal is separated between the bolt holes), no sealant is needed on the gaskets. But if they are warped, it'll be best to apply clear RTV silicone adhesive sealant. To remove warpage and restore flatness, resurface it on a wide flat sanding belt or large diameter disc sander, or a large, flat file. 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 and 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.

Is Your "Fairly New" Aluminum Block Engine Leaking and Burning Oil?

If it's a vertical shaft engine, check for oil leakage around the sump cover gasket. Due to normal engine heat, sometimes the engine block will warp just under the cylinder on a single cylinder engine or the #2 cylinder on a twin cylinder engine. Part of the cylinder that makes contact with the sump cover will pull away from sump, creating an opening for the sump cover gasket to leak oil. This will create an air gap which allow outside air to be sucked inside the crankcase upon every upward movement of the piston(s). Then as the piston(s) travels downward, oil inside the crankcase blocks the opening. This constant buildup of excess air being drawn inside the crankcase will compress inside the crankcase and force the crankcase oil past the piston ring end gaps and cause the engine to smoke and burn oil.

To fix this...

Remove the engine (this is much easier to do on a platform work table) and place it upside-down on a work bench.
Remove the oil sump cover.
Thoroughly clean the gasket material and all parts.
Install a new oil seal in the sump cover. (The old one will probably leak from the sump being removed.)
Apply a thin bead of clear RTV silicone adhesive sealant on the engine block. 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 and 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.
Install a new sump cover gasket on the engine block.
Lubricate the crankshaft main journal and camshaft stub journal with motor oil to prevent damage due to a "dry startup."
Apply the silicone sealant on the sump cover also.
Reinstall the sump cover and torque the bolts to specs.

The engine shouldn't leak or burn oil now. But if it continues to use oil, 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 counterbore 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 counterbore.

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 counterbore.

Before installing the new oil seal, thoroughly clean the oil, dirt and debris from the counterbore, and as an option, apply medium strength liquid threadlocker (Blue Loctite or Permatex) on the edge of the seal and in the counterbore 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 counterbore. 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: Apply clean motor oil, gear oil or lubricating grease in the lip of the seal before installing to keep the seal lubricated and cool until crankcase oil can reach it. With no prior lubrication, the dry rubber will get hot from friction and burn away, causing an oil leak.

What Type of Motor Oil Should Be Used in Stock and Pulling Engines?

First of all, full synthetic/organic motor oil will allow an engine to run cooler and last longer. But the rule of thumb for different types of motor oils are: Full synthetic motor oil is mainly for high performance/racing engines that operate at high RPMs for a long time. Synthetic blend motor oil, which is a blend of about 50% organic and 50% petroleum, is for engines that occasionally operate at high RPMs, but also operate at normal speeds. And conventional/petroleum motor oil is safe to use just for engines that operate at normal speeds at all times.

Any engine with splash lubrication or without an oil filter (with an oil pump) 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 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. And the use of high quality detergent oil helps, too. Anyway, the best thing to do is place a strong magnet in the bottom of the oil pan/sump to attract the metal particles. This will help the engine last a lot longer. I think this is something that Kohler, Briggs & Stratton, Tecumseh and other small engine manufacturers should have done to their engines with splash lubrication years ago. Of course, most of these older engines last 20-30 years before they need rebuilding. But with a magnet in the oil pan or sump, there's no telling how long they would last.

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.

Motor Oil Recommendation:

SAE 30 works great for 40° F (5° C) and warmer temperatures. If used below 40° F, could cause slow cranking and hard starting.
10W30 or 10W40 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.
Full synthetic 5W30 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 for 40° F (5° C) and below is recommended for winter use, and works best in cold weather conditions.
20W50 is good for 32° F (5° C) and warmer temperatures. If used below 32° F, could cause slow cranking and hard 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 high RPM or at wide open throttle, 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 warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities and 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 - 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 metal shavings for longer engine life. 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. But make sure the oil dipper on the connecting rod doesn't make contact with the magnet!

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!)

I remember another time, a customer brought his lawn tractor with a B&S 18hp opposed twin cylinder engine to A-1 Miller's for a tune-up and repairs. I pulled the dipstick to check the crankcase oil level and condition of the oil. It was thick and black. So I asked him if he wanted the oil changed, too. He said, "What, you mean you're supposed to change the oil in these things?" And I said, "yeah, they're just like car engines. They need the oil changed regularly with fresh oil." Anyway, when I had the tractor on my repair table, I removed the oil drain plug, and nothing came out. I ran a long screwdriver in the drain hole, and it had thick, sludgy oil on it. So I removed the engine from the tractor and removed oil sump from the engine, and had to use a putty knife to literally scrape the "sludgy tar" from the oil sump! I've never seen oil this thick before, and I don't know how the engine kept internally lubricated when it ran! I tell ya, some people know absolutely NOTHING about engines! Return To Previous Paragraph, Web Site or Section È

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.

IMPORTANT! Break-In (Wear-In) Oils and Procedure for Ordinary 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. Do not allow the engine to idle at a slow speed (below 1,200 RPM) for a long period of time to break it in! It needs to run at full governed speed (3,200 or 3,600 RPMs) so the oil dipper on the connecting rod can splash the crankcase oil up and thoroughly lubricate/coat critical moving parts. And it's good to set the idle on the high side regardless of the type of oiling system (splash or oil pump) so the flywheel fins will blow more cool air over the engine. 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 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.

Break-In (Wear-In) Oils and Procedure for Fresh-Built 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. Do not allow the engine to idle at a slow speed (below 1,200 RPM) for a long period of time to break it in! It needs to run at full governed speed (3,200 or 3,600 RPMs) so the oil dipper on the connecting rod can splash the crankcase oil up and thoroughly lubricate/coat critical moving parts. And it's good to set the idle on the high side regardless of the type of oiling system (splash or oil pump) so the flywheel fins will blow more cool air over the engine. 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.

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 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. Some pullers tell me that the engines I built for them run better every time they pull them. I remember a few years ago when I performed a valve job on my truck engine. It ran good and produced plenty of power, but I noticed after about 1,000 or so miles, it produced a little more power. I realized that this is because the valve faces wore into the seats, forming a perfect seal. So again, a fresh-built pulling engine will not produce full power the first few times it's ran. Go here for more information: Valvoline.com > FAQs > Motor Oil Car FAQs > Racing Oil. Return To Previous Paragraph, Web Site or Section È

What makes crankcase oil to have a black appearance is caused by blow-by of the combustion process due to either worn piston rings, carburetor flooding or the engine running rich on fuel (gas). And if a carburetor floods or if the ignition timing is too retarded, the excess or unburned gas will seep past the piston ring end gaps and into the oil, contaminating and diluting it. When oil becomes diluted, excessive internal wear will result. The gas will also break down the additives in the oil, causing sludge. This is why it's so important to have a "fine tuned engine" and change the oil regularly. Fresh oil is cheaper than an engine or engine rebuild.

Oil Refill Quantities for Kohler Engines -

K90/K91	K141, K160/K161, K181/M8	K241A/M10, K301A/M12, K321A/M14, K341A/M16	K241/M10, K301/M12, K321/M14, K341/M16, K361	KT17, KT17 Series II, KT19, KT19 Series II, KT21, M18, M20	MV16, MV18, MV20
3/4 Quart	1-1/4 Quarts (Full mark 3/8" above oil pan gasket.)	1 Quart (narrow base flat bottom pan) 1-1/2 Quarts (narrow base deep sump pan) (Full mark 1/2" above oil pan gasket.)	2 Quarts (wide base oil pan) (Full mark 1/2" above oil pan gasket.)	1-1/2 Quarts w/filter	1-3/4 Quarts w/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. I wouldn't think it could be repaired either. So to replace the camshaft in any typical small engine on a garden tractor or lawn tractor...

First drain the oil from the engine.
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.
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.
Rotate the crankshaft so the piston is positioned exactly at TDC (Top Dead Center) 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.
Now position the engine upside-down and remove the bolts that secure the oil sump to the crankcase.
Remove the oil sump, and then the camshaft can be removed from the engine.
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.
Reassembly is opposite of disassembly.
Install a new sump cover gasket and the sump cover on the crankcase, and torque the bolts to specs.
With the piston at TDC on the compression stroke, adjust the valves to specs and install a new valve cover gasket.
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 warpage (which is unavoidable in most cases), gaskets don't always seal the irregularities and 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.
Install SAE 30 weight motor in the crankcase once the engine is reinstalled on the equipment.

IMPORTANT! 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 high RPM or at wide open throttle. 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 of the Oil Dipstick -

For Kohler engine models K141, K161, K181 and M8, the engine crankcase is at full capacity of oil with the oil level at 3/8" above the oil pan gasket. And for Kohler engine models K241/M10, K301/M12, K321/M14, K361/M16 and K361, the engine crankcase is at full capacity of oil with the oil level at 1/2" 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]

Advertisement (added 5/12/15)

If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

Expansion Cup Plug or Metal Cover Plate for blocking off oil dipstick tube hole on starter side of engine block on various Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361 when the cam gear cover type of oil dipstick tube is used.

Expansion Cup Plug. Alternative to using metal cover plate below. 1-1/16" diameter. OEM Kohler part # 25 139 47-S. $2.10 each, plus shipping & handling.
Metal Cover Plate. Alternative to using cup plug above. Made of 1/8" thick aluminum or steel. Gasket and screws not included; install with clear RTV silicone adhesive sealant or gasket below. Discontinued from Kohler. Replaces Kohler part # 237262. Fabricated A-1 Miller part. $5.00 each, plus shipping & handling.
Gasket for Oil Fill Tube Adaptor to Block. Included in complete engine rebuild gasket sets. OEM Kohler part # 237064-S. $6.90 each, plus shipping & handling.

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

First of all, prepare a cool, dry place of storage with low humidity to lessen the chance of condensation corrosion and rust.
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.
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.)
Remove the spark plug, squirt about a teaspoon-full of clean automatic transmission fluid into the combustion chamber.
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.
Run the piston at 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.
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.
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.)
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. I 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. I 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. I remember I had to grind the wrench narrow so it would fit the hex nut on the variator between the block and variator. I 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.

