Vital Information about Engine Rebuilding, Buildups and Modifications

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FYI - Some people ask me for Cub Cadet engine parts. Well, Cub Cadet don't manufacture engine parts, Kohler (or whatever make of engine is installed in the tractor) does. Most Cub Cadet dealers can get Kohler engines and parts because they're also a Kohler dealer. I'm a Kohler engines and parts dealer too, but not a Cub Cadet dealer. This means I can't order Cub Cadet parts from a Cub Cadet distributor. As of now, I have to get my parts from a local Cub Cadet dealer and pay retail.


Kohler Engine Identification Numbers -

The engine model and serial numbers appears on a metal tag or decal that's attached or affixed to the flywheel shroud, on the carburetor side of the engine. If there's no tag or decal that originally came with the engine, or if the engine block was replaced with a replacement short block or if the blower shroud has been replaced, there's no way of knowing exactly what year the engine is. All you'll know is the year of the blower shroud itself. Tags/decals and flywheel shrouds can be swapped from one engine to another and there are no numbers or identification characteristics on the blocks themselves (except for the 10hp through 14hp engines has 9 head bolts, the 16hp has 10 head bolts and the 18hp is OHV). Therefore, to see what size the engine actually is, it's best remove the cylinder head and measure the bore and stroke to determine engine size. Because a 10hp can be bored and stroked to a 12hp, using a 12hp piston, rod and crank, and a 12hp can be bored to a 14hp, using a 14hp piston, rod and crank.

Bore, stroke and valve sizes of 4hp through 18hp single cylinder Kohler engines:

Engine K90 (3.6hp)
K91
(4hp)
K141
(6¼hp)
K160
(6.6hp)
K161
(7hp)
K181
(8hp)
K241
(10hp)
K301
(12hp)
K321
(14hp)
K341
(16hp)
K361
(18hp OHV)
Bore (std.) 2.375" 2.875" 2.875" 2.938" 2.938" 3.250" 3.375" 3.500" 3.750" 3.750"
Stroke 2.000" 2.500" 2.500" 2.500" 2.750" 2.875" 3.250" 3.250" 3.250" 3.250"
Valve Sizes 1.262" int.
1.262" exh.
1-3/8" int.
1-1/8" exh.
1-3/8" int.
1-1/8" exh.
1-3/8" int.
1-1/8" exh.
1-3/8" int.
1-1/8" exh.
1-3/8" int.
1-1/8" exh.
1-3/8" int.
1-1/8" exh.
1-3/8" int.
1-1/8" exh. (early)
1-3/8" exh. (late)
1-3/8" int.
1-3/8" exh.
1-7/16" int.
1-13/32" exh.

MODEL NO. (Deciphering model number to determine basic description of engine.)

Example: Model K321PT
K = K-series engine | 32 = Cylinder displacement (approximate cubic inch) | 1 = Single cylinder | PT = Pump model/Retractable start (Version code below Ê)

Another example: Model K301AQS
K = K-series engine | 30 = Cylinder displacement (approximate cubic inch) | 1 = Single cylinder | A = Narrow Base Block and/or Special Oil Pan | Q = Quiet Model (Quiet Line) | S = Electric Start (Version codes below Ê)

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

SERIAL NO. (Year engine was manufactured.)

[E] - 1 7 2 452
Letter code
[9 0] 7 6 4 3 0
First two digits (if seven digit number).
[1 0 0] 2 6 6 9 2
First three digits (if eight digit number).
[1 5] 0 1 8 9 7 5 9 1
First two digits (if ten digit number).
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....1985
15............(late)1985
16....................1986
17....................1987
18....................1988
19....................1989
20....................1990
21....................1991
22....................1992
23....................1993
24....................1994
25....................1995
The remaining digits of serial number are factory code (line/shift at factory when engine was assembled on that day). These numbers are for warranty purposes only.

SPECIFICATION NO. Engine Code à Model
Code   à  Model

26, 27, 31......K91 (4hp)
28..................K161 (7hp; [large bore])

Code   à  Model

29 .................K141 (6¼hp; [small bore])
30 .................K181 (8hp)

Code   à  Model

46..................K241 (10hp)
47..................K301 (12hp)

Code   à  Model

60..................K321 (14hp)
71..................K341 (16hp)

NOTE: The three numbers and the letter following the first two numbers (not shown above È) are the specific variation to the engine to meet OEM specifications. No information is available from Kohler to what these numbers represent.


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 electronic 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 Magnum model M10, M12, M14 or M16 (10-16hp) engine can be used in a Cub Cadet. The block will need to be converted to a narrow base by cutting off the flanges on each side and cut threads in the holes in the block for a narrow oil pan. 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" to 3/8" reducer/step washer. (I make these.) Everything else should fit in the tractor with no problems.

BUYER BEWARE! A word of caution before purchasing a used pulling 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 refuses to allow the head and pan to be removed, then it'll probably be best not to purchase the engine.

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.


Why Aluminum Block Engines (except V-Twins) Don't Work Well for Pulling Competition -

Most aluminum engine blocks will "bend and twist" a few thousands of an inch when hot and under pulling stress. Therefore, they'll 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 under the stress of pulling.

If the crankcase is building up too much air pressure in an OHV aluminum block engine, and blowing oil out the crankcase breather, the main cause of this the cylinder head(s) are warped and needs to be resurfaced on a large, flat sanding disc. New head gaskets needs to be installed, too. What happens is the metal in the heads between the pushrods (where there is no head bolt) become warped due to normal engine operating heat. New aluminum "bends and twists" a few thousands of an inch as the block and head(s) get hot for the first time. Crankcase oil plugs the gap as the piston travels downward on the intake stroke, and part of the compression goes into the crankcase upon the compression stroke. The engine will probably not blow oily smoke out the exhaust either. Once repaired, this shouldn't happen again.

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 very high rpm (above 4,000 rpm). This is why riding mowers, lawn tractors, lawn and garden tractors all 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, like Kohler engines can.

These are things that can be done to virtually any flathead twin cylinder engine to gain more power and torque:

  1. Check that the cylinder walls are in good condition and not severely scored or worn. If they're in good condition, deglaze them, and if the pistons are reusable, install new piston rings.
  2. If it's a Kohler engine model KT17II, KT19II, M18 or M20, leave out the cylinder-to-crankcase gaskets and apply Clear RTV Silicone Adhesive Sealant instead. Doing this should allow the pistons to come approximately .030" closer to the top of the cylinders, increasing the compression ratio slightly. By the way - I've always preferred to use Clear RTV Silicone Adhesive Sealant for two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen between the parts.
    NOTE: It's not recommended to use the series 1 engine models KT17, KT19 or KT21 because these engines don't have a pressure relief valve in the oil pump lubrication system, which could cause insufficient oiling to one of the connecting rod journals.
  3. Perform a professional valve job. If it isn't already, regrind the intake valve faces and seats at a 30°/31° angles, respectively, and regrind the exhaust valve faces and seats a 45°/46° angles, respectively.
  4. Set the valve clearances at .006" for the intake valves and .010" for the exhaust valves.
  5. Resurface the cylinder heads on a flat sanding disc to insure proper head gasket sealing.
  6. In each cylinder head, relocate tip of spark plug closer to exhaust valve. To do this, weld up the spark plug hole, bore an angled hole toward the exhaust valve, then cut threads and mill seat area able for installation of the spark plug.
  7. Use full synthetic 10W40 motor oil. Full synthetic oil don't get hot like conventional (petroleum-based) oils do. It's more slippery and remains cooler even after the engine has been in operation for several hours to better protect internal parts for longer engine life. And I don't think it matters which brand of synthetic oil to use, because they all pretty much do the same thing.

FYI- Boring the cylinders to a maximum of .030" and installing .030" oversize pistons and rings won't help to increase the power that much. It'll only add about 1/10th of a horsepower with virtually no increase in torque. What increases the torque substantially is giving the engine a longer stroke. 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 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, the engine should start quicker, idle better, accelerate with less hesitation and produce more power and torque at any rpm.

To perform a professional valve job on a twin cylinder flathead B&S or Kohler engine, the parts that will be needed are: two head gaskets, two crankcase breather gaskets, intake manifold mounting gaskets and valve stem seals (for intake valves only). New valve guides, especially for the exhaust valves, may also be needed. But that's to be determined once the valves are removed. A quality-made valve spring compressor tool is required to remove and reinstall the valves. The valve faces and valve seats angles are to be reground or recut at 45° (intake valve face for Kohler), 30° (intake valve face for B&S) and 46° (intake and exhaust seats for Kohler & exhaust seat only for B&S), 31° (intake seat for B&S), respectively. If you can't do this yourself, a local automotive machine shop can do it for you. You'll need to take the engine or tractor to the shop to have the valve seats reground or recut. Make sure they're reground or recut at the proper angle, too! And it'll be a good idea to have both cylinder heads resurfaced on a flat sanding disc to ensure proper head gasket sealing. The head bolts can be reused. They rarely go bad. Top of page


Why aluminum block engines (except v-twins) don't work well for pulling competition - Top of page

An aluminum engine block will "bend and twist" or flex a few thousands of an inch when hot and under pulling stress. Therefore, they'll 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 under the stress of pulling.

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. Because cast iron is able to "hold its shape," handle high operating temperatures, severe stress, high compression and high rpm. This is why most riding mowers, lawn tractors and lawn & 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 & 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 are angled). Therefore, Kohler are capable of producing more compression, and they can flow the air better in and out of the combustion chamber at high rpm.


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

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.


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

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.

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 flat sanding disc to insure 100% gasket sealing, and bore the cylinder to insure 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 to be Rebuilt - (Most of 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:

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.

Kohler engines can be rebuilt multiple times, as long as everything in it is rebuildable. Before the engine is removed from the tractor and disassembled, 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 sleeved back to STD size.

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.

And if the crank journal is worn, it can be reground undersize and a matching undersize connecting rod or one with bearing inserts installed. Or the crank journal can be reground until it's perfectly round again, and if the old connecting rod isn't severely scored or burnt, it can be resized to fit the odd-size reground journal. This would save money from having to purchase a high-dollar undersize connecting rod or it's useful for engines when a new replacement undersize rod is no longer available. The rod would still be strong and should last a long time, too. (As long as the engine isn't revved too fast or ran out of oil.)

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. There's lots of tricks that can be used to rebuild an engine. The rebuilt engine should last a long time, too.

Now move to the valves. To test for leaking valves, with the cylinder head removed and the piston at TDC on the compression stroke (both valves fully closed), apply Liquid Wrench (spray) or WD-40 around each valve and then use [150± psi] compressed air to blow through the exhaust and intake ports. Wrap a rag around the air nozzle and place it snug against the port so full air pressure will be against the valve. If bubbles form around the valves when applying the air pressure, this means that the valves are leaking and a professional valve job is required.

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.

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 mic'd (precision measured with a micrometer) to determine if it's excessively worn. If it is worn, it can be reground to .010" and a .010" undersize connecting rod can be used or the original rod can be bored for installation of .010" bearing inserts. But if it 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". If the cylinder is worn beyond for installation for a .030" piston/rings assembly, it will need to be sleeved for installation of a STD size piston/rings assembly. 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.

And if you're wondering, the model K141 (6¼hp) engine has a bore diameter of 2-7/8". The model K161 (7hp), which replaced the K141, has a bore of 2-15/16". It use the same piston/rings assembly as the model K181 (8hp) engine. Pistons/rings assemblies are no longer available in the 2-7/8" size. When rebuilding a K141, the cylinder must be bored for use with a 2-15/16" piston/rings assembly, which will then make it a model K161. The connecting rod and crankshaft are the same in the K141 and K161, but is different in the K181.

The following specialty tools are required to disassemble and reassemble a Kohler engine. Most of these tools are available at auto parts stores and on eBay.
  • Valve spring compressor
  • Cylinder hone (if cylinder need not be bored)
  • Piston ring compressor
  • Two torque wrenches that reads in inch and foot pounds
  • Quality-made automotive harmonic balancer puller to remove the flywheel
  • Valve Lapping tool and valve lapping compound
  • Feeler gauge to set the valve clearance, crankshaft end-play and camshaft end-play
  • 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 bearing inserts; recut or reground the valves and seats; 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.


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 bearing inserts isn't available, have it reground undersize (to wherever it "cleans up") and resize the connecting rod for proper fit.

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.

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 here if you're interested in having this service performed.


Don't Be A Slob When Rebuilding An Engine!

Always be professional whenever you rebuild an engine! Before assembling a fresh engine, always take the time to provide a neat and absolutely clean work environment. Make sure that your repair table or bench is sturdy enough to support the weight of a fully assembled cast iron bock Kohler engine. And make sure that your tools, shop/business towels, engine parts and hands are clean, too. Don't allow any dust or 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 help 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 bit of dirt inside an engine will "grind away" at the internal parts when the engine is in operation, causing unnecessary and expensive wear.

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.

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 at 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.


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 an Engine "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 more air (and fuel) in the combustion chamber(s), which builds up more air pressure (higher compression), which in turn allows the engine to produce more power and 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.


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 -

How to Remove Only the Crankshaft from a Kohler Engine -

  1. 10hp-18hp Kohler crankshaftRemove the flywheel and anything that's on the PTO end of the crankshaft.
  2. Remove the cylinder head.
  3. Remove the oil pan.
  4. Remove the piston/connecting rod assembly from the engine block.
  5. Remove the bearing plate.
  6. Finally, being very gentle, bump the PTO end of the crankshaft with a 2 lb. brass head hammer or a 2-3 lb. steel hammer and wooden block to remove it from the engine block.
  7. And if an engine originally came with balance gears, there's no need to reinstall them. They're made of out of balance cast iron material, they serve very little purpose and they may break, possibly destroying the engine block.

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

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

When regrinding a journal, and if a STD size journal is not worn past .005" on the low side or on the "flat spot," then the crank grinder person can regrind it "centered" to 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 can "cheat" and regrind the journal to the next undersize by offsetting the journal .006" or more in the lathe and regrind it to .010". 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" to .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 higher 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...

  1. Make sure the grinding stone is precision balanced, then true it up so it won't leave skip marks on the journal.
  2. On a single cylinder crankshaft, clamp one of the main journals in the first chuck, then clamp the other main journal in the second chuck to make sure the crankshaft is perfectly centered in the first chuck, then loosen the second chuck and move it away from the crankshaft.
  3. If it's a multiple journal crankshaft, perform the above with the crankshaft firmly clamped in both chucks.
  4. Firmly tighten the chuck(s).
  5. Relocate the first chuck (for a single cylinder crankshaft) or relocate both chucks (for a multiple journal crankshaft) off-center according to the crankshaft's stroke.
  6. Set up the dial indicator, and position it's lever on the #1 journal.
  7. Rotate the crankshaft slowly by hand until the lowest area on the journal shows on the dial indicator and then zero in the dial indicator.
  8. Relocate the first chuck (for a single cylinder crankshaft) or relocate both chucks (for a multiple journal crankshaft) off-center according to the crankshaft's stroke.
  9. If it's a multiple journal crankshaft, position the steady rest in the center main journal to prevent flexing of the crankshaft when grinding.
  10. IMPORTANT! 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 digital micrometer (a dial or digital caliper 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 to STD size again, or to the undersize of the other journals. But welding a journal and then regrinding it can be very expensive! And the crankshaft's stroke may not be the same.
  11. Back the stone away, and finish polishing the journal with a crankshaft polisher. The polishing process will remove the roughness of the grinding stone and about .0001" of metal until the journal is within specs.

IMPORTANT! The standard (STD) size rod journal (crank pin) on Kohler's K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp) and K341/M16 (16hp) flatheads, K361 (OHV 18hp) 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 yard work 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:

But when having a worn rod journal reground for an engine that's going to run at higher rpms or at wide open throttle for pulling competition, 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:

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, a .010", .020" or even a .030" undersize bearing can be used with no problem. Myself and many other pullers use undersize bearings in our pulling tractors, and I have no problems with the crank journal wearing. Heck, I've been using a .020" undersize bearing 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. 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 either 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 rpms 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.

Advertisement:
If you need any of the services performed or items listed below Ê, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
Crankshaft Repairs -
  • Remove burnt aluminum and polish journal to shiny finish. $10.00 each journal. I chuck the crankshaft in my big metal lathe, turn it on slow and use my crankshaft polisher with a narrow sanding belt to remove light burnt aluminum. This works great until the aluminum is gone, but sometimes the journal is scored or worn. Then it requires 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.
  • Regrind journal (crank pin) to next undersize. $60.00 per journal. Note: Kohler crankshafts can be reground to .030" undersize and still be safe to use with matching undersized bearing inserts installed in the connecting rod. And all crankshafts, rather if they're automotive or small engine, are checked for straightness before grinding. If they're bent or twisted, sometimes they can be straightened. We also do offset crankshaft grinding to increase the length of the stroke at no extra charge.
    • Once installed and in operation, there is no warranty or guarantee of any kind on crankshaft regrinds.
  • 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, and then the connecting rod can be resized so it'll fit the smaller undersize journal. 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. The cost for having this done is $100.00 labor for a single cylinder engine, and $200.00 for a two cylinder engine, plus return shipping & handling. If you're interested, we will need your crankshaft and connecting rod(s). An innovative concept by Brian Miller, because nobody else advertise this service.
    • Once installed and in operation, there is no warranty or guarantee of any kind on crankshaft regrinds.
  • 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 NF threads in the PTO end of the crankshaft for bolt and flat washer. $25.00.
Reconditioned OEM Kohler Crankshafts - [When available.]

Available for Kohler engine models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) or K361 (18hp OHV). These cast iron cranks are genuine Kohler, used and in excellent condition. They have either a 1" or 1-1/8" diameter x 3-1/2" long keyed PTO shaft. They have good gear teeth and may have a worn or unworn connecting rod journal in either STD size or undersize. Which can be reground to .010", .020" or .030" undersize. Although .030" is rare, it's still very safe to use. FYI - To be honest, these are old, used crankshafts. So if you need one with an unworn STD size rod journal, you'd probably have just as good a chance of winning the lottery than finding a used Kohler K-series or Magnum single cylinder crankshaft with an unworn STD size journal. And if you're going to use a pulley, clutch, etc., on the PTO end, then I will need to know the exact dimensions of the PTO end on your crankshaft so I can match it to one that I may have in stock. For accuracy, measure the length from the oil seal shoulder out. If you know your engine's exact model and specification numbers, go to kohlerplus.com (requires Microsoft Internet Explorer), to find the correct part number for the crankshaft, and then find the dimensions and specifications of the crankshaft is here: CRANKSHAFT REFERENCE MANUAL. (Requires Adobe Acrobat Reader and use Google Chrome web browser for a faster download of web sites with large files.)

  • K241/M10 (10hp) $100.00 each, plus shipping & handling.
  • K301/M12 (12hp) $125.00 each, plus shipping & handling.
  • K321/M14 (14hp), K341/M16 (16hp) and K361 (18hp OHV) $150.00 each, plus shipping & handling.
  • NOTE: Once installed and in use, there is no warranty or guarantee of any kind on any crankshaft purchase!
Main Crankshaft Radial Ball Bearings for Kohler K-series and Magnum cast iron block engine models K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp). 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. x 2.44" o.d. x .62" width. See note below Ê. NOTE: If yours have more than .005" of play (wear), then it needs to be replaced. Kohler part # 231625-S.
  • New aftermarket. Our part # 150-960. Same quality as OEM Kohler. $15.00 each, plus shipping & handling.
  • New OEM Kohler part. $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 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) and K361 (18hp OHV). Heat treated. These are specifically designed to provide maximum performance through precise ball implement selection. Aftermarket bearing packed with fresh grease from the factory. Good for general yard and garden or high-performance use. At high rpms or at wide open throttle, bigger balls run cooler which create less rolling resistance than a bearing with smaller balls. Dimensions: 1.57" i.d. x 3.54" o.d. x .90" width. See note below. Ê NOTE: If yours have more than .005" of play (wear), then it needs to be replaced. Kohler part # 235376-S.
  • Used and in excellent condition with little to no wear. (OEM Kohler.) $10.00 each, plus shipping & handling. (When available.)
  • New aftermarket. Our part #150-973. Same quality as OEM Kohler. $20.00 each, plus shipping & handling.
  • New OEM Kohler part. $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 NutAll-metal self-locking flywheel retaining nuts for threaded stud on end of K-series and steel crankshafts. Guaranteed to stay tight! IMPORTANT: Apply thin coat of motor oil on threads of crankshaft before installing nut then torque each at 65 ft. lbs.
  • 5/8" diameter, fine thread (5/8-18 NF). Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling.
  • 3/4" diameter, fine thread (3/4-16 NF). Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling.
Flywheel retaining bolt for threaded hole in end of crankshaft. Each are grade 8, 1-1/2" long. Torque at 40 ft. lb. Replaces Kohler part # 25 086 253-S.
  • 3/8" diameter, fine thread (3/8-24 NF). $1.00 each, plus shipping & handling.