Advertisement. Machine Shop Services. (Prices below Ê are with the engine out of the tractor and on my work table.) [Top of Page]

If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

Engine Block -

Clean and degrease block. $7.00 labor, plus return shipping & handling.
Deglaze cylinder wall (create cross-hatch) and clean block. $20.00 labor per cylinder, plus return shipping & handling.
Hone cylinder bore to next oversize to fit OEM-type piston (OEM engine block). $75.00 labor per cylinder, plus return shipping & handling.
Bore-out and hone cylinder bore in new Kohler-replicated aftermarket block to fit aftermarket piston. $120.00 labor, plus return shipping & handling.
Clearance bottom cylinder wall for stroker crankshaft. $75.00 labor, plus return shipping & handling.
Bore cam pin holes to 11/16" (.6875") for installation of needle bearings (OEM or Kohler-replicated aftermarket block). $50.00 labor, plus return shipping & handling.
Remove expansion/welch plug and cut threads for auxiliary crankcase breather (OEM and Kohler-replicated aftermarket block. $20.00 labor, plus return shipping & handling.
Drill 7/8" center hole and two outer 1/4" bolt holes in 10-16hp Kohler blocks for installation of mechanical fuel pump. $50.00 labor, plus return shipping & handling.

Removing a Broken-Off Tap - A threading tap that has broken off in an engine block or metal casting can be very difficult to remove. About all I can tell you is to either take your block to a reputable machine shop to have the tap removed, or go here and try to do it yourself: https://www.google.com/?gws_rd=ssl#q=removing+broken+tap+from+hole. Actually, it's best to use a TAPER hand tap to cut new threads and clean out existing threads. If used correctly, a TAPER tap is less likely to break off. Click or tap here to learn how to cut new threads, the professional way.

Exhaust Port Repair/Modification Services. (K141, K161, K181/M8, K241/M10, K301/M12, K321/M14 or K341/M16 Kohler engines.)

Drill and tap two 5/16-18 UNC holes in exhaust mounting flange to install custom bolt-on exhaust system or header pipe flange. NOTE: Crankshaft and bearing plate will need to be removed from engine block so I can fasten block directly to table or in a V-shaped fixture to the table of my milling machine. An innovative concept by Brian Miller, because nobody else advertise this type of service for a Kohler engine block.

$40.00 labor, plus return shipping & handling.

Remove or drill out broken exhaust bolt(s) and recut 5/16-18 UNC (coarse thread) threads for installation of new bolts or studs. NOTE: If broken bolt(s) needs to be drilled out, crankshaft and bearing plate will need to be removed from engine block so I can fasten block directly to table or in a V-shaped fixture to the table of my milling machine. An innovative concept by Brian Miller, because nobody else advertise this type of service for a Kohler engine block.

$10.00 - $40.00 labor (depending on difficulty of work involved), plus return shipping & handling.

Resurface exhaust mounting flange to ensure 100% sealing of header flange and to prevent flange from loosening from block (due to rusted rough surface). NOTE: Crankshaft and bearing plate will need to be removed from engine block. Then with block fastened directly to table or in a V-shaped fixture fastened to the table of my milling machine, I make several passes with a grinding stone to resurface end of exhaust port. An innovative concept by Brian Miller, because nobody else advertise this type of service for a Kohler engine block.

$20.00 labor, plus return shipping & handling.

Convert 10-16hp Kohler wide base block to narrow base, for use in a Cub Cadet, Ford, John Deere, Wheel Horse, etc., garden tractor requiring a narrow base engine block. See pictures below Ê. An innovative concept by Brian Miller, because nobody else advertise this type of service for a Kohler engine block.

Cut off flanges even with sides of block. $40.00 labor, plus return shipping & handling.
Cut off flanges even with sides of block and cut new threads in oil pan mounting holes. $60.00 labor, plus return shipping & handling.
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 in oil pan mounting holes. $100.00 labor, plus return shipping & handling.

Kohler Wide Base Block Converted to a Narrow Base Block

Valve Train Related - (Prices below are with your engine on my work table.)

Perform Professional Valve Job Only on opposed (flathead) twin cylinder Kohler KT-series and Magnum engine models KT17, KT17 Series II, KT19, KT19 Series II, 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 smooth without stalling, and it will have maximum power at top governed speed. 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 sanding belt to remove 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 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 shop. To save on shipping cost, only the cylinders (removed from crankcase) and valves can be shipped in a USPS Large Flat Rate Box. Use two boxes - place one box inside the another to double the strength, and use rigid packing material to prevent the cooling fins from breaking off by making contact with each cylinder. But the short block must be shipped in a sturdy wooden crate. 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 drop off and/or pick up your carburetor, clutch assembly, cylinders, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long."

Perform Valve Job on 2 Cylinders Only. (Customer resets valve clearances.) $70.00 labor, plus return shipping & handling.
Perform Valve Job on Short Block (sheet metal, intake manifold and governor linkage removed). $200.00 labor, plus return shipping with Fastenal or FedEx Ground.
And being some valve guides wear beyond specifications, there will be an extra parts and labor charge for installing and reaming new guides, if needed.

Grind used valve to OEM angle. $3.00 each.

Grind [45°] intake valve at 30° angle. $5.00 each. (Seat must be recut or reground to 31° angle to match valve face.)

Grind seat to OEM angle or 31° angle. $3.00 each.

Perform valve job to OEM specs (grind two valve faces and seats), install valves in OEM [Kohler] block and set clearances. $25.00 labor, plus return shipping & handling.

Perform a performance valve job on two stock valves and seats in OEM [Kohler] block for improved airflow. $40.00 labor, plus return shipping & handling. Price includes grinding the exhaust valve and seat at 45°/46° angles, intake valve and seat at 30°/31° angles respectively and undercutting both valve heads.

Install oversize valves (OEM [Kohler] block). $150.00 labor, plus return shipping & handling. Price does not include any parts.

Install oversize valves (Kohler-replicated aftermarket block with small uncut valve pockets). $150.00 labor, plus return shipping & handling. Price does not include any parts.

Port/polish intake and exhaust runners (OEM and Kohler-replicated aftermarket block with large ports). $75.00 labor, plus return shipping & handling.

Port/polish intake and exhaust runners (Kohler-replicated aftermarket block with small ports). $200.00 labor, plus return shipping & handling.

Install 1-3/8" exhaust valve in 10, 12 and older 14hp OEM Kohler block. $50.00 labor, plus return shipping & handling.

Install oversize valves, and port/polish intake and exhaust runners (OEM Kohler block). $175.00 labor, plus return shipping & handling.

Install oversize valves, and port/polish intake and exhaust runners (Kohler-replicated aftermarket block). $300.00 labor, plus return shipping & handling.

Install thin-wall bronze sleeves in worn OEM valve guides in Kohler and other makes of engines. $12.00 each. Bronze valve guide sleeves are an alternative to replacing the entire guide in Kohler engines. Bronze also last longer than Kohler's cast iron guides because bronze retains more oil for better lubrication of the valve stem.

Install OEM-type [centered] cast iron valve guide or offset valve guide in OEM Kohler block and ream for clearance of valve stem. $15.00 each labor only, plus return shipping & handling. Price does not include guide.

Install bronze offset valve guide in OEM Kohler block and ream for clearance of valve stem. $15.00 each labor only, plus return shipping & handling. Price does not include guide. Oversize valve MUST be used with an offset guide.

Resurface air-cooled small engine cylinder head on large disc sander or wide, flat belt sander to remove warpage and restore flatness, and deburr sharp edge around combustion chamber. $10.00 labor, plus return shipping & handling.

Mill cylinder head approximately .050". Remove prominent/raised gasket mating surface from head to increase compression ratio for the 10-16hp flathead, K-series or Magnum single cylinder engines only. $25.00 labor each, plus return shipping & handling. NOTE: To lessen the chance of a blown or leaking head gasket, clean out the head bolt hole threads with a tap, and seal the head gasket with Copper RTV Silicone Sealant (VersaChem - Mega Copper Silicone, Permatex® Ultra Copper® Maximum Temperature RTV Silicone Gasket Maker or Copper SPRAY-A-GASKET Hi Temp Adhesive Sealant) on each side of the head gasket or cylinder head and engine block to prevent a blown or leaking head gasket. Because engine heat has very little effect on silicone rubber. It's made of fine-ground up heat-transferring compressible copper mixed with silicone. Walmart and most auto parts stores sell copper RTV silicone sealant. It doesn't matter which brand to use, they work the same.

Professionally weld up burned-out area in small engine cylinder head, resurface on a wide sanding belt to remove warpage and restore flatness, and redrill bolt hole, if needed. NOTE - As long as there's no cracks in the head, it can be successfully welded up, resurfaced, and the bolt hole redrilled. IMPORTANT - Causes of a burn-out are: Throttle shaft in the carburetor is severely worn, allowing extra air in the combustion chamber, which will lean out the air/fuel mixture at high RPMs; the adjustable high speed air/fuel mixture screw is set too lean; or the engine is ran above 3,200 RPM with a [Walbro] carburetor having a fixed/non-adjustable high speed main jet. To prevent the burn-out from happening again, either of these things should be fixed correctly before the cylinder head is put back into service. $75.00 for welding and labor, plus return shipping & handling.

A-1 Miller's Machine Shop Service - Drill out broken off [1/4"] bolt in cylinder head and retap threads for fastening of sheet metal and/or bracket. $10.00 each labor, plus return shipping & handling.

A-1 Miller's Machine Shop Service - Install a Heli-Coil thread repair insert in stripped-out spark plug hole if not larger than 5/8" in diameter. 304 stainless steel w/200,000 psi tensile strength. Includes resurfacing of air-cooled small engine cylinder head on a wide belt sander to remove warpage and restore flatness. No need to purchase another cylinder head that's in good condition. IMPORTANT: Torque spark plug to 180-240 in. lb. or 15-20 ft. lb. $15.00 each for parts and labor, plus return shipping & handling.