Flat washer for retaining flywheel or aluminum clutch hub to flywheelExtra Thick Steel Washers for retaining flywheel and/or Cub Cadet aluminum clutch adapter hub to flywheel (a must to prevent hub breakage!), or use as a safety washer w/grade 8 bolt on PTO end of crankshaft.

  • Washer with 3/8" diameter hole x 1-1/4" o.d. x approximately 1/4" thick. Replaces Kohler part # 12 468 03-S. $3.00 each, plus shipping & handling.
  • Washer with 5/8" diameter hole x 1-1/4" o.d. x approximately 1/4" thick. Replaces Kohler part # X-25-76, X-25-104. (Discontinued from Kohler.) $3.00 each, plus shipping & handling.
  • Washer with 3/4" diameter hole x 1-1/4" o.d. x approximately 1/4" thick. Replaces Kohler part # X-25-71, X-26-10. (Discontinued from Kohler.) $3.00 each, plus shipping & handling.
Steel Adapter Step-Washer for mounting Cub Cadet aluminum clutch hub with 5/8" center hole to Kohler Magnum crankshaft with a 3/8" bolt. A must to center hub and prevent hub breakage! $8.00 each, plus shipping & handling.
Steel Rectangular Flywheel Key for early Kohler K-series engine models K241, K301, K321 with the 8" diameter flywheel. Dimensions: 3/16" wide x 1/4" tall x 1-3/8" long. OEM Kohler part # X-366-1-S.
  • Used. $1.00 each, plus shipping & handling. (When available.)
  • New. $2.25 each, plus shipping & handling.

Aluminum Rectangular Flywheel Key for Kohler K-series engine models K141, K160, K161, K181, K241, K301, K321, K341, K361 and Magnum M8. Made of 6061 alloy; medium-grade hardness aluminum. Dimensions: 3/16" square x 1-3/8" long. Replaces Kohler part # X-366-1-S.

  • $5.00 each, plus shipping & handling.

Steel Square Flywheel Key for Kohler K-series engine models K141, K160, K161, K181, K241, K301, K321, K341, K361 and Magnum M8. Dimensions: 3/16" square x 1-3/8" long. Kohler part # X-286-17-S.

  • Aftermarket. $1.00 each, plus shipping & handling.
  • OEM Kohler part. $1.50 each, plus shipping & handling.

Aluminum Square Flywheel Key for Kohler K-series engine models K141, K160, K161, K181, K241, K301, K321, K341, K361 and Magnum M8. Made of 6061 alloy; medium-grade hardness aluminum. Dimensions: 3/16" square x 1-3/8" long. Replaces Kohler part # X-286-17-S.

  • $5.00 each, plus shipping & handling.

Steel Woodruff Flywheel Key for early Kohler engine models K160, K161, K181 and later 10-16hp K-series and all Magnum engines. 3/16" wide x 1" long. Kohler part # X-46-3-S.

  • Aftermarket. $1.00 each, plus shipping & handling.
  • OEM Kohler part. $1.50 each, plus shipping & handling.


About Crankshafts Breaking at High RPMS -

A cast or billet steel crankshaft should survive as high as 7,000 rpms for a long time if they've been precision-balanced to the connecting rod and piston assembly. 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 rpms. When they flex, this 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 rpms, 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.


If a stock engine runs with a "hunting" sound, and the governor lever moves side to side while running at around 3,600 or 4,000 rpms, and if adjusting the carburetor or adjusting the rpms doesn't fix the problem, then perhaps the governor gear/flyweights assembly is worn on its stub shaft, or the shaft itself is worn. This will cause the governor gear to wobble around on its shaft, which will cause the governor to oscillate. And the engine will run erratic. To fix this problem, the governor gear and shaft must be replaced with new ones, or a cast iron governor gear. (Nylon governor gears are known to wear more often than cast iron ones.)

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

  1. Remove the internal parts of the engine (mainly the crankshaft and camshaft).
  2. Remove the governor gear retaining screw (the Phillips head screw that's on the outside of the block).
  3. The governor gear can now slide off the stub shaft.
  4. IMPORTANT! If the engine is going to be rebuilt and the block thoroughly cleaned, be sure to remove and save the small thrust washer that's on the governor gear's stub shaft! This special washer is made of either hardened steel or bronze for durability. A lot of people are not aware of this washer and it usually falls out of the block and gets lost while cleaning inside the block.
  5. Install the new governor gear assembly in reverse order of removal.

How to Replace a Worn Governor Stub Shaft (Governor Pin) in a 6¼hp-16hp Kohler Engine -

  1. Remove the governor gear as described above È.
  2. Remove the cam gear cover and through the cover opening, use a 5/16" steel rod with a blunt end and medium size hammer to drive the welch plug from the block.
  3. Going through the welch plug hole opening, use a 5/16" steel rod with a concaved end (depressed center) and medium size hammer to drive the stub shaft from the block.
  4. Fabricate a driver from a 5/8" diameter solid steel rod having a 3/8" diameter x 3/8" deep drilled hole in one end to install the new stub shaft in the hole. Allow the stub shaft to extend 3/8" from the block.
  5. Place the welch plug over a 7/8" socket and use the hammer to depress the center so the plug will become concaved (depressed center).
  6. Apply Clear RTV Silicone Adhesive Sealant around the welch plug counterbored hole and install the welch plug in the hole with the depressed center facing upward. Use the hammer to flatten the welch plug so the diameter will expand and fit tight in the counterbore hole. By the way - I've always preferred to use Clear RTV Silicone Adhesive Sealant for two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen between the parts.

Nylon VS Cast Iron Governor Gear Assemblies -
The most popular Kohler governor gear assembly nowadays for competition stock garden tractor pulling are the ones that's made of cast iron. These are no longer made or available from Kohler or any other source. They were used in the 4hp, 6¼, 7hp, early 8hp, early 10hp and 12hp K-series Kohler engines 'til the late 1960s. It's impossible to tell if an engine has a metal governor gear by looking at it from the outside. The only way of knowing for sure is remove the oil pan and look at it from inside.

There's really nothing special about the cast iron governor gear, except when the governor linkage is disconnected, they can withstand very high rpms and won't explode (break apart) like the nylon governor gears sometimes do. The reason the cast iron ones are so popular nowadays among stock pullers is because some pullers like to compete in two separate classes, one class that has an engine rpm limit of around 4,000± and another class with a higher rpm limit, or open rpm.

Consider this: The governor gear spins 1.25 times faster than the crankshaft. This means at 4,000 rpm, the governor gear spins at 5,000 rpm. At 6,500 rpms, it spins at 8,125 rpms! And when using a nylon governor gear, don't worry, as long as the governor linkage is adjusted correctly, it should hold up just fine in an engine that will never operate above 4,000 rpm.

The cast iron governor gear will fit all Kohler K-series and Magnum 4hp-16hp flatheads, 18hp K361 OHV single cylinder cast iron block and the KT-series and Magnum flathead twin cylinder engines.

Plastic governor gear


Cast iron governor gear

Advertisement:
If you need any of the parts listed below Ê, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
Nylon Governor Gears. Good for up to 4,000 rpm. OEM Kohler part # A-235743-S.
  • Used and in excellent condition. $20.00 each, plus shipping & handling. [When available.]
  • New. $39.50 each, plus shipping & handling.
Cast Iron Governor Gear. Good for above 4,000 rpm up to wide open throttle. Will not explode or flex at high rpms like the nylon governor gears sometimes do. OEM Kohler part # A-237031. (Discontinued from Kohler.)
  • Used and in excellent condition. $60.00 each, plus shipping & handling. [When available.]
Governor Gear Stub Shafts for Kohler engine models K141 (6¼hp), K160 (6.6hp), K161 (7hp), K181/M8 (8hp). Dimensions: 3/8" diameter x .625" long. Each is press-fit into block. Kohler part # 230125-S.
  • Aftermarket. Precision ground, heat-treated alloy steel. $10.00 each, plus shipping & handling.
  • OEM Kohler part. $22.05 each, plus shipping & handling.

Governor Gear Stub Shafts for Kohler engine models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp), K361 (18hp OHV) and all KT-series & Magnum twin cylinder flathead engines. Dimensions: 3/8" diameter x .815" long. Each is press-fit into block. Kohler part # 235125-S.

  • Aftermarket. Precision ground, heat-treated alloy steel. $10.00 each, plus shipping & handling.
  • OEM Kohler part. $46.15 each, plus shipping & handling.
New hardened steel thrust washer for nylon or cast iron governor gears. Kohler # 237022-S.
  • Aftermarket. $2.00 each, plus shipping & handling.
  • OEM Kohler part. $3.70 each, plus shipping & handling.
Governor Cross Shafts for Kohler engine models K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp). New shaft includes thrust washer. The lever on these rarely break. NOTE: Before installing, apply clean motor oil 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 Thrust Washer for governor cross shaft above È. Kohler part # X-25-58-S.

  • Aftermarket. .50¢ each, plus shipping & handling.
  • OEM Kohler part. $1.90 each, plus shipping & handling.


Governor Cross Shafts for Kohler engine models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) flatheads, K361 (18hp OHV). New shaft includes steel thrust spacer. NOTE: Before installing, apply clean motor oil on shaft for smooth governor action and less wear to shaft and/or bushing. 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. $24.60 each, plus shipping & handling.
  • New and welded. $30.00 each, plus shipping & handling.

Steel Thrust Spacer for governor cross shaft above È. Kohler part # 25 112 17-S.