A-1 Miller's Machine Shop Service - Weld up stripped-out spark plug hole if larger than 5/8" diameter, and drill and tap for installation of new spark plug threads. Includes resurfacing of air-cooled small engine cylinder head on a wide belt sander to remove warpage and restore flatness. No need to purchase another cylinder head that's in good condition. IMPORTANT: Torque spark plug to 180-240 in. lb. or 15-20 ft. lb. $60.00 each for welding and labor, plus return shipping & handling.

Mill out exhaust valve cavity in LP and 2nd generation cylinder head to clear the larger 1-3/8" exhaust valve. $25.00 labor, plus return shipping & handling.

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. I 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. An innovative concept by Brian Miller, because nobody else advertise this service .
- 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. I 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.

Dynamic Precision Spin-Balancing Service -

Balance (cast or steel) flywheel for Kohler 10-16hp cast iron block engine. $75.00 each labor, plus return shipping & handling.
Balance cast iron (Kohler) crankshaft and matching connecting rod and piston assembly. $260.00 per rotating assembly, plus return shipping & handling. [Return To Previous Paragraph, Section or Website]

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A-1 Miller's Lawn & Garden, Recreational Vehicle/Early Snowmobile Engine Rebuilding and Custom Engine Build-up Services
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If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

Information About My Engine Rebuilding Service -
Small engine technology has changed a lot since the old Kohler K-series and Magnum engines were made. I can rebuild your lawn and garden engine (or competition pulling engine) with new technological parts so it'll produce more power and last longer than the factory anticipated. I also build quality engines from scratch and rebuild customer's engines from factory stock, to 4,000± RPM governed, to wide open throttle Hot Stock and Stock-Altered pulling engines. I can also build a quality, competitive engine for you, or rebuild your engine however you want. Just tell A-1 Miller's know how you're going to use your tractor or equipment and I'll build your engine to suit your needs. And despite if it's required in your club's rules or not, ALWAYS install a safety shield made of adequate thickness and material for each side of the engine fastened to the tractor frame securely in case of connecting rod failure (Murphy's Law), so an innocent bystander or spectator won't be injured or killed from high-speed projected metal shrapnel.
I don't have any rebuilt Kohler short blocks or engines in stock. And if I did, chances are, they probably wouldn't be designed for your garden tractor or equipment. Because Kohler engines are made specifically to fit a certain model of garden tractor or equipment. They are not a "universal fit" or "one fits all". Therefore, it'll be best to have your engines rebuilt instead. Then all the brackets, accessories and electrical wiring will reconnect to your garden tractor or equipment with no modifications.
Also, I set the air/fuel adjusters on all carburetors just so the engine will start and run, but because of the altitude level, barometric pressure and air temperature where the engine will be used, the customer will need to make the final adjustments so the engine will run smooth. No carburetor with an adjustable high speed main fuel adjuster comes preset, not even new ones.
Furthermore, just to let you know, although I use the best parts, use caution on choosing the right motor oil to use in your engine. Because the government (tree huggers/Sierra club) is requiring oil companies to lessen the amount of zinc in their motor oils to reduce pollution. Zinc provides a protective coating on internal engine parts and prevents metal to metal contact for proper break-in and it helps the parts last longer. Many auto manufacturers and professional engine rebuilders are upset because of this too, because they have to guarantee their engines for a certain period of time, and many of them take pride in building their engines.
Regarding an Engine Build Estimate -
I am very meticulous in how I rebuild and build engines. If you wish to have A-1 Miller's build, rebuild or build-up your engine, I will need a detailed list of exactly what you want done to your engine or a copy of your club's pulling rules regarding the engine requirements before I can give you an estimate on the cost. And if you (the customer), change your mind of how you want the engine built or rebuilt in the middle of a build, I will need to know ahead of time and I will need the changes in writing so I can make the necessary changes to the engine. Otherwise, this will effect how well the engine performs on the track, and it would make me, as a professional engine builder, look bad. It's not a good thing to be afraid that something bad may happen to an engine. Having confidence in an engine makes ya feel good, but having confidence in your engine builder makes ya feel better.
I do not build illegal pulling engines that do not conform to your club's rules! But there are certain other engine builders that offer new pulling engines for sale. BUT, being different pulling associations/clubs have different engine rules and requirements, there is no "one pulling engine that conforms to each and every clubs' rules." Therefore, you may receive an engine that do not conform to your club's rules, and it may be built "above the rules". Meaning it's not legal within your club's rules and is illegal to run in the class you plan to pull it in (cheater engine). Or, the engine in question may be built "below the rules" so it's less competitive as an engine that is built legally to the max according to the rules. But I'll build your engine or an engine for you so it'll produce the maximum horsepower and torque in accordance with your club's rules, not less than what the rules allow. I also rebuild ordinary/stock lawn and garden equipment engines too, such as cast iron and cast aluminum block single- and twin-cylinder flathead, OHV and v-twin Briggs and Stratton, Kohler, Tecumseh and 2-cycle LawnBoy. I've never encountered an engine that I couldn't repair, rebuild or build-up for more power!
Whenever I rebuild or build-up an engine, and if you wish to do so, I do whatever it takes so it'll produce the factory-rated horsepower or the maximum horsepower and torque, and last a long time. I go beyond what the repair manual says to do. I can get all the parts needed, too. I can build your engine so it'll be legal for the class you plan to pull in. And with my engine rebuilds and build-ups, you may not always win, but you'll look good trying! By the way - the surface of the exhaust area of a fresh-built engine may burn off the oil residue for a short time once it gets hot, but it'll stop after a while. It's nothing to worry about. This happens with most rebuilt engines, especially an engine with fresh paint.
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 and when the engine breaks-in. 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-out/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 needs to be set at .035". The valve to lifter clearances may need to be reset at .010" for the intake and .014" for the exhaust.
FYI - Used OEM parts in good condition for older Kohler engines are hard to find now, especially the small parts. If the parts don't wear, they tend to get thrown away and then "engine scrappers" sell the parts that do wear on places like eBay. They don't think about people like me, who make a living by "piecing together" or building engines from scratch for a customer. I can purchase new parts from Kohler if they're still available, but that would be cost-prohibitive. I try to keep my engine builds at reasonable prices. - Brian Miller
Things that we perform to a 10-16hp Kohler engine to greatly improve engine performance:

Precision dynamically spin-balance the rotating assembly (crankshaft/rod and piston, and flywheel) for a smoother running engine and improved overall engine performance.
Mill the head about .050" to raise the compression ratio.
Bore the connecting rod offset .020" and install bearing inserts to pop the piston out of the cylinder approximately .020" to raise the compression ratio even more.
Enlarge the intake and exhaust port runners to increase airflow in and out of the combustion chamber. (Only for competition pulling engines.)
Bore-out the venturi and professionally rework the carburetor (only for competition pulling engines) to increase airflow into the combustion chamber to raise the compression pressure.
Install a heat isolator carburetor mounting gasket with a phenolic resin center.
Install stiffer springs (only for competition pulling engines) for more responsive valve action.
Install a heavy steel flywheel (only for competition pulling engines) to increase the engine torque (lugging power).
Index the spark plug (only for competition pulling engines) so the open gap faces the center of the piston for more efficiency burning of the fuel, resulting better fuel combustion.
Install electronic ignition for a stronger and more stable spark than points and condenser.

All of my customer's competition pulling engine builds are strictly confidential! This means the people you pull against will not know what goes into your engine.

Below Ê are details and prices to rebuild your engine -

Briggs and Stratton 16, 18 and 20hp opposed (flathead) twin cylinder aluminum block engine (horizontal or vertical shaft) professional rebuild to OEM factory specifications @ 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. NOTE: If your engine doesn't smoke out the exhaust and burn oil, then chances are, all it needs is a professional valve job performed. We can do this instead of rebuilding your engine. The price is $300.00 for parts and labor to perform the valve job, plus return shipping.

Professionally Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Parts and labor includes: Completely disassemble engine, thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or bore cylinders and install new oversize piston/rings assemblies; regrind valves and seats, if needed, regrind crank journals and resize connecting rods with .0025" oil clearance, or install new matching undersize rods, resurface cylinder heads to remove warpage and restore flatness, rebuild carburetor with a new overhaul kit, install tune-up kit, install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable).

Briggs and Stratton Vanguard V-twin aluminum block engine (horizontal or vertical shaft) professional rebuild to OEM factory specifications @ 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Parts and labor includes: Completely disassemble engine, thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or bore cylinders and install new oversize piston/rings assemblies; regrind valves and seats, if needed, regrind crank journals and resize connecting rods with .0025" oil clearance, or install new matching undersize rods, resurface cylinder heads to remove warpage and restore flatness, rebuild carburetor with a new overhaul kit, install tune-up kit, install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable).

Kohler engine models K90/K91 cast iron block flathead engine professional rebuild to OEM factory specifications @ 4,000± governed RPM (for general lawn and garden use). All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $450±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on extent of wear and availability of rebuild parts. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Basic Parts and Labor Include: Completely disassemble engine, thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or if needed, bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; if needed, regrind crank journal and resize connecting rod with .0025" oil clearance, or install new matching undersize rod, resurface cylinder head to remove warpage and restore flatness, rebuild carburetor with a new overhaul kit, install tune-up kit, install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable). Extra charge for A-1 Miller's custom flywheel-trigger electronic ignition system. Price depends on type of electronic ignition system installed.

Kohler engine models K141, K160/K161, K181 and M8 cast iron block flathead engine professional rebuild to OEM factory specifications @ 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: K141, K160/K161, K181 or M8 w/2-7/8" or w/2-15/16" cylinder bore: $600±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Basic Parts and Labor Include: Completely disassemble engine; thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or if needed, bore cylinder and install new oversize piston/rings assembly; if needed, install rotator on the exhaust valve so any carbon deposits will be wiped away from valve face and seat to prevent valve burning; if needed, regrind crank journal and resize connecting rod with .0025" oil clearance, or install new matching undersize rod; resurface cylinder head to remove warpage and restore flatness; rebuild carburetor with a new overhaul kit; install tune-up kit; install rubber seal in governor shaft bushing to prevent oil seepage; install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable). Extra charge for A-1 Miller's custom flywheel-trigger electronic ignition system.

Kohler K-series and Magnum engine models K241, K301, K321, K341, M10, M12, M14 and M16 professional rebuild to OEM factory specifications up to 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Basic Parts and Labor Include: Completely disassemble engine; thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or if needed, bore cylinder and install new oversize piston/rings assembly; if needed, install rotator on the exhaust valve so any carbon deposits will be wiped away from valve face and seat to prevent valve burning; if needed, regrind crank journal and resize connecting rod with .0025" oil clearance, or install new matching undersize rod, or bore rod and install bearing inserts; resurface cylinder head to remove warpage and restore flatness; rebuild carburetor with a new overhaul kit; install tune-up kit; install rubber seal in governor shaft bushing to prevent oil seepage; install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable). Extra charge for A-1 Miller's custom flywheel-trigger electronic ignition system.

Kohler K-series or Magnum engine models K241/M10, K301/M12, K321/M14 and K341/M16 Stock-Appearing professional build to the max up to 4,000± RPM for heavy lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Basic Parts and Labor Include: Completely disassemble engine, thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or if needed, bore cylinder and install new oversize piston/rings assembly; if needed, install rotator on the exhaust valve so any carbon deposits will be wiped away from valve face and seat to prevent valve burning; if needed, regrind crank journal and resize connecting rod with .0025" oil clearance, or install new matching undersize rod, or bore rod and install bearing inserts; resurface cylinder head to remove warpage and restore flatness, rebuild carburetor with a new overhaul kit, install new tune-up kit; install rubber seal in governor shaft bushing to prevent oil seepage; install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable). Extra charge for A-1 Miller's custom flywheel-trigger electronic ignition system.

Kohler K-series engine model K361 OHV professional rebuild to OEM factory specifications up to 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $800 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Basic Parts and Labor Include: Completely disassemble engine, thoroughly clean and inspect the block and all parts for wear and/or damage; install new STD size piston/rings assembly or if needed, bore cylinder and install new oversize piston/rings assembly; if needed, install rotator on the exhaust valve so any carbon deposits will be wiped away from valve face and seat to prevent valve burning; if needed, regrind crank journal and resize connecting rod with .0025" oil clearance, or install new matching undersize rod, or bore rod and install bearing inserts; resurface cylinder head to remove warpage and restore flatness, rebuild carburetor with a new overhaul kit, install new tune-up kit; install rubber seal in governor shaft bushing to prevent oil seepage; install new gaskets and oil seals. If engine has a broken connecting rod or rods, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable). Extra charge for A-1 Miller's custom flywheel-trigger electronic ignition system.

Perform Professional Valve Job Only on Kohler Engine Model K361 Cylinder Head. 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 smooth without stalling, and it will have maximum power at top governed speed. Click or tap here for cylinder head bolt torque specs.

Repair loose valve seat with a new bronze valve seat. FYI - Bronze grips or adheres to aluminum much better than steel. Plus, it's harder than cast iron. $75.00 each for parts and labor, plus return shipping & handing.
Repair worn inside of valve guide with a bronze sleeve insert. $12.00 each for parts and labor, plus return shipping & handing.
Replace loose guide valve with an oversize O.D. guide. $40.00 each for parts and labor, plus return shipping & handing.
Resurface head gasket mating surface to remove warpage and restore flatness. $20.00 labor, plus return shipping & handing.
Perform valve job to OEM specs (regrind both valve faces and seats), install valves, springs, retainers and keepers/locks/collets. $35.00 labor, plus return shipping & handling.

Individual Gaskets and Complete Gasket Kit to Reinstall K361 Cylinder Head on Engine -

Head Gasket. High quality aftermarket. Discontinued from Kohler. Replaces Kohler part # 45 052 02-S. $24.00 each, plus shipping & handling.
Rocker Arm Housing Gasket. Discontinued from Kohler. NOS OEM Kohler part # 45 041 14-S. $14.40 each, plus shipping & handling.
Rocker Arm Cover Gasket. OEM Kohler part # 45 041 09-S. $6.45 each, plus shipping & handling.
Two Pushrod Tube Rubber O-Rings s. High quality aftermarket. Replaces Kohler part # 45 153 01-S. $1.00/two, plus shipping & handling.
Intake Tube Mounting Gasket. High quality aftermarket. Replaces Kohler part # 271030-S. $1.00 each, plus shipping & handling.
All parts above total: $46.85, plus shipping & handling.

Complete engine rebuild gasket set w/oil seals for Kohler K-series model K361 cast iron block single cylinder OHV engine. High quality aftermarket. Discontinued from Kohler. Replaces Kohler part # 45 755 06-S.

$50.00 each, plus shipping & handling.

High Quality Aftermarket K361 Valve. Can be used as intake or exhaust valve. Heat-treated, hardened steel. Dimensions: head diameter: 1.437"; overall length: 4.165"±; face angle: 45º. Has 8mm chrome-plated stem. Requires 8mm reamer to enlarge guide. OEM Kohler valve keepers/locks/collets and retainers or rotators can be used with this valve. OEM valve discontinued from Kohler. Replaces Kohler part #'s 45 016 02-S (intake) and 45 017 01-S (exhaust).

Machined by A-1 Miller's. $50.00 each, plus shipping & handling.

NOTE: Before lapping in valves, it's best to have the valve seats recut or reground so the angle will be in correct alignment with the centerline of the valve guides and so the valve face will make a full 360º contact with the seat, or the valves will leak and the engine will lose compression, be hard to start, be low on power and possibly make a popping sound through the carburetor or out the exhaust. And be sure to set the clearances correctly, too.

Valve Guides for Kohler engine model K361 cylinder head.

Intake Valve Guide. OEM Kohler part # 45 316 02-S. $14.20 each, plus shipping & handling.
Exhaust Valve Guide and Seal Kit. OEM Kohler part # 45 755 11-S. $62.23 per kit, plus shipping & handling.

Kohler KT-series and Magnum opposed (flathead) twin cylinder engine models KT17, KT17 Series II, KT19, KT19 Series II, MV16, M18, MV18, M20 and MV20. Professional rebuild to OEM factory specifications @ up to 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Complete Engine Rebuild. Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Parts and labor includes: Completely disassemble engine, thoroughly clean and inspect block and all parts; install new STD size piston rings, or bore cylinders and install new oversize piston/rings assemblies (price will be higher for the boring and with a new oversize piston and rings); regrind valves and seats, install new valve guides (if needed), resurface cylinder heads (on large disc sander or wide, flat belt sander) to remove warpage and restore flatness; rebuild carburetor, install new gaskets and oil seals and install new tune-up kit. If engine was run out of oil and have a broken connecting rod or rods, and internal damage has resulted, the price will be higher for additional parts and labor (if rebuildable). If one or both cylinders are scored and needs to be replaced with new piston and rings, the price will be slightly higher. But cylinder scoring is rare. If either cylinder wall and/or piston(s) is/are scored and needs replacing, the price will be slightly higher. For these type of engines, we don't have the cylinders bored oversize and install new oversize piston and rings because this would be too cost prohibitive being we have good used cylinders and pistons in stock. Add $150.00 for installation of A-1 Miller's custom flywheel-trigger electronic ignition system. (KT-series engines only.)

Perform Professional Valve Job Only on opposed (flathead) twin cylinder Kohler KT-series and Magnum engine models KT17, KT17 Series II, KT19, KT19 Series II, 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 smooth without stalling, and it will have maximum power at top governed speed. 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 sanding belt to remove 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 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 shop. To save on shipping cost, only the cylinders (removed from crankcase) and valves can be shipped in a USPS Large Flat Rate Box. Use two boxes - place one box inside the another to double the strength, and use rigid packing material to prevent the cooling fins from breaking off by making contact with each cylinder. But the short block must be shipped in a sturdy wooden crate. 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 drop off and/or pick up your carburetor, clutch assembly, cylinders, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Perform Valve Job on 2 Cylinders Only. (Customer resets valve clearances.) $70.00 labor, plus return shipping & handling.
Perform Valve Job on Short Block (sheet metal, intake manifold and governor linkage removed). $200.00 labor, plus return shipping with Fastenal or FedEx Ground.
And being some valve guides wear beyond specifications, there will be an extra parts and labor charge for installing and reaming new guides, if needed.

Kohler engine models K482, K532 and K582 opposed (flathead) twin cylinder (flathead) engines. Professional rebuild to OEM factory specifications @ up to 3,600 governed RPM for general lawn and garden use or mild competition pulling. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. NOTE: If your engine doesn't smoke out the exhaust and burn oil, but looses power, then chances are all it needs is a professional tune-up and valve job performed. We can do this instead of rebuilding your engine. The price is $300.00 for parts and labor to perform the valve job, plus return shipping.

Rebuild YOUR engine: $1,200±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Parts and labor includes: Completely disassemble engine, thoroughly clean and inspect block and all parts; install new STD size piston rings, or bore cylinders and install new oversize piston/rings assemblies (price will be higher for the boring and with a new oversize piston and rings); regrind valves and seats, install new valve guides (if needed), resurface cylinder heads (on large disc sander or wide, flat belt sander) to remove warpage and restore flatness; rebuild carburetor, install new gaskets and oil seals and install new tune-up kit. If engine was run out of oil and have a broken connecting rod or rods, and internal damage has resulted, the price will be higher for additional parts and labor (if rebuildable). If one or both cylinders are scored and needs to be bored oversize with new oversize piston and rings, the price will be slightly higher.