  • Aftermarket. $1.00 each, plus shipping & handling.
  • OEM Kohler part. $4.50 each, plus shipping & handling.
Bronze Governor Shaft Bushing for all Kohler engine models K90 (3.6hp), K91 (4hp), K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181 (8hp) w/spec # 30100-30848 and various M8 (8hp) engines with V-shaped/coiled governor spring under bushing. NOTE: When ordering, please specify engine model and specification numbers. And before installing bushing, apply clean motor oil on shaft for smooth governor action and less wear to shaft and/or bushing. OEM Kohler part # 230476-S.
  • $10.00 each, plus shipping & handling.

Bronze Governor Shaft Bushing for Kohler engine model K181 (8hp) w/spec # 301000-301045, and various M8 (8hp) engines with extension governor spring. NOTE: When ordering, please specify engine model and specification numbers. And before installing bushing, apply clean motor oil on shaft for smooth governor action and less wear to shaft and/or bushing. OEM Kohler part # 41 158 02-S.

  • $6.30 each, plus shipping & handling.

Bronze Governor Shaft Bushing for all Kohler K-series and Magnum engine models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) and K361 (18hp OHV). NOTE: When ordering, please specify engine model and specification numbers. And before installing bushing, apply clean motor oil on shaft for smooth governor action and less wear to shaft and/or bushing. OEM Kohler part # 235476-S.

  • $7.50 each, plus shipping & handling.

Bronze Governor Shaft Bushing with Neoprene Rubber Seal installed in machined counterbore to keep dirt out (which wears the bushing) and prevent oily mess on side of engine. Seal fits snug on shaft and in bushing, and has no effect with operation of governor whatsoever. For Kohler engine models above È with bushing # 230476-S, 41 158 02-S or 235476-S. NOTE: When ordering, please specify part number of bushing or engine model and specification numbers. And before installing bushing, apply clean motor oil on shaft for smooth governor action and less wear to shaft, seal and/or bushing. An innovative concept by Brian Miller, because nobody else advertise this part.

  • Machined bushing with seal. $20.00 each, plus shipping & handling.


IMPORTANT! IMPORTANT! NEVER USE GASOLINE OR A HIGHLY FLAMMABLE LIQUID TO CLEAN YOUR PARTS! Gas cleans good, but it's extremely flammable, making it too dangerous to handle. The best (and safest) way to clean an engine block and its parts for rebuilding is to wash all parts with cleaning solvent (or mineral spirits, also known as paint thinner). Paint thinner is also known as or can be used as cleaning solvent for oily or greasy engine or mechanical parts. Personally, I've always used paint thinner to clean my engine parts.

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 the paint also. So it's best to use it on bare metal or parts that need repainting.

For stubborn or caked-on grime, use a heavy duty oven cleaner, such as EASY-OFF® or equivalent. (Use the fume-free brand so you can breath.) Just spray the parts thoroughly, let set for 30-45 minutes, then blast the grime and debris off with a high pressure water washer. Pressure from an ordinary garden hose just won't cut it. After cleaning, blow dry the parts and be sure to coat the bare metal with oil so they won't rust. If oven cleaner won't work, take the cast iron and steel parts to an automotive machine shop and have them "hot tanked" and have the aluminum parts sandblasted. I don't suggest sandblasting cast iron engine blocks or related parts because some of the sand can become lodged inside the engine and come loose when the engine is in operation, causing severe internal engine wear. Personally, I just coat the parts with oven cleaner and then blast the dirt off with my 1,000 psi water pressure washer.

Paint thinner can also be used to dry motor out oil that's spilled on a concrete floor. Just pour some thinner on the oil, use an old broom to thoroughly mix the thinner with the oil, and eventually, the oil will dry with no signs of it ever being on the floor.

How to Remove Surface Rust from a Cast Iron Engine Block or Cylinder Head -

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 blast it off with my 1,000 psi water pressure washer. The rust and grime comes right off!


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 porting/polishing the intake and exhaust 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:


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 here for information regarding E-85 fuel. The above È figures was computed using Mr. Gasket's DeskTop Dyno computer application. (Do a search on the Internet for this application.) 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 here for references to various compression ratios. After modifications have been made, the increase in power will definitely be noticeable!

For pulling competition 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 here to learn how to do this.

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If you need your crankshaft and piston/rod assembly and/or flywheel precision dynamically balanced, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.

Precision, Dynamic Spin-Balancing Service -

  • Balance flywheel (steel or cast) - $50.00 labor, plus return shipping & handling. & handling..
  • Balance cast crankshaft - $125.00 labor (mallory extra), plus return shipping & handling. To balance an engine, we will need the crankshaft, piston/rings, pin, clips, connecting rod and bearing inserts. The flywheel is balanced separately.
  • Balance steel crank - $150.00 and up (mallory extra), plus return shipping & handling.

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.

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 allows the engine to run at 3,600 rpm.

A nylon governor gear 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. 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 to lighten them will improve engine performance, well, first of all, the flyweights are made of extremely hard material for obvious reasons. I tried, and 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 in engine performance whatsoever. All it'll do is allow the engine to rev up more, that's all.

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 (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 governor spool from 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 you need even more power, remember the old saying? "There's No Substitute for Cubic Inches!"

If you're running a 10hp (K241) Kohler engine in a class that allows up to a 12hp engine, there's no need to go out and acquire a 12hp 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 12hp piston assembly, a 12, 14, 16 or 18hp connecting rod, and a 12hp crankshaft.

NOTE: Some 10hp Kohler engine blocks have K301 embossed in the casting on the PTO end. These blocks have a thicker cylinder wall and can be safely bored for a 12hp piston (even up to .030" oversize), without making the cylinder wall too thin. They cannot be bored for a 14hp piston though.

The K301 blocks with a 10hp bore can be safely bored for use with a 12hp piston. The K301 blocks are actually a 12hp 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 12hp 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 12hp piston assembly (3.375" STD size bore) and therefore, are a 12hp 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 25.7, 27.7, 31.6 CID Engine or a Hybrid Kohler Engine Model K261, K281 or K321 - An innovative concept by Brian Miller, because nobody else advertise this.
To create a 25.7, 27.7, 31.6 CID engine or a hybrid Kohler engine model K261, K281, K321, use a K301/M12 (12hp), K321/M14 (14hp) or K341/M16 (16hp) engine block and piston/rings assembly respectively, a stock K241/M10 (10hp) connecting rod or a 5.558" (10hp) billet rod with a 1.500" journal hole, and a K241/M10 (10hp) crankshaft. This will create a de-stroked 12hp, 14hp or 16hp Kohler engine. The model K261 will use a 12hp block; the K281 will use a 14hp block and the K321 will use a 16hp block.

If the K261 is built to the max at 4,000 rpm with reworked stock size valves, ported, quality performance torque cam and a bored-out 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 1.2" carburetor, it'll produce about 26hp at 7,500 rpms and 22 ft. lb. of torque at 6,000 rpm.

If the K281 is built to the max at 4,000 rpm with reworked stock size valves, ported, quality performance torque cam and a bored-out 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 1.2" carburetor, it'll produce about 30hp at 7,000 rpms and 25 ft. lb. of torque at 6,500 rpm.

If the K321 is built to the max at 4,000 rpm with reworked stock size valves, ported, quality performance torque cam and a bored-out 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 1.2" carburetor, it'll produce about 36hp at 7,500 rpms 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 10hp rod will need to be enlarged to exactly .8755" for use with the 12hp, 14hp 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 10hp crankshaft so the rotating assembly will be properly balanced. Click here to learn how to statically balance an engine.
  • 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 27 CID Engine or a Hybrid Kohler Engine Model K271 (Stroker 10hp Engine) - An innovative concept by Brian Miller, because nobody else advertise this.
To create a 27 CID engine or a hybrid Kohler engine model K271, use a K241/M10 (10hp) block with a 10hp piston/rings assembly, a 12hp, 14hp, 16hp [flathead engine] connecting rod, an 18hp OHV ALCOA rod or a 5.7" billet rod, and a 12hp, 14hp, 16hp flathead or an 18hp OHV engine crankshaft. This combination will create a 27 cubic inch engine, a 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 (10hp) 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 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" 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.
  • Giving an engine a longer stroke will gain an edge over the competition. Click 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 Build a 30 Cubic Inch (NQS Outlaw) Pulling Engine -
To build a "somewhat" competitive 30 cubic inch pulling engine, acquire a newer 12hp 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" long 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" in 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" in 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" in 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.

But to build a truly competitive 30 c.i. pulling engine, use a 10hp/K241 Kohler block. (Acquire a 10hp block with K301 embossed on the PTO end, for strength and durability, like the one pictured above È.) The cylinder will need to be bored to 3.300" and a steel crankshaft with a stroke of 3.500" will need to be used to build a stroker 29.94 cubic inch engine. (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" long 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" in 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" in 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" in 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.

Due to the small bore and long stroke, this combination produces more torque (lugging power) at high rpms (wide open throttle) than building a 12hp 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 here for an explanation of why a longer stroke works better.

The NQS Outlaw 30 Cubic Inch Pulling Engine -
A "somewhat" competitive 30 cubic inch pulling engine is when a newer model 12hp Kohler block having a large intake port, the cylinder to be bored to .050" oversize for a 3.425" aftermarket (J&E or Arias) piston/rings assembly, and a stock stroke (3.250") crankshaft. This bore and stroke combination calculates to 29.94 c.i. A 1.8" offset intake valve and a 1.5" offset exhaust valve, .533" steel cam, billet head, and use a 44mm Mikuni carburetor with about an 8" long extension should be used.

But a truly competitive 30 c.i. pulling engine is when a 10hp/K241 Kohler block is used. For strength and durability, especially if it's built to the max, it's best to use a 10hp block with K301 embossed on the PTO end, like the one pictured above È. This particular block have an extra thick cylinder wall. The cylinder will need to be bored to 3.300" and a steel crankshaft with a stroke of 3.500" will need to be used to build a stroker 29.94 cubic inch engine. Install the same size offset valves, cam, carburetion and head as above È.