Kohler Command and Command Pro V-Twin Engine Models CH18, CH20, CH22, CH23, CH25, CH620, CH621, CH640, CH641, CH670, CH680, CH730, CH740, CH750, CH940, CH960, CH980, CH1000, CV16, CV17, CV18, CV20, CV22, CV25, CV620, CV640, CV670, CV680, CV730 and CV740. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

Generac V-Twin Engine Models 005682-0, 0E3480, 0E4328, 389cc, 5625-0, GH-220, GH-410, GN-190, GN-220, GN-320, GN-360, GN-410, GT-760, GT-990, GTH-990, GTV-760 and GTV-990. NOTE: As long as new replacement parts are available, these engines can be rebuilt. All sheet metal will need to be removed before bringing or shipping engine to A-1 Miller's. Engine must be shipped in a sturdy wooden crate. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Rebuild YOUR engine: $700 - $1,000±, includes high quality parts and labor, plus return shipping with Fastenal or FedEx Ground. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. Price depends on model of engine and extent of wear. A 50% deposit may be required on certain engine rebuilds. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine rebuild.

A-1 Miller's Kohler Competition Pulling Engine Building | [Top of Page]
Garden tractor pulling engine technology has changed a lot through the years. I can rebuild your competition pulling engine with new technological parts so it'll produce more power, be more competitive on the track and last longer than anticipated.
The below Ê are high output engines, built and designed for competition pulling only, not general lawn and garden use. No charging system included. 10hp (K241), 12hp (K301), 14hp (K321) or 16hp (K341) Kohler engines built by Brian Miller.
The "Built to the Max" Stock class engines runs at governed 4,000± RPM; has a 9-1/2" cast flywheel with majority of fins removed then dynamically and precision spin-balanced; high torque upper mount gear starter (mounting bolts are below the starter motor); performance valve job with stock size valves; A-1 Miller's reground/torque cam; medium performance valve springs; #26 or #30 Kohler carburetor (depending on engine size) bored-out, reworked and set up for gas; enlarged ports and polished (intake port made larger only if it is smaller in diameter than the carburetor throttle bore); 2nd or 3rd generation cylinder head milled .050"; connecting rod bored .020" offset for piston pop out with bearing inserts. Also included are: flywheel shroud (not chrome plated), cast iron or aluminum oil pan, bolt-on header pipe and conventional Kohler point ignition system installed with ignition timing preset. And being there is no oil filter on Kohler cast iron block engines, an oil drain plug with a very strong rare earth/neodymium magnet, or a very strong rare earth/neodymium magnet will be glued to the inside bottom of the oil pan or engine base to attract and remove ferrous metallic wear fragments from the motor oil to clean the oil so the engine will last much 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. An innovative and ingenious concept by Brian Miller because nobody else advertise this trick online for a pulling engine.
A-1 Miller's rebuilt engines will be painted with high quality gloss black, unless the customer specifies a different color or no paint at all. When you receive the engine, install it in the tractor, add motor oil to the proper level, install the fuel hose, add fuel, connect the ignition and starter wires, connect the throttle controls, and the engine will be ready to start. Carburetor adjustments will be initially preset, but due to the altitude level, barometric pressure and air temperature, final idle speed, idle air/fuel mixture and high speed air/fuel mixture adjustments may need to be made after the engine is started and warmed up. It'll have no charging system. Use a remote battery charger to recharge the battery before each pulling event.
4,000 RPM "Built to the Max" Stock-Appearing Pulling Engines below - built for competition pulling only and to your pulling association/club's sanctioning rules. In addition to all the essentials, prices below include a heavy (ring gear) steel flywheel and new high torque gear starter motor (Kohler style). Custom crank trigger ignition or $100 to build a sturdy wooden shipping crate and shipping & handling is extra charge. Or you can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.

Build to the Max 10hp Kohler Engine. Dyno'd at 15hp± @ 4,000 RPM and 19± ft. lbs. of torque @ 4,000 RPM. Horsepower/torque and price depends on how the engine is built. (Past engines test ran on A-1 Miller's personal dynamometer with accurate results.)

If customer provides engine block and most parts. $2,000±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,000±.

Build to the Max 10hp 27 CID Hybrid Stroker Engine. Dyno'd at 19hp± @ 4,000 RPM and 25± ft. lbs. of torque @ 4,000 RPM. (Past engines test ran on A-1 Miller's personal dynamometer with accurate results.)

If customer provides engine block and most parts. $2,300±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,100±.

Build to the Max 12hp Kohler Engine. Dyno'd at 22hp± @ 4,000 RPM and 29± ft. lbs. of torque @ 4,000 RPM. Horsepower/torque and price depends on how the engine is built. (Past engines test ran on A-1 Miller's personal dynamometer with accurate results.)

If customer provides engine block and most parts. $2,000±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,000±.

Build to the Max 14hp Kohler Engine. Dyno'd at 25hp± @ 4,000 RPM and 33± ft. lbs. of torque @ 4,000 RPM. Horsepower/torque and price depends on how the engine is built. (Past engines test ran on A-1 Miller's personal dynamometer with accurate results.)

If customer provides engine block and most parts. $2,000±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,000±.

Build to the Max 16hp Kohler Engine. Dyno'd at 28hp± @ 4,000 RPM and 37± ft. lbs. of torque @ 4,000 RPM. Horsepower/torque and price depends on how the engine is built. (Past engines test ran on A-1 Miller's personal dynamometer with accurate results.)

If customer provides engine block and most parts. $2,300±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,300±.

Hot Stock or Sport Stock Pulling Engines - built to your pulling association/club's sanctioning rules. The Hot Stock class engines has an OEM Kohler block; runs at wide open throttle (no governor); 9-1/2" 25 lb. steel flywheel; high torque upper mount gear starter (mounting bolts are below the starter motor); A-1 Miller's Hot Stock/Stock-Altered welded-up and reground cast camshaft; single high performance valve springs; performance valve job with stock size valves; #26 or #30 Kohler carburetor (depending on engine size) bored-out, reworked, set up for gas with bottom main fuel adjuster; enlarged ports and polished (if the intake port is smaller in diameter than the carburetor throttle bore); 2nd or 3rd generation cylinder head milled .050"; connecting rod bored .020" offset for piston pop out with bearing inserts; rotating assembly (crankshaft and connecting rod/piston assembly) precision spin-balanced to reduce engine vibration. Also included are: flywheel shroud (not chrome plated), cast iron oil pan, bolt-on header pipe and conventional Kohler point ignition system installed with ignition timing preset. Upon receiving engine, install in tractor, add fluids and engine will be ready to start after all connections are made. Carburetor adjustments will be initially preset, but due to the altitude level, barometric pressure and air temperature, final adjustments may need to be made after engine is started. Prices below Ê do not include $100 for crating and shipping & handling. You can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. Add $110.00 - $152.00 for installation of A-1 Miller's custom crank trigger or flywheel triggered electronic ignition system.

Hot Stock or Sport Stock - 12hp Kohler engine block. Dyno'd at 48hp± and 39± ft. lbs. of torque @ 6,500 RPM. (Past engines test ran on A-1 Miller's personal dynamometer.)

If customer provides engine block and most parts. $2,200±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,500±.

Hot Stock or Sport Stock - 14hp Kohler engine block. Dyno'd at 50hp± and 41± ft. lbs. of torque @ 6,500 RPM. (Past engines test ran on A-1 Miller's personal dynamometer.)

If customer provides engine block and most parts. $2,400±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $3,500±.

Hot Stock or Sport Stock - 16hp Kohler engine block. Dyno'd at 53hp± and 44± ft. lbs. of torque @ 6,500 RPM. (Past engines test ran on A-1 Miller's personal dynamometer.)

If customer provides engine block and most parts. $2,600±. NOTE: All parts must be new or in good, usable condition.
If A-1 Miller provides engine block and all parts. $4,000±. NOTE: Price will be higher if an aftermarket block is used.

Competition Pulling Engine Freshening Service Ê This service is for competition pulling engines only that have been previously built, and needs the basic parts and labor to revive the power. It is not a complete engine rebuild. A typical pulling engine will last an average of 25 pulls or 3 years of use. After that, the piston rings become worn, and the engine may lose power when under load and puff gray/blue smoke out the exhaust and/or crankcase breather vent. When this happens, it's time for a freshening job. If interested, we will need an updated copy of your association/club's engine rules so when the engine is freshened, it will be legal in its class, but still competitive. Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines. Add $110.00 - $152.00 for installation of A-1 Miller's custom crank trigger or flywheel triggered electronic ignition system. (For competition pulling only.) A 50% deposit may be required on certain engine refresh jobs. Deposit is non-refundable if labor and machine work is invested in the engine, and parts are purchased for the engine. Remaining balance of total amount is due upon completion of engine refresh. [Top of Page]
Freshen Stock "Built to the Max" 10-16hp 4,000± RPM governed Kohler pulling engine. Includes install new high quality ring set or piston and rings; clean and reseat valves or perform 3-angle high flow performance valve job; install new bearing inserts; clean, rebuild or bore-out/rework carburetor; install our reground 4,000 RPM torque performance camshaft; new gaskets and oil seals.

$200.00 more or less, depending on which parts & how much labor the engine needs, plus return shipping with Fastenal or FedEx Ground. I will need an updated copy of your association/club's engine rules so when I freshen the engine, it will be legal in its class, but still competitive.

Freshen Hot Stock 12-16hp Kohler engine. Includes install new high quality ring set or piston and rings; clean and reseat valves or perform 3-angle high flow performance valve job; new bearing inserts; clean, rebuild or bore-out/rework carburetor; if needed, install our welded up and reground Hot Stock/Stock-Altered performance camshaft; new gaskets and oil seals.

$300.00 more or less, depending on which parts & how much labor the engine needs, plus return shipping with Fastenal or FedEx Ground. I will need an updated copy of your association/club's engine rules so when I freshen the engine, it will be legal in its class, but still competitive.

NOTE: The Stock-Altered class engine is very much like the 16hp Hot Stock engine, except these engines burn methanol, the carburetor is restricted to a 1" venturi with a maximum 1" thick mounting spacer, and is allowed to use a billet cylinder head. The Stock-Altered engine may also have either an OEM Kohler or aftermarket (MSWC) engine block. Other than that, these two engines are basically the same. These engines runs at wide open throttle (no governor); has a 9-1/2" 25 lb. heavy steel flywheel; high torque upper mount gear starter (mounting bolts are below the starter motor); A-1 Miller's Hot Stock/Stock-Altered welded-up and reground cast high performance camshaft; single high performance valve springs; performance valve job with stock size valves; #26 Kohler carburetor, venturi bored to 1", reworked, set up for methanol with bottom main fuel adjuster and velocity stack; enlarged ports and polished (intake port made larger only if it is smaller in diameter than the carburetor throttle bore); billet cylinder head milled; billet connecting rod with bearing inserts; rotating assembly (crankshaft and connecting rod/piston assembly) precision spin-balanced to reduce engine vibration. Also included are: flywheel shroud (not chrome plated), cast iron oil pan, bolt-on header pipe and conventional Kohler point ignition system installed with ignition timing preset. Upon receiving engine, install in tractor, add fluids and engine will be ready to start after all connections are made. Carburetor adjustments will be initially preset, but due to the altitude level, barometric pressure and air temperature, final adjustments may need to be made after engine is started. IMPORTANT: Click or tap here for proper break-in (wear-in) oils and procedure for rebuilt engines.
NOTES: ± means more or less, depending on how the engine is built in accordance with your pulling club's engine rules and restrictions, and if customer provide some of the parts. Engines are built as customers order them according to their tractor's make and model. I will need a copy of your pulling club's sanctioning engine rules and requirements so I can build your engine so it'll produce the maximum power and still be legal within its class.
And a 50% deposit may be required on certain engine builds. Balance due upon completion of engine. And I don't offer any chrome-plated sheet metal or chrome-plated header pipes because these parts are cost-prohibited. Please contact A-1 Miller's if you're interested in any of the above È parts or services.

A-1 Miller's Computerized Stuska Water Brake Engine Dynamometer (Dyno) Service with DPM Data Logger Software to Test Horsepower and Torque! | [Top of Page]
For performance testing of 10-16hp single cylinder Kohler stock or competition pulling engines at speeds up to 12,000 RPM. 100% accurate, customers can rent dyno time, fine tune and make adjustments or changes to their engines to gain maximum horsepower and torque, and print-out the results so their tractor(s) will be truly competitive on the track. With an engine dyno, the puller can adjust their engine to get maximum horsepower and torque, and gear their tractor appropriately to have an advantage over the competition. NOTE: A fresh-built engine may not produce full power until it's broke-in. This is when the valves wear-in with the seats to completely seal in the compression. The rings will likely hold the compression, but the valves may leak slightly until they wear into the seats. This is normal for all engines and may take several hours or pulls to happen, then the valves will be able to hold full compression. Lots of pullers tell A-1 Miller's after I've built their engines that it seems to pull stronger every time they pull it.
Engine Dyno Rental Fee: $50.00 per hour run time from the moment the engine is started. No setup fee for Cub Cadet engines with a 3- or 6-pin/stud clutch driver. An adapter may need to be needed or fabricated for other makes and models of engines. Only engines with the narrow base oil pan can be tested. Engines with the wide base (tall) oil pan cannot be tested at this time. [Return to Previous Section, Paragraph or Website]

NOTES:

A general stock engine rebuild includes: completely disassemble entire engine, clean and inspect all parts, bore (if it needs it) or deglaze cylinder, install new piston/rings/pin/clips assembly, regrind crankshaft journal (if it needs it), install new undersize (.010") connecting rod or bore rod for undersize bearing inserts (.020" or .030"; if it needs it), grind valves and seats, install new gaskets with clear RTV silicone adhesive sealant to lessen oil leaks, install new ignition tune up components, resurface cylinder head to remove warpage and restore flatness, clean and rebuild carburetor, clean commutator and lubricate bushings in gear starter and whatever else the engine may need so it'll run well and last a long time. 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 and imperfections between surfaces metals, 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.
The engines I sell are turn key engines. I build all engines according to the customer's personal preferences for non-pulling purposes or to the customer's pulling club's sanctioning rules. "Build to the max" means engine will produce all the power possible and still remain stock-appearing externally. All of the above È will be performed in addition to the mild performance modifications.
± means more or less. This means if your engine needs minimal labor and/or machining, the price will be slightly less. But if it needs more than usual labor and/or machining, the price will be slightly higher. However, if it has sustained major internal damage or if it needs additional parts, extensive machine work and more labor, then the price will be even higher. And being I can't see your engine before you bring or send it to us, I can't honestly give an exact quote beforehand. But we'll treat you right and we'll try to keep the costs down as much as possible and still build you a quality engine so it'll start easy, produce full power and last a long time. The ± also depends on your personal preferences, parts needed and/or your pulling club's sanctioning rules. Also, if you wish to provide some or all of the parts yourself, the price will be substantially lower.
Before sending or bringing your engine to me, I don't need everything on it. Just the parts that can wear and need rebuilding or reconditioning, such as the gear starter, cylinder head(s), crankcase breather assembly, fuel pump and carburetor. I need the oil pan on it too, to prevent any dust and dirt from entering the crankcase after the rebuild. Please remove all sheet metal, too. I'll need the flywheel on the engine so I can set the ignition timing. Regular shop hours are 9:00 am - 5:00 pm, Monday-Friday, except Holidays. If you are traveling a great distance, it's best to call in advance (573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly) to make sure that I will be here when you plan to stop by.
All rebuilt engines returned or shipped to the customer come with a 90 day workmanship warranty from date of pickup or delivery. FREE professional technical support comes with part of the warranty.

To place an order, please call or email A-1 Miller's with your name, complete mailing address and phone number and so I can figure the total with shipping cost and USPS Tracking. All prices are based on a 2% cash discount. For payment options for parts ordered or services performed, or to make a donation to my websites, 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 for the credit/debit card processor's surcharge), Western Union Money Transfer or MoneyGram Money Transfers. (If the engine and/or part(s) is/are for a specific purpose and/or make and model of tractor, your debit/credit card may be charged for the full amount or as a deposit right after your order is placed; please do not send your credit or debit card information in email!) Or you can pay A-1 Miller's through PayPal. (My PayPal account name is my email address. And be sure to mention in PayPal a description of what the payment is for.) If sending a money order, please include a note in the envelope with your name, complete mailing address, phone number and a description of what the payment is for. My mailing address and phone number are below Ê. And I will send you the engine or parts as soon as I receive your payment or when the order is processed.

Ship the Engine in a Sturdy Wooden Crate - [Return To Previous Paragraph, Section or Website]

IMPORTANT! If you bring an engine to A-1 Miller's in person, place it in an old automotive tire to keep it from moving around during transportation. And please let A-1 Miller's know first so I can expect your arrival. But if you decide to ship your engine to me, I don't need everything on it. Just the parts that can wear and need rebuilding or reconditioning, such as the gear starter, cylinder head(s), crankcase breather assembly, fuel pump and carburetor. I need the oil pan on it too, to prevent any dust and dirt from entering the crankcase after the rebuild. Please remove all sheet metal and PTO clutch/pulley, too. I'll need the flywheel on the engine so I can set the ignition timing. Please send or bring your engine when you're ready to the address below Ê. By the way - I have a heavy duty 2-jaw gear puller that we use with a large c-clamp to remove the mechanical PTO clutch/pulley from Cub Cadet engines. But sometimes these clutch/pulleys will not remove without breaking. I do all I can to try to prevent this from happening, but when they do break, I have no choice but to install a rebuilt PTO clutch/pulley assembly. I also made a special puller tool to remove the large stamped steel PTO pulley from the crankshaft without damage.

To ship your engine to A-1 Miller's, first off, do not use the USPS, UPS or FedEx Express! We and our customers have had too many problems with these shippers in the past. Their clumsy, incompetent and uncaring "gorilla" workers have a tendency to damage heavy items, and the shipping company's insurance never pay off. The shipping company claim that the damaged item, which was in their possession, is "not their fault." They are very careless with heavy packages when they handle them. The packages are placed on conveyor-belt systems and they seem to always drop the heavy ones off of the elevated conveyors, which usually destroys whatever is inside them. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your [irreplaceable] high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's shop to personally drop off and/or pick up your engine, transaxle, tractor, etc., for modifying, rebuilding or repairs.

If shipping an engine, and if the crated engine weighs no more than 150 lbs., use only Fastenal or FedEx Ground for dependability. The average crated cast iron block Kohler engine weighs just under 150 lbs. Use this website to calculate the shipping cost for your engine: FedEx Rates and Transit Times. Contact your local Fastenal or FedEx Ground shipping center for more details and to schedule a pickup or drop off the crated engine at your local Fastenal or FedEx Ground shipping center. Fastenal and FedEx Ground are the only reasonably-priced shipping service that I know of for items up to 150 lbs. US Mail only ship up to 70 lbs. And FedEx Freight would cost almost as much as an engine is worth. If your engine is too heavy to go with FedEx Ground, partially disassemble it and send the lightweight parts in a USPS Large or Medium Flat Rate Box, and then send the main short block with FedEx Ground, the crated engine can be shipped through Fastenal. This also works better to save money on shipping costs. You can visit A-1 Miller's shop to drop off and pick up your engine to save on crating and shipping charges.

Do not use a cardboard box alone the ship a heavy engine! Crate it well and any other parts with it securely so they won't get damaged or lost in shipping. A sturdy and well-constructed wooden crate can be ordered from: Crates, Wooden Crate in Stock - ULINE. But to construct your own sturdy wooden shipping crate, use 2x2's or 2x4's lumber for the frame work, with 1/4" plywood or 1/2" chipboard as outer covering (do not use cardboard for covering because another person's package could penetrate it and cause damage the engine inside), and a couple of 2x4's or a cut-down shipping pallet on the bottom so a forklift can move it without damage. Make the crate compact as possible so it'll take up less space, save on shipping charges and so it'll be easier to move around in our shop. Fasten the engine oil pan mounting bolt holes to two sturdy 2x4's on the base of the crate securely with 3/8" diameter bolts with wide flat washers. It's also very important to install 2x4 wood bracing all around the engine cylinder (front, rear and each side) stabilize it in the crate. And for easy engine removal, PLEASE use Phillips head drywall/sheetrock screws or better yet, use hex head 1/4" lag bolts w/flat washers to fasten everything on and in the crate. Be sure to include a note in a sealed plastic bag with your name, complete and correct postal address, phone number, email address (in case I have any questions) and a detailed description of how you want the engine built and what it will be used for, and mention in the note any other parts you may need.