Because of the smaller bore and longer stroke, the combination above È will produce more torque at high rpm (wide open throttle) than the 12hp block with a .050" overbore and stock stroke (3.250") crankshaft. Either engine can use the same size offset valves, camshaft, carburetion and head. If the engine is built right, and if the tractor is set up right, it'll give the competition a kick in their butt! No joke.

This smaller bore and longer 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 at 29.94. But to be closer to 30 cubic inches, a STD size [steel stroker] crank journal can be reground .015" offset, resulting in a .030" undersize journal, lengthening the stroke to a maximum of 3.5075". The results with the 3.300" bore and a longer 3.5075" stroke, the cubic inches will be at 29.999, which is just under the legal limit. Doing this will gain slightly more of an edge over the competition. Click here for an explanation of why a longer stroke works better.

How to Create a 38.3 or 40.8 CID Engine, or a Hybrid Kohler Engine Model K381 or K411 - An innovative concept by Brian Miller, because nobody else advertise this.
This is considered "old school technology" by today's standards, but it still works great, and if the engine is built right, it should be very competitive for pulling. Plus, these type of engines are economical to build. Anyway, a 38.3 CID hybrid engine requires that a STD size (3.875") 307 Chevrolet OEM-type cast piston, rings and wrist pin be used. And the 40.8 CID hybrid engine requires that a STD size (4") 327 Chevrolet OEM-type cast piston, rings and wrist pin be used. To create either engine, besides the piston/rings assemblies, the other parts needed are:
  • K341/M16 (OEM Kohler part # 45 067 24-S), K361 ALCOA or 5.3" billet connecting rod.
  • K321 (14hp), K341 (16hp) or K361 (18hp OHV) stock stroke crankshaft.
  • 12 (or 13) fin K341/M16 (16hp) Kohler engine block for the 38.3 CID engine, or 13 fin K341 (16hp) block for the 40.8 CID engine.

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 (1968-1973) and 327 (1962-1969) piston, rings and wrist pin are available at most auto parts supply stores. Coincidentally, the 307 and 327 Chevy 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 1.2" carburetor, it'll produce about 28hp and 37 ft. lb. of torque at 4,000 rpm. But if built to the max at wide open throttle with reworked stock size valves, enlarged intake and exhaust runners, a big performance cam and a bored-out 1.2" carburetor, it'll produce about 32hp at 5,500 rpm and 34 ft. lb. of torque at 5,000 rpm. And if built to the max at wide open throttle with a reworked (Chevy) 1.94" offset intake valve and (Chevy) 1.5" centered exhaust valve, enlarged intake and exhaust runners, a high-performance cam, and a bored-out 1.2" carburetor, it'll produce about 52hp at 7,500 rpm and 39 ft. lb. of torque at 6,000 rpm.

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 1.2" carburetor, it'll produce about 30hp and 39 ft. lb. of torque at 3,500 rpm. But if built to the max at wide open throttle with reworked stock size valves, enlarged intake and exhaust runners, a big performance cam and a bored-out 1.2" carburetor, it'll produce about 36hp at 6,500 rpm and 34 ft. lb. of torque at 5,000 rpm. And if built to the max at wide open throttle with a reworked (Chevy) 1.94" offset intake valve and (Chevy) 1.5" centered exhaust valve, enlarged intake and exhaust runners, a high-performance cam and a bored-out 1.2" carburetor, it'll produce about 56hp at 7,500 rpm and 43 ft. lb. of torque at 6,000 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 bigger piston.
  • Fill in the valve reliefs in either piston with aluminum welding for higher compression, then grind or machine the weld flat. Leave the notch untouched.
  • 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 wrist pin.
  • The Chevy wrist pin for either piston will need to be ground narrower to clear the snap rings when installed.
  • CORRECTION! The 307 and 327 OEM-type cast pistons have a compression height of 1.654". The Kohler K341 and K361 pistons have a compression height of 1.7", resulting in a difference of .046".
    • For either Chevy piston to come flush with the top of the block at TDC, the big hole in the [Kohler] connecting rod will need to be bored .046" offset toward the oil dipper for installation of bearing inserts. (Installation of bearing inserts in the [Kohler] connecting rod is highly advised for high rpm or at wide open throttle operation.) Or center-bore the [Kohler] rod for bearing inserts, and then being the [.875"] wrist pin hole will need to be enlarged exactly to .9275" for the 307 or 327 (.9274") wrist pin, bore the wrist pin hole .046" offset toward the top of the rod. Or if using a 5.3" billet rod (with bearing inserts), bore the wrist pin hole .046" offset toward the top of the rod. Either way should work fine.
    • For the piston to pop out of the cylinder .020", bore the big hole in the [Kohler] rod at .066" offset. Or for the same rod, bore the big hole .046" offset, and then bore the wrist pin hole .020" offset toward the top of the rod. Either way should work fine.
  • When installing either Chevy piston in the cylinder, due to the .060" offset wrist pin, the notch on the edge of the piston faces the flywheel end of the block.
  • IMPORTANT! Being a much heavier piston and rings assembly will be used, the crankshaft will definitely need to 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 smooth. The sides of the rod journal on the crank may need to be ground away too, to obtain proper balance. Click here to learn how to statically balance an engine.
  • If building this type of engine for competition pulling, check your club's sanctioning rules so this engine will be legal within its class!


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, 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 (10hp), K301/M12 (12hp) and K321/M14 (14hp) engine blocks have 13 cooling fins. Otherwise, there's really nothing else special about these blocks. Except for certain K-series K241 (10hp) 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.

The 12 and 13 fin 16hp Kohler blocks -

Here's something to think about: Between the factory-stock 12hp and 14hp 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, 12hp or 14hp 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 allows 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. 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 Pulling Competition -

Many people (pullers) believe that an engine will produce more noticeable power and torque simply by boring the cylinder and installing a maximum of .030" oversize piston/rings assembly. But there's no need to do this, and it won't give the engine anymore noticeable power. The best thing to do is just bore the cylinder to the next oversize, if needed. Or if it's worn beyond .030", have it sleeved back to standard size.

What makes an engine produce more noticeable power and torque is not necessarily a larger diameter piston, it's having a longer stroke. For example: there's a world of difference in power and torque between a 10hp Kohler engine into a 12hp Kohler engine. Unlike a strong 10hp, a healthy 12hp engine will actually pull you back in the seat when you punch the gas. This 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! 12hp engines are able to produce 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. Many new automotive engines nowadays have a small bore and long stroke. Simply because it works better!

A longer-than-stock stroke works better for more engine torque because at very high rpm (wide open throttle), it takes less time for the flame front (combustion) to travel down in the cylinder than it would to travel across the top of the piston. Therefore, due to the longer stroke, the fuel burns more thoroughly and the engine produces more power from the expanding gases of the burning fuel. For pulling competition, on a short stroke engine, at very high rpm and when the engine is under a load, some of the fuel will go unburned [out the exhaust] and loss of power will result. A short stroke engine works best for racing, but not for pulling. Racing engines and pulling engines are not built on the same principles. Racing engines require horsepower (speed) and pulling engines require torque (lugging power). This is why some "cheaters" in pulling run an illegal stroker engine in a class when they're not supposed to. As a result, on a biting track, when all the legal engines have run out of power, the stroker engine will keep lugging on out the gate. This is true for all engines, despite if it's a gas/alcohol burner, Diesel, 2- or 4-cycle. Return to previous paragraph È

If your club's rules allows 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:

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 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 10hp block can be bored to use a 12hp piston and a 12 hp block be bored to use a 14hp 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 12hp 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 recommended that the cylinder be "strapped" to 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).

When burning methanol fuel, with a thin cylinder wall, and if the cylinder isn't securely strapped 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.

Moreover, if you had a 10hp block bored for a 12hp piston, or a 12hp 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.

Details of the Cylinder Restraint SystemPersonally, I don't fasten All Thread rods directly into the block or bearing plate to strap the cylinder. I've seen where some engine builders do that. I found that it's much easier just to use two light-weight 1/8" x 1" flat pieces of welded-together upside-down "T" shaped steel brackets. I fasten one bracket using the two upper bolts against the bearing plate so the bracket will clear the raised ridges on the plate, and the other bracket is installed on the PTO end of the block, and then I weld the threaded rods to them. This setup is easier to remove and reinstall when it comes time to freshen the engine. I think it works great and looks good, too.

And it's doubtful if a 14hp block can be bored for use with a 16hp piston. Some people have done this with success. But the center of the outer part of the cylinder may 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. If attempting this, it'll be a good idea to install a head strap rather it's for competition pulling or general yard use.

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.

"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 minimum 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 and/or due to extremely high compression. Position the strap directly over (center of) the cylinder and not over the valve area.

And if there's no bolt holes on the PTO side of the block, then the block can be safely drilled and tapped on the PTO side for a head strap. Just be sure to drill the holes where there's most metal so you won't get into the crankcase. Torque the studs to 10 ft. lb. each.


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...

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 requires that the lower end of the cylinder be ground away on each side for clearance of the wider rod. If performed correctly, this will not interfere with the stability of the piston whatsoever. But if it's a pretty wide missing chunk, and you have doubts about the stability of the piston, then perhaps the block needs to be sleeved. Before installing the sleeve, the cylinder is made bigger with a boring bar. If performed correctly, the boring bar is adjusted so it won't cut away approximately 1/8" bottom portion of the cylinder. The missing chunk will not interfere with the boring process either. The boring bar machine is positioned firmly with the cylinder to prevent any slippage. As it bores the cylinder, it'll skip over the missing chunk and continue to bore the rest of the cylinder. Then after the sleeve is installed, it's honed for fitting of the piston and rings.

How to Install a Cylinder Sleeve:

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

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If you need to purchase a cylinder sleeve or the cylinder(s) sleeved in your engine block, contact Elson Nichols of Loop 70 Auto Parts and Machine, 14 Business Loop 70 East, Columbia, Missouri 65201. Phone: 1-573-449-0893. E-mail: vjnen@centurytel.net. He has many years of experience in engine machine work and he can professionally sleeve your block and then bore it for a STD size piston/rings assembly.


Maintain Proper Crankcase Vacuum So the Single Cylinder Engine Will Produce More Power!

Kohler's Crankcase Breather AssembliesThe job of the reed valve in the crankcase breather assembly is to prevent outside air (plus dust and dirt) from being drawn inside the crankcase. It also maintains crankcase vacuum so the engine will produce more power, and it prevents motor oil from being blown out (as long as the piston rings are in good condition). When reinstalling the reed valve/breather plate assembly on models K141, K160/K161, K181/M8, the reed valve faces outward. And on all Kohler engine models, the small hole faces downward, so any oil in the breather assembly will drain back down into the crankcase. And be careful not to block the oil drain hole when using Clear RTV Silicone Adhesive Sealant upon reinstalling. By the way - I've always preferred to use Clear RTV Silicone Adhesive Sealant for two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen between the parts.

The job of the [coarse] filter in the crankcase breather assembly is to trap oil vapors from exiting the crankcase (as long as the piston rings are in good condition), and it traps outside dust and dirt from entering the crankcase. It should be used only on engines where the crankcase is not filtered through the air filter assembly with a rubber tube (Quiet Line and Magnum models).

If clean motor oil has contaminated (clogged) a new or good pleated air filter, there's no need to discard the filter and purchase a new one. The oil can be dried out of the filter by soaking it in paint thinner (the thinner will mix equally with the oil), and then allow it to air-dry at room temperature overnight. As the paint thinner dries, the oil will dry out, too.

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 particles 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.

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 allows 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. When the piston goes down, air that's in the crankcase is forced out through the reed valve and cover hole, and when the piston goes back up, air wants to be drawn back in, 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 - an automotive PCV (Positive Crankcase Ventilation) valve can be substituted for the reed valve. But most pulling tractors don't really 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 in the crankcase and then out the breather. So it may time for a complete engine rebuild soon. 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 full synthetic motor oil for warm weather use.

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If you need any of the parts listed below Ê, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
Crankcase Breather Filter. Replace deteriorated filter and prevent dust and dirt from entering crankcase. Also traps oil vapors from exiting crankcase. Use on engines where the crankcase is not filtered through the air filter assembly with a rubber tube. Fits Kohler K-series and Magnum engine models K141, K160/K161, K181/M8, and twin cylinder engine models KT17, KT17II, KT19, KT19II, M18 and M20.
  • OEM Kohler part # 231419-S. $4.20 each, plus shipping & handling.
Small Crankcase Breather Filter. Replace deteriorated filter and prevent dust and dirt from entering crankcase. Also traps oil vapors from exiting crankcase. Fills about 1/3 area of breather plate. Use on engines where the crankcase is not filtered through the air filter assembly with a rubber tube. Fits older Kohler K-series engine models K241 (10hp), K301 (12hp), K321 (14hp), K330/K331 (12½hp), K341 (16hp), K361 (18hp OHV), and various Magnum models M12 (12hp), M14 (14hp) and M16 (16hp).
  • OEM Kohler part # 235118-S. $9.10 each, plus shipping & handling.
Large Crankcase Breather Filter. Replace deteriorated filter and prevent dust and dirt from entering crankcase. Also traps oil vapors from exiting crankcase. Fills entire area of breather plate. Use on engines where the crankcase is not filtered through the air filter assembly with a rubber tube. Fits various newer Kohler K-series 10-16hp and various Magnum engine models M10 (10hp), M12 (12hp), M14 (14hp) and M16 (16hp).
  • OEM Kohler part # 47 050 01-S. $5.60 each, plus shipping & handling.
Crankcase Breather Reed Valves. Replace damaged reed valve to prevent outside dust and dirt from entering crankcase and to maintain crankcase vacuum so engine will produce more power.

Reed Valve for Kohler K-series and Magnum engine models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) and K361 (18hp OHV).

  • OEM Kohler part # 235047-S. $9.10 each, plus shipping & handling.

Reed Valve and Plate Assembly for Kohler K-series and Magnum engine models K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp).

  • OEM Kohler part # 230066-S. $11.20 each, plus shipping & handling.
Crankcase Breather Neoprene Rubber Seals. Places pressure against reed valves above È to insure better crankcase vacuum.

Fits certain Kohler engine models: CH18, CH20, CH22, CH23, CH25, CH620, CH640, CH730, CH740, CV15, CV25, K141, K160/K161, K181/M8, MV18 and MV20.

  • OEM Kohler part # 230046-S. $3.10 each, plus shipping & handling.

Fits certain Kohler engine models: CH20, CV18, CV20, CV22, CV25, CV624, CV670, CV675, CV680, CV724, CV725, CV730, CV740, K241, K301/M12, K321/M14, K341/M16, MV16, M18, MV18, M20 and MV20.

  • OEM Kohler part # 231032-S. $4.20 each, plus shipping & handling.

Use an Auxiliary Crankcase Breather for Better Engine Venting Above 4,000 rpm...

The factory OEM crankcase breather alone isn't adequate for all high-performance single cylinder engines, especially big cubic inch engines running at all-out rpm. They build up more pressure in the crankcase due to the longer stroke and bigger piston. The downward movement of the piston will force air out of the crankcase. At very high rpm (well above 4,000 rpm), the small holes in the engine block and breather assembly sometimes 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 very high rpm, it will sometimes take some crankcase oil with it, spewing an oily mess on the track, and probably on the tractor. So if your engine has this problem (not all engines spew oil at high rpm), and to keep this from happening, your engine needs an auxiliary crankcase breather. It helps to relieve some of the air pressure inside the crankcase that's placed on the stock breather assembly. But by looking at the picture to the right, you'll notice that this is an open breather system with no one-way check valve to prevent air from re-entering the crankcase. Relax. This is how it works: the faster a single cylinder engine revs, the less time air has to exit and re-enter the crankcase. In other words, at very high rpm, and being air can be compressed as well as it can be expanded, 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. The auxiliary breather also has a filter in it. This is to prevent dust and dirt from entering the crankcase at low rpms. And the auxiliary crankcase breather doesn't help to make more horsepower. It just keeps oil inside the engine and off the track.

Advertisement: (posted 1/27/11)
If your engine needs an auxiliary crankcase breather kit, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.

For better engine venting and less oily mess above 4,000 rpm. Kit includes street elbow, short pipe fitting, 12" vinyl tubing, clamp and MOPAR breather. NOTE: For Kohler blocks, use a 3/4" NPT taper pipe tap to cut threads in the block to install the pipe fitting. For aftermarket blocks, use a 1" NPT taper pipe tap to cut threads in the block to install the pipe fitting. Sold below Ê.

  • Complete Auxiliary Crankcase Breather Kit. $30.00 each, plus shipping & handling.
  • 3/4" NPT taper pipe tap. Made of quality carbon steel. $21.00 each, plus shipping & handling. Part # WT0321-0025
  • 1" NPT taper pipe tap. Made of quality carbon steel. $27.00 each, plus shipping & handling. Part # WT0321-0030


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 to wear. New top and second piston rings have a square edge (actually, the second ring has a slightly "angled" edge), and they operate in a particular manner. The top ring holds the compression. The second ring is the oil scraper or oil control ring. The "angled edge" allows 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 edge on the rings to become rounded. When this happens, the second ring can't slide over the oil or scrape it back 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 it 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.

Speaking of a worn piston, if your engine makes an uneven "clattering" sound when running or especially when under a load, then perhaps the piston is loose or worn in the cylinder bore. To check this, 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 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 is left behind with burning of a fossil fuel. This is why it's so important to have a fine-tuned engine, so it'll leave behind very little carbon as much as possible.

According to Kohler's specs, 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 OEM pistons will wear slightly when used in a high rpm application. As for a forged, high-performance piston (Arias and J&E), when hot, they will swell more than an OEM piston. Therefore, requiring slightly more clearance. Most high-performance pistons require a .010"-.014" clearance. But check with the manufacturer of the piston for the exact clearance.

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.


The Correct Way to Install Piston Rings -

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

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

Installation of rings on the piston are as follows:

  1. The oil lubricating (bottom) ring(s) goes on first.
  2. The oil scraper (middle) ring goes on second.
  3. Then the compression (top) ring goes on last.

Never attempt to install piston rings in reverse order or they might break upon installation! Install the rings in the order as follows: (The below Ê applies to all 4-stroke small air- or water-cooled engines, automotive, tractor, heavy equipment engines, etc.)

  1. The bottom ring(s) usually have no particular (upward or downward) way of installing, as they don't flex either way. If it's a three-piece ring, the expander installs first and butts end to end. The ends do not over-lap. The expander "expands" the two thin oil lubricator rings so they can apply more pressure against the cylinder wall to work better.
  2. Make sure the middle or second 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 second 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, and if the engine smokes a lot, this ring can be removed and reinstalled right side up. It can be reused because very little wear has occurred to it. There is no need to purchase another new set of rings due to improper installation. Because installing new rings incorrectly doesn't necessarily cause them to wear more, they just cause the engine to smoke out the exhaust.
    • If there's no specific instructions on how to install the middle ring, and if a powerful magnifying glass isn't available to see the angle on the outer edge, then lightly rub the outer edge of the ring side to side against a flat piece of ceramic tile at an exact 90° angle. You should see a shiny area on one side of the angle. Mark the ring so the shiny area will face downward when installing the ring on the piston.
  3. And as for the top ring, if it has square edges with no bevel, then there's no certain way how it installs on the piston, being it just holds the compression. And just like the second ring, if there's a dot (punch mark) or the word TOP laser-etched on the ring, it faces upward.

Instructions on how to install the rings should be in the box they came in. 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.

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 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.

The Differences Between "Deglazing", "Honing" and "Boring" a Cylinder:

Deglazing the Cylinder -

Despite how nice and smooth the cylinder wall may be, it'll always a good idea to "break the glaze" with a drill-operated, spring-loaded cylinder deglazer. Apply a lightweight lubricant such as Liquid Wrench or WD-40, and when deglazing the cylinder, and on the last few strokes, give it a quick up and down motion to produce a 60° cross hatch pattern. This only takes a few seconds to complete. The grooves in the crosshatch marks retains oil so the rings can break-in quicker and last longer. After the deglazing process, thoroughly clean the cylinder wall with cleaning solvent, then finish cleaning with warm soap and water to remove the tiny metal fragments left behind during the deglazing or honing process. If these are not removed, severe wear of the rings could result. Then use a clean cloth (white in color) around the cylinder wall to see that the wall is free of the metal fragments. Remember - metal flake looks in paint, not in crankcase oil.