When the work is completed, I'll contact you with the total including return shipping & handling. For payment options for parts ordered or services performed, or to make a donation to my websites, 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 for the credit/debit card processor's surcharge), Western Union Money Transfer or MoneyGram Money Transfers. (If the engine is for a specific purpose and parts must be special ordered, full payment will be required right after your order is placed or your debit/credit card will be charged for the full amount or as a deposit.) Or you can pay A-1 Miller's through PayPal. My PayPal account name is my email address, and be sure to mention in PayPal a description of what the payment is for. If sending a money order or cashier's check, please include a note in the envelope with your name, complete mailing address, phone number and a description of what the payment is for. My mailing address and phone number are below Ê. And I will ship your rebuilt engine/parts to you as soon as I receive your payment.

To ship a transaxle, this is easier. They don't require an enclosed crate. Just place the transaxle on the center of a shipping pallet (of the appropriate size) and stretch wrap (use low-cost ratchet nylon tie-downs) to securely fasten it to the pallet. Use at least 6 layers of stretch wrap or several tie-downs. This should work really well. The shipping weight of a Cub Cadet cast iron case transaxle when strapped to a wooden pallet is approximately 215 lbs.

We prefer to use FedEx Ground (for anything up to 150 lbs.) and FedEx Freight (for anything over 150 lbs.) because they've been proven to be the lowest cost, most gentle and reliable shipping companies. Here's a great web site that calculates freight charges. Go here: http://www.shipgooder.com/ and type in your zip code, our zip code (65203-9136) and the crated weight of a typical complete 10-16hp Kohler engine (145 lb.). Shipgooder doesn't ship anything. It's website just lets you see the latest cost of various shipping companies. Contact your local FedEx Ground or Fastenal shipping centers for more details and to schedule a pickup. Or you can use a major trucking company with a good reputation for shipping heavy, fragile objects. Look in the Yellow Pages and ask around. The reason we say this is because we once returned a rebuilt engine that was crated very well to a customer using a well-known shipping company, and it was almost destroyed in shipping when he received it. You'll have better success with shippers such as FedEx Ground, FedEx Freight, Roadway, etc. Freight company employees are trained in handling heavy packages plus they use tow motors to move the freight around, not like UPS or FedEx Express when their clumsy "gorillas" or incompetent and uncaring workers unload and load the trucks. The approximate shipping weight of a crated 7 and 8hp Kohler engine is 100 lbs. And 10-16hp single cylinder cast iron Kohler engine is 145 lbs. Again, 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 drop off and/or pick up your engine, transaxle, tractor, etc. [Return To Previous Paragraph, Section or Website]

Coming Soon - Detailed Illustrated Plans on How to Construct a Professional Pull-Back and Self-Propelled Garden Tractor Pulling Sled. FYI - The professionally-built self-propelled pulling sled is the only one I've ever built (click the picture to the right to see a larger image of this sled), and I got it right the first time, with very few changes or modifications that had to be made to it. I guess I'm just one of those kind of guys that knows what he's doing. Pullers really like pulling our sled, too. They say it's the best sled they've ever pulled. (Not bragging, just stating a fact.) By the way - Track Master sled is engineered so well (by Brian Miller), that other sled builders/owners have copied my well thought-out and proven design. And I do appreciate them acknowledging my intelligence. Anyway, I have lots of work to do in my shop and I work on the sled plans in my spare time. As soon as my plans with an inventory list of parts to use are perfected, I'll post the update in my websites with the prices of the plans. Remember - Perfection takes time. If it's worth having, it's worth waiting for. Also, I plan to acquire a bigger shop and may build high quality garden tractor pulling sleds in the future to offer for sale. Please call 573-256-0313 (shop) or 573-881-7229 (cell; text or voice message), or email pullingtractor@aol.com if interested. - Brian Miller

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

To place an order, please call the number below Ê or send an email with your name, complete and correct postal address and phone number and so I can figure the total with shipping cost and USPS Tracking. For payment options for parts ordered or services performed, or to make a donation to my websites, 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 for the credit/debit card processor's surcharge), Western Union Money Transfer or MoneyGram Money Transfers. (If a part for a specific purpose is special ordered, your debit/credit card may be charged for the full amount or as a deposit right after your order is placed; please do not send your debit/credit card information in email!) Or you can pay A-1 Miller's through PayPal. (My PayPal account name is my email address. And be sure to mention in PayPal a description of what the payment is for.) If sending a money order, please include a note in the envelope with your name, complete and correct postal address, phone number and a description of what the payment is for. My mailing address and phone number are below Ê . I'll make a note of your order, and I may have to order some of the parts, which should take a few days to come in, but I will send the parts to you as soon as I have everything in stock after I receive your payment.

IMPORTANT - When sending your part(s) to A-1 Miller's for rebuilding or repair, package everything securely so the item(s) won't get damaged in shipping and please include a note in the box with your name, mailing address, phone number (in case I have any questions) and a description of what you want done. When shipping heavy parts, it's best to put a slightly smaller box inside a larger box, to double the strength and support of the package. Because the clumsy "gorillas" or incompetent and uncaring workers that work for certain delivery services mishandle the heavy packages and don't care. And when the work is completed, I'll either call or email you an invoice with the total including shipping & handling.

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.

We Accept PayPal, Visa, MasterCard, American Express & Discover Credit & Debit Cards To make a payment to A-1 Miller's through PayPal, go to PayPal's secure website ( https://www.paypal.com/ ) and click on Send and Request -> Pay for goods or services. Type in my email address, or copy and paste this: pullingtractor@aol.com, the amount and follow the directions. Be sure to mention in PayPal a description of what the payment is for. After you've finished, PayPal will send A-1 Miller's an email notifying me that you have made a payment to A-1 Miller's for the product(s) or services and amount entered. Then I go to their website and direct PayPal to deposit the money in my bank account. And I will send the parts to you as soon as I receive your payment. But I may have to order some of the parts if they're not in stock, which should take a few days. In that case, I will send you the parts as soon as they come in. PayPal protects your financial privacy and security. With PayPal, privacy is built in. It's a way for you to pay without exposing their financial information.

Or to make a payment to me (pullingtractor@aol.com) in the US through the Venmo app, please tap this link: venmo.com.

Or use Cash App to make a payment to me (pullingtractor@aol.com).

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If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises \| 1501 W. Old Plank Rd. \| Columbia, MO (Missouri) 65203-9136 USA \| Phone: 1-573-256-0313 (shop) \| 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop \| 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. 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 drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)
Crankshaft Repairs - This includes Briggs & Stratton, Kohler, Tecumseh, etc. Remove burnt aluminum and polish journal to shiny finish. I chuck the crankshaft in my big metal lathe, turn it on slow and use my crankshaft polisher with a belt sander to remove the burnt aluminum. This works great until the aluminum is gone, but sometimes the journal is scored or worn. Then it require regrinding to the next undersize. If it's not scored or worn, then it can be reused as is. But if it is worn, an undersize rod and possibly one with a bearing insert is required. If it does need regrinding, then there's no charge for cleaning it. $10.00 per journal, plus return shipping & handling. Regrind journal (crank pin) to next undersize. NOTE: Kohler crankshafts can be reground to .030" undersize and still be safe to use with matching undersized replaceable 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. I also do 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. Single cylinder engine crankshafts: $75.00 per journal, plus return shipping & handling. Two cylinder engine crankshafts: $100.00 per journal, plus return shipping & handling. "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. An innovative concept by Brian Miller, because nobody else advertise this service . 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 5/8" stud on flywheel end of crankshaft. Center drill and cut threads for a 3/8" diameter grade 8 bolt in the end of crankshaft. $25.00 labor, plus return shipping & handling. Drill hole and cut 7/16-20 UNC (fine thread) threads in the PTO end of the crankshaft for bolt and flat washer. $25.00 labor, plus return shipping & handling.
Dynamic Precision Spin-Balancing Service - Balance (cast or steel) flywheel for Kohler 10-16hp cast iron block engine. $75.00 each labor, plus return shipping & handling. Balance cast iron (Kohler) crankshaft and matching connecting rod and piston assembly. $260.00 per rotating assembly, plus return shipping & handling. [Return To Previous Paragraph, Section or Website]
Main Crankshaft Radial Ball Bearings for Kohler K-series and Magnum cast iron block engine models K141, K160, K161 and K181/M8. Heat treated. These are specifically designed to provide maximum performance through precise ball implement selection. Aftermarket bearing packed with fresh grease from the factory. Dimensions: 1.18" I.D. (30mm) x 2.44" (62mm) O.D. x .62" (16mm) width. See note below Ê. NOTE: If yours 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 needs to be replaced. FYI - All ball bearings have always been made to the metric dimensions. Where applicable, the US and import manufacturers try to make them close to the inch dimensions as possible. New High quality aftermarket. Our part # 150-960. Same quality as OEM Kohler part # 231625-S. $10.00 each, plus shipping & handling. New OEM Kohler part # 231625-S. $55.55 each, plus shipping & handling. 8 Ball Main Crankshaft Radial Bearings for Kohler K-series and Magnum cast iron block engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361. Heat treated material. These are specifically designed to provide maximum performance through precise ball implement selection. Works excellent for general lawn and garden engines or high performance engines that run at high RPM or at wide open throttle. Bigger balls rotate freer and run cooler, which create less rolling resistance and friction than a bearing with smaller balls. Aftermarket bearing packed with fresh grease from the factory. Dimensions: 1.57" (40mm) I.D. x 3.54" O.D. (90mm) x .90" (23mm) width. See note below Ê. NOTE: If yours 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 needs to be replaced. FYI - All ball bearings have always been made to the metric dimensions. Where applicable, the US and import manufacturers try to make them close to the inch dimensions as possible. Used and in excellent condition with very little to no wear. OEM Kohler part # 235376-S. $5.00 each, plus shipping & handling. (When available.) New high quality aftermarket. Our part #150973. Same quality as OEM Kohler part # 235376-S. $22.00 each, plus shipping & handling. New. OEM Kohler part # 235376-S. $116.55 each, plus shipping & handling. NOTE: With the main bearings removed from an engine, and if all the oil is cleaned from the bearings, allowed to thoroughly dry, and then the bearings are spun by hand, and if the bearings isn't worn much or at all, they might feel "rough" and make a rattling sound. This rattling sound isn't necessarily because the bearing is worn. The noise is caused by the balls running dry on the races because there's no oil to separate them. They're simply making metal to metal contact. Try applying a small amount of motor oil to the balls/races and then spin them. They should now be a lot quieter. The same thing will happen with new radial ball bearings. By the way - Most main bearings in a Kohler engine will wear extremely little, if any at all, and usually don't require replacing. Although some main bearings will wear (which is obvious), and need to be replaced. And excessively worn main bearings will make a rumbling noise and the engine will have a more than-usual-vibration.
Flywheel Retaining Nuts for 5/8" or 3/4" threaded stud on end of Kohler K-series and billet steel crankshafts. OEM type of nuts discontinued from Kohler. 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 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 Kohler part #'s X-89-11, X-119-16. $3.00 each, plus shipping & handling.
Flywheel Retaining Bolt and Washer Kit for 3/8" threaded hole in end of crankshaft. Grade 8, 3/8" diameter, fine thread (3/8-24 UNF) bolt, split lock washer and extra thick washer. Most of these parts discontinued from Kohler. IMPORTANT: Apply thin coat of motor oil in threads of crankshaft or on bolt then torque 40 ft. lb. High quality aftermarket. $5.00 each, plus shipping & handling.	Starter Pulley Retaining Bolt/Washer Kit for PTO end of crankshaft. Comes with grade 8, 3/8" or 7/16" bolt, split lock washer and extra thick washer. Certain professional pulling associations/clubs require this in case starter pulley comes loose on crankshaft and become an airborne projectile, which can cause serious injury to a bystander or spectator. Choice of 3/8" or 7/16" bolt sizes. $5.00 per kit, plus shipping & handling.
Rectangular Steel Crankshaft/Flywheel 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. Discontinued OEM Kohler part # X-366-1-S. Used and in excellent condition. $5.00 each, plus shipping & handling. (When available.) Square Steel and Aluminum Crankshaft/Flywheel Keys. Fits Kohler engine models K141, K160, K161, K181, M8, K241, K301, K321, K341, K361, KT17, KT17 Series II, KT19, KT19 Series II, MV16, M18, MV18, M20 and MV20 made in 1973 and later. Dimensions: 3/16" square x 1-3/8" length. Steel Flywheel Key. High quality aftermarket. $1.00 each, plus shipping & handling. Steel Flywheel Key. OEM Kohler part # X-286-17-S. $1.90 each, plus shipping & handling. Aluminum Flywheel Key. Made of 6061 medium-grade hardness alloy aluminum. Helps prevent possibility of cracking/breaking of factory flywheel due to sudden crankshaft lock-up in the event of connecting rod failure. Replaces Kohler part # X-286-17-S. $5.00 each, plus shipping & handling. Woodruff (Semicircular) Steel Keys for Crankshaft/Flywheel and Gear Reduction Shaft on certain Kohler engine models K241, K301, K321, K341, and all Magnum models M10, M12, M14, M16, and models CH13 and CH15. Dimensions: 3/16" wide x 1" length. High quality aftermarket. $1.00 each, plus shipping & handling. OEM Kohler part # X-46-3-S. $2.25 each, plus shipping & handling. Woodruff (Semicircular) Steel Crankshaft/Flywheel Key. Fits most OHV aluminum block Kohler engines. Dimensions: 3/16" wide x 5/8" length. High quality aftermarket. $1.00 each, plus shipping & handling. OEM Kohler part # X-42-15-S. $1.70 each, plus shipping & handling.

Example of Model K160 - K = K-series engine \| 16 = Cubic inch displacement (approximate) \| 0 = before Kohler designated 1 is for a 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 K161 - K = K-series engine \| 16 = Cubic inch displacement (approximate) \| 1 = One/single cylinder engine.	Example of Model M14PT - M = Magnum series engine \| 14 = Horsepower rating \| PT = Pump model/Retractable start

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

PARTS FITTED	SIZE OR CLEARANCE	PARTS FITTED	SIZE OR CLEARANCE
Minimum safe idle speed Maximum safe operating speed	1,200 RPM (±75 RPM) 3,200 RPM	Breaker cam to camshaft pin	.001" - .0025"
Cylinder Bore - Standard	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 - Models with Splash Lubrication	.003" - .008" .005" - .010"	Valve stem in guide - Exhaust - Intake	.002" - .0035" .002" - .005"
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 - 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

Engine Model			M8	M10	M12	M14	M16
General Information	Factory-Rated Horsepower @ Maximum Safe Operating Speed (See note 8 below)		7hp @ 3,200 RPM 8hp @ 3,600 RPM	9hp @ 3,200 RPM 10hp @ 3,600 RPM	10.6hp @ 3,200 RPM 12hp @ 3,600 RPM	12.4hp @ 3,200 RPM 14hp @ 3,600 RPM	14.2hp @ 3,200 RPM 16hp @ 3,600 RPM
	Minimum Safe Idle Speed (±75 RPM) (See note 9 below)		1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM	1,200 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 Gear	Shaft O.D.	New	-	<-.4998"-.5001"->
		Maximum Wear Limit	-	<-.4996"->
	End-Play/Clearance		-	<-.002"-.010"->
Camshaft	End-Play/Clearance (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"->
	Rod to Journal Side Clearance (min.-max.)		<-.010"-.025"->
	Small End I.D. (max.)		.6255"-.6258"	.8596"-.8599"	<-.8757"-.8760"->
Crankshaft	Main PTO 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"->
	End-Play/Clearance (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)	RCJ-8	<-RH-10->
		Gap	<-.025"->
	Module Air Gap		<-.012"-.016->
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"->

Engine Model	MV16	M18, MV18	M20, MV20	KT17, KT17 Series II	KT19, KT19 Series II	K482	K532	K582	K660/K662
Factory-Rated Horsepower @ Maximum Safe Operating Speed (See note 2 below)	14.2hp @ 3,200 RPM 16hp @ 3,600 RPM	16hp @ 3,200 RPM 18hp @ 3,600 RPM	17.8hp @ 3,200 RPM 20hp @ 3,600 RPM	17hp @ 3,600 RPM	19hp @ 3,600 RPM	18hp @ 3,600 RPM	20hp @ 3,600 RPM	23hp @ 3,600 RPM	24hp @ 3,200 RPM
Minimum Safe Idle Speed (±75 RPM) (See note 7 below)	1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM	1,200 RPM
Engine Construction	<-Aluminum Block / Cast Iron Cylinders->					<-Cast Iron Block w/Integrated Cylinders->
Cubic Inch Displacement (STD Bore)	42.18	42.18	47.00	42.18	47.00	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	5.8:1	6.4:1	7:1	?
Piston Stroke	<-2.750"->		3.062"	2.750"	3.062"	2.875"	3.000"	3.000"	3.250"
Cylinder Bore (New)	<-3.125"->					3.250"	3.375"	3.500"	3.625"
Cylinder Bore (Worn)	<-3.128"->					3.253"	3.378"	3.503"	3.6245"
Cylinder Taper	<-.0015"->								.002"
Cylinder Out of Round	<-.002"->					<-.005"->
Crankshaft End-Play/Clearance (Engines w/Sleeve Bearing)	<-.002"-.014"->					<-.004"-.010"->			.0035"-.0055"
Crankshaft End-Play/Clearance (Engines w/Ball Bearing)	<-.002"-.023"->					--
Crankshaft Main Front / Rear 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 Front / Rear Diameter (Engines w/Ball Bearing)	<-1.378"->					<-1.772"->
Crankshaft Main Sleeve Bearing Oil Clearance	<-.0013"-.0033"->					<-.0015"-.004"->			?
Crankpin New Diameter	<-1.3733"-1.3738"->		1.500"	1.3733"-1.3738"	First Design - 1.3733"-1.3738" Series II - 1.4993"-1.4998"	<-1.625"->			?
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"->				First Design - 1.376" Series II - 1.5025"		<-1.627"->		?
Connecting Rod Big End to Crank Pin Clearance	<-KT17 First Design and KT19 First Design 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"	.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"	<-.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	<-.003"-.006"->					<-.008"-.010"->			.006"-.008"
Exhaust Valve to Tappet Clearance Cold	<-.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 Clearance in Guide	<-.0005"-.0024"->					<-.0012"-.0023"->			?
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 Nominal Gap	<-N/A->			<-.017"-023" (See note 6 below)->		<-.020"->
Ignition Timing Spark Run	<-N/A->			<-23º BTDC->		<-22.5º BTDC->			?
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.

The following specialty tools are required to disassemble, reassemble and rebuild a single- or 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) Piston ring compressor Quality-made automotive harmonic balancer puller to remove the flywheel	Valve lapping tool and valve grinding compound (which can be purchased online and at virtually any auto parts store) Feeler gauge set to set the valve clearances, camshaft end-play/clearance and crankshaft end-play/clearance Two torque wrenches that reads in inch- and foot-pounds of torque Multimeter set on Ohms resistance or test light and two small jumper wires to set ignition timing
More sophisticated tools or tooling and machinery is required to perform machine work on certain engine components, such as: bore the cylinder, regrind the crankshaft journal(s), bore connecting rod for installation of replaceable bearing inserts, recut or reground the valve faces and seats, automotive ignition distributor clamp wrench (to fasten cylinder nuts on opposed twin cylinder engines), etc. In most cases, the valves can be reground. But if they're severely worn, they need to be replaced. I sell most of the parts required to perform a complete engine rebuild. Most common parts are: piston and rings, gaskets w/oil seals, valves, carburetor kit and tune up kit.