About Piston Ring Gaps -

IMPORTANT! As an engine heats up while running, due to normal combustion heat and cylinder wall friction, the piston rings expand, decreasing 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 4,000 rpms) and the wider gap specs are for high-performance engines (wide open throttle) because they operate at a much higher temperature. Not all piston rings are machined perfect. Fit each ring squarely in the cylinder with the piston and use a feeler gauge to accurately measure the gap. Grind or file the ends of each ring until the gap is within specs. Failure to do this could cause the ends of the ring(s) will make contact, and the excessive expansion will cause the cylinder wall to become scuffed or scored.

Being piston rings rotate in the cylinder as the engine heats up and cools down, there is really no need to stagger the ring gaps 120° or 180° on the piston upon installation in the cylinder. Actually, it doesn't matter if the ring 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 rebuild an engine, I always prefer to stagger the ring gaps 180° just because it makes me feel good knowing they're offset. But then a few years later when I freshen the same engine (install new rings, etc.), I notice that the ring gaps are almost aligned with each other. It's weird how this happens, heat expansion does it. But if it'll make you feel better, go ahead and stagger the 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 with the same oil). Synthetic motor oil shouldn't be used on the piston rings or as a break-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. And 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 things, but not for assembly of a rebuilt engine. And on a cast iron block Kohler engine, ALWAYS apply oil inside the camshaft and on the cam pin to prevent engine seizure upon startup! If a freshly rebuilt engine is going to be in storage for a long period of time, quality automotive lubricating grease should be used instead of oil for the camshaft and pin, and on the rod/crank journal. The reason grease works better for storage is because most of the oil will eventually drain off the parts, allowing somewhat of a "dry startup", which could damage or cause excessive wear of valuable parts.

Piston Ring CompressorWhen installing the piston and rings in the cylinder, the 10hp, 12hp and 14hp 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 16hp flathead and 18hp OHV single cylinder cast iron block 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 stagger the ring end gaps 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!

Use a heavy wooden dowell 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.

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.

Advertisement:
If you need a new ring set or a new piston/rings assembly, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
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.
Ring sets for Kohler models K90 (3.6hp), K91 (4hp) cast iron block flathead engine with a STD size cylinder bore of 2.375" (2-3/8"). Made of high grade cast iron for durability.
  • Aftermarket -
    • STD size. Replaces Kohler part # 220801-S. Also replaces Briggs and Stratton part #'s 294232 and 295657 (3hp) and Clinton part # 233112500, 233122500. $15.00 per set, plus shipping & handling.
    • .010, .020" and .030" oversizes not available in aftermarket.
  • OEM Kohler -
    • STD size. OEM Kohler part # 220801-S. $45.00 per set, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 220802-S. $57.50 per set, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 220803-S. $67.00 per set, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 220804-S. $73.50 per set, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler models K90 (3.6hp), K91 (4hp) cast iron block flathead engine with a STD size cylinder bore of 2.375" (2-3/8"). Ring sets made of high grade cast iron for durability. FYI: The biggest piston and rings set available for any Kohler engine is .030". If a .030" cylinder wall is in bad condition, then the cylinder will need to be sleeved back for a STD size piston and rings, or acquire another block (matching yours) with a cylinder wall in good condition.

  • OEM Kohler. No longer available in aftermarket.
    • STD size. OEM Kohler part # 46 874 01-S. $164.00 per set, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 46 874 02-S. $192.00 per set, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 46 874 03-S. $192.00 per set, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 46 874 04-S. $192.00 per set, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 46 874 05-S. $192.00 per set, plus shipping & handling.
Ring sets for Kohler and Magnum models K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp) cast iron block flathead engines with a STD size cylinder bore of 2.9375" (2-15/16"). Made of high grade cast iron for durability. NOTE: The cylinder in model K141 will need to be bored to 2.9375" because the piston/rings for the 2-7/8" bore are no longer available.
  • Aftermarket. Rings listed below Ê fits the "old style" cast K-series piston. (Wide wrist pin spacing.)
    • STD size and .003" oversize. Replaces Kohler part # 232575-S. $15.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 232576-S. $10.00 each, plus shipping & handling.
    • .020" and .030" oversizes not available in aftermarket.
  • OEM Kohler. Rings listed below Ê fits the "old style" cast K-series piston. (Wide wrist pin spacing.)
    • STD size and .003" oversize. OEM Kohler part # 232575-S. $57.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 232576-S. $51.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 232577-S. $75.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 232578-S. $75.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Rings listed below Ê fits the "new style" forged Mahle piston. (Narrow wrist pin spacing.) Mahle piston and rings not available in aftermarket.
    • STD size and .003" oversize. OEM Kohler part # 41 108 01-S. $55.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 41 108 02-S. $59.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 41 108 03-S. $59.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 41 108 04-S. $59.00 each, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler and Magnum models K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp) cast iron block flathead engines with a STD size cylinder bore of 2.9375" (3-15/16"). Ring sets made of high grade cast iron for durability. NOTE: The cylinder in model K141 will need to be bored to 2.9375" because the piston/rings for the 2-7/8" bore are no longer available. FYI: The biggest piston and rings set available for any Kohler engine is .030". If a .030" cylinder wall is in bad condition, then the cylinder will need to be sleeved back for a STD size piston and rings, or acquire another block (matching yours) with a cylinder wall in good condition.

  • Aftermarket. Pistons and rings listed below Ê are the "old style" cast K-series design. (Wide wrist pin spacing.)
    • STD size. Replaces Kohler part # 41 874 05-S. $35.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 41 874 07-S. $30.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 41 874 08-S. $30.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 41 874 09-S. $37.00 each, plus shipping & handling.
  • OEM Kohler. Pistons and rings listed below Ê are the "old style" cast K-series design. (Wide wrist pin spacing.)
    • STD size. OEM Kohler part # 41 874 05-S. $171.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 41 874 06-S. $182.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 41 874 07-S. $171.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 41 874 08-S. $182.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 41 874 09-S. $178.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Pistons and rings listed below Ê are the "new style" forged Mahle design. (Narrow wrist pin spacing.) Mahle piston and rings not available in aftermarket.
    • STD size. OEM Kohler part # 41 874 10-S. $141.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 41 874 11-S. $136.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 41 874 12-S. $136.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 41 874 13-S. $175.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 41 874 14-S. $136.00 each, plus shipping & handling.
Ring sets for Kohler K-series and Magnum models K241/M10 (10hp) and K482 (18hp) cast iron block flathead engines with a STD size cylinder bore of 3.250" (3-1/4"). Ring sets made of high grade cast iron for durability. Note - These ring sets will not fit high-performance aftermarket pistons (Arias, JE, etc.). Check your piston carefully before ordering.
  • Aftermarket. Ring Sets. Priced per cylinder.
    • STD size. Replaces Kohler part # 235287-S. $22.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 235288-S. $14.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 235289-S. $13.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 235290-S. $13.00 each, plus shipping & handling.
  • OEM Kohler. Ring Sets. Priced per cylinder.
    • STD size and .003" oversize. OEM Kohler part # 235287-S. $72.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 235288-S. $78.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 235289-S. $78.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 235290-S. $78.00 each, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler K-series and Magnum models K241/M10 (10hp) and K482 (18hp) cast iron block flathead engines with a STD size cylinder bore of 3.250" (3-1/4"). Compression height is 1.63". And being the wrist pin is centered, these pistons can be installed in either direction. Ring sets made of high grade cast iron for durability.

  • Aftermarket. Piston and Ring Sets.
    • STD size. Replaces Kohler part # 47 874 01-S. $48.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 47 874 03-S. $36.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 47 874 04-S. $36.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 47 874 05-S. $42.00 each, plus shipping & handling.
  • OEM Kohler. Piston and Ring Sets.
    • STD size. OEM Kohler part # 47 874 01-S. $204.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 47 874 02-S. $221.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 874 03-S. $204.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 874 04-S. $204.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 874 05-S. $204.00 each, plus shipping & handling.
Ring sets for Kohler K-series and Magnum models K301/M12 (12hp) and K532 (20hp) cast iron block flathead engines with a STD size cylinder bore of 3.375" (3-3/8"). Made of high grade cast iron for durability. Note - These ring sets will not fit high-performance aftermarket pistons (Arias, JE, etc.). Check your piston carefully before ordering.
  • Aftermarket. Rings listed below Ê fits the "old style" cast K-series piston. Priced per cylinder.
    • STD size. Replaces Kohler part # 48 108 01-S. $15.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 48 108 02-S. $16.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 48 108 03-S. $17.55 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 48 108 04-S. $16.00 each, plus shipping & handling.
  • OEM Kohler. Rings listed below Ê fits the "old style" cast K-series piston. Priced per cylinder.
    • STD size and .003" oversize. OEM Kohler part # 48 108 01-S. $72.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 48 108 02-S. $98.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 48 108 03-S. $98.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 48 108 04-S. $98.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Rings listed below Ê fits the "new style" (Magnum) forged Mahle piston. Priced per cylinder. Mahle piston and rings not available in aftermarket.
    • STD size and .003" oversize. OEM Kohler part # 47 108 01-S. $68.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 108 01-S. $85.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 108 03-S. $68.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 108 04-S. $68.00 each, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler K-series and Magnum models K301/M12 (12hp) cast iron block flathead engines with a STD size cylinder bore of 3.375" (3-3/8"). Compression height is 1.7". And being the wrist pin is centered, these pistons can be installed in either direction. Ring sets made of high grade cast iron for durability. To maintain engine balance in a twin cylinder engine, two sets of matching oversize pistons and rings are required. FYI: The biggest piston and rings set available for any Kohler engine is .030". If a .030" cylinder wall is in bad condition, then the cylinder will need to be sleeved back for a STD size piston and rings, or acquire another block (matching yours) with a cylinder wall in good condition.

  • Aftermarket. Pistons and rings listed below Ê are the "old style" cast K-series design. (Wide wrist pin spacing.) Priced per cylinder.
    • STD size. Replaces Kohler part #'s 47 874 06-S, 48 874 01-S. $34.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part #'s 47 874 08-S, 48 874 03-S. $48.50 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part #'s 47 874 09-S, 48 874 04-S. $45.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 47 874 10-S. $51.00 each, plus shipping & handling.
  • OEM Kohler. Pistons and rings listed below Ê are the "old style" cast K-series design. (Wide wrist pin spacing.) Priced per cylinder.
    • STD size. OEM Kohler part # 47 874 06-S. $152.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 47 874 07-S. $166.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 874 08-S. $204.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 874 09-S. $204.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 874 10-S. $204.00 each, plus shipping & handling.
    • STD size. OEM Kohler part # 48 874 01-S. $199.60 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 48 874 03-S. $199.60 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 48 874 04-S. $199.60 each, plus shipping & handling.
  • OEM Mahle/Kohler. Pistons and rings listed below Ê are the "new style" forged Mahle (12hp Magnum) design, but will also fit the K532 engine. Priced per cylinder. (Narrow wrist pin spacing.) Mahle piston and rings not available in aftermarket.
    • STD size. OEM Kohler part # 47 874 16-S. $142.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 47 874 17-S. $150.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 874 18-S. $150.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 874 19-S. $150.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 874 20-S. $150.00 each, plus shipping & handling.
Ring sets for Kohler K-series and Magnum models K321/M14 (14hp) and K582 (23hp) cast iron block flathead engines with a STD size cylinder bore of 3.500" (3-1/2"). Made of high grade cast iron for durability. Note - These ring sets will not fit high-performance aftermarket pistons (Arias, JE, etc.). Check your piston carefully before ordering.
  • Aftermarket. Rings listed below Ê fits the "old style" cast K-series piston.
    • STD size. Replaces Kohler part # 48 108 05-S. $22.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 48 108 06-S. $11.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 48 108 07-S. $14.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 48 108 08-S. $14.00 each, plus shipping & handling.
  • OEM Kohler. Rings listed below Ê fits the "old style" cast K-series piston.
    • STD size and .003" oversize. OEM Kohler part # 48 108 05-S. $83.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 48 108 06-S. $76.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 48 108 07-S. $98.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 48 108 08-S. $98.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Rings listed below Ê fits the "new style" forged Mahle piston. Mahle piston and rings not available in aftermarket.
    • STD size and .003" oversize. OEM Kohler part # 47 108 05-S. $92.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 108 06-S. $87.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 108 07-S. $87.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 108 08-S. $87.00 each, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler K-series and Magnum models K321/M14 (14hp) and K582 (23hp) cast iron block flathead engines with a STD size cylinder bore of 3.500" (3-1/2"). Compression height is 1.7". And being the wrist pin is centered, these pistons can be installed in either direction. Ring sets made of high grade cast iron for durability. FYI: The biggest piston and rings set available for any Kohler engine is .030". If a .030" cylinder wall is in bad condition, then the cylinder will need to be sleeved back for a STD size piston and rings, or acquire another block (matching yours) with a cylinder wall in good condition.

  • Aftermarket. Pistons and rings listed below Ê are the "old style" cast K-series design. (Wide wrist pin spacing.)
    • STD size. Replaces Kohler part # 47 874 11-S. $60.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 47 874 13-S. $53.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 47 874 14-S. $45.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 47 874 15-S. $44.00 each, plus shipping & handling.
  • OEM Kohler. Pistons and rings listed below Ê are the "old style" cast K-series design. (Wide wrist pin spacing.)
    • STD size and .003" oversize. OEM Kohler part # 47 874 11-S. $204.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 47 874 12-S. $172.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 874 13-S. $153.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 874 14-S. $153.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 874 15-S. $204.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Pistons and rings listed below Ê are the "new style" forged Mahle design. (Narrow wrist pin spacing.) Mahle piston and rings not available in aftermarket.
    • STD size. OEM Kohler part # 47 874 16-S. $142.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 47 874 17-S. $150.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 47 874 18-S. $150.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 47 874 19-S. $150.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 47 874 20-S. $150.00 each, plus shipping & handling.
Ring sets for Kohler K-series and Magnum models K341/M16 (16hp; flathead) and K361 (18hp single cylinder OHV) cast iron block engines with a STD size cylinder bore of 3.750" (3-3/4"). Ring sets made of high grade cast iron for durability. Note - These ring sets will not fit high-performance aftermarket pistons (Arias, JE, etc.). Check your piston carefully before ordering.
  • Aftermarket. Ring set listed below Ê fits the "old style" cast K-series piston.
    • STD size. Replaces Kohler part # 45 108 06-S. $26.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 45 108 07-S. $62.00 each, plus shipping & handling.
    • .020" and .030" oversize ring sets not available in aftermarket.
  • OEM Kohler. Rings listed below Ê fits the "old style" cast K-series piston.
    • STD size and .003" oversize. OEM Kohler part # 45 108 06-S. $77.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 45 108 07-S. $81.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 45 108 08-S. $81.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 45 108 09-S. $81.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Rings listed below Ê fits the "new style" forged Mahle piston. Mahle piston and rings not available in aftermarket.
    • STD size and .003" oversize. OEM Kohler part # 41 108 01-S. $145.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 41 108 02-S. $135.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 41 108 03-S. $88.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 41 108 04-S. $88.00 each, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler K-series and Magnum models K341/M16 (16hp; flathead) and K361 (18hp single cylinder OHV) cast iron block engines with a STD size cylinder bore of 3.750" (3-3/4"). Compression height is 1.7". Wrist pin is offset to reduce piston slap. Therefore, piston installs with notch facing flywheel. Ring sets made of high grade cast iron for durability. FYI: The biggest piston and rings set available for any Kohler engine is .030". If a .030" cylinder wall is in bad condition, then the cylinder will need to be sleeved back for a STD size piston and rings, or acquire another block (matching yours) with a cylinder wall in good condition.

  • Aftermarket. Pistons and rings listed below Ê are the "old style" cast K-series design. (Narrow wrist pin spacing.)
    • STD size. Replaces Kohler part # 45 874 01-S. $100.00 each, plus shipping & handling.
    • .010" oversize. Replaces Kohler part # 45 874 03-S. $104.00 each, plus shipping & handling.
    • .020" oversize. Replaces Kohler part # 45 874 04-S. $104.00 each, plus shipping & handling.
    • .030" oversize. Replaces Kohler part # 45 874 05-S. $104.00 each, plus shipping & handling.
  • OEM Kohler. Pistons and rings listed below Ê are the "old style" cast K-series design. (Narrow wrist pin spacing.)
    • STD size and .003" oversize. OEM Kohler part # 45 874 01-S. $239.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 45 874 02-S. $254.75 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 45 874 03-S. $239.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 45 874 04-S. $233.60 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 45 874 05-S. $190.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Pistons and rings listed below Ê are the "new style" forged Mahle design. (Narrow wrist pin spacing.) Mahle piston and rings not available in aftermarket.
    • STD size and .003" oversize. OEM Kohler part # 45 874 11-S. $270.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 45 874 12-S. $220.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 45 874 13-S. $261.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 45 874 14-S. $261.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 45 874 15-S. $203.00 each, plus shipping & handling.
Ring Sets for Kohler models MV16, KT17, KT17II, KT19, KT19II, M18, MV18, M20 and MV20 flathead twin cylinder engines with a STD size cylinder bore of 3.125" (3-1/8"). The Magnum (M-series) engines have the new style forged Mahle pistons and rings. The Mahle rings will also fit the old style KT-series cast pistons. Ring sets for model KT21 are no longer available.
  • Aftermarket. Ring sets. Priced per cylinder. Order two sets for one engine.
    • STD size. Replaces Kohler part # 52 108 09-S. $36.00 per set, plus shipping & handling.
    • .010", .020" and .030" oversizes not available in aftermarket.
  • OEM Mahle/Kohler. Ring sets. Priced per cylinder. Order two sets for one engine.
    • STD size and .003" oversize. OEM Kohler part # 52 108 09-S. $67.00 per set, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 52 108 10-S. $77.00 per set, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 52 108 11-S. $74.00 per set, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 52 108 12-S. $86.00 per set, plus shipping & handling.

Piston, ring set, wrist pin and retaining clips for Kohler models MV16, KT17, KT17II, KT19II, M18, MV18, M20 and MV20 flathead twin cylinder engines with a STD size cylinder bore of 3.125" (3-1/8"). The Magnum engines have the new style forged Mahle pistons and rings. Although the Mahle rings will fit the old style KT-series cast pistons, the Magnum pistons are not available for these engines. Pistons for model KT21 are no longer available. FYI: The biggest piston and rings set available for any Kohler engine is .030". If a .030" cylinder wall is in bad condition, then the cylinder will need to be sleeved back for a STD size piston and rings, or acquire another block (matching yours) with a cylinder wall in good condition.

  • OEM Kohler. Piston, Pin, Clips and Ring Sets for models KT17, KT17II. Wrist pin diameter: .6247"/.6249". Compression height: 1.125". Priced per cylinder. Order two sets for one engine. To maintain engine balance, two sets of matching oversize pistons and rings are required.
    • STD size and .003" oversize. OEM Kohler part # 52 874 01-S. $224.10 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 52 874 03-S. $224.30 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 52 874 04-S. $217.50 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 52 874 05-S. $217.70 each, plus shipping & handling.
  • OEM Mahle/Kohler. Piston, Pin, Clips and Ring Sets for models MV16, M18, MV18. Wrist pin diameter: .6247"/.6249". Compression height: 1.125". Priced per cylinder. Order two sets for one engine. To maintain engine balance, two sets of matching oversize pistons and rings are required. Mahle piston and rings not available in aftermarket.
    • STD size. OEM Kohler part # 52 874 11-S. $149.00 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 52 874 12-S. $143.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 52 874 13-S. $135.55 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 52 874 14-S. $143.00 each, plus shipping & handling.
    • .030" oversize no longer available. Use OEM Kohler part # 52 874 05-S instead. (KT17/KT17II pistons.) $217.70 each, plus shipping & handling.
  • OEM Kohler. Piston, Pin, Clips and Ring Sets for models KT19, KT19II. Wrist pin diameter: .7499"/.7501". Compression height: 1.1875". Priced per cylinder. Order two sets for one engine. To maintain engine balance, two sets of matching oversize pistons and rings are required.
    • STD size and .003" oversize. OEM Kohler part # 52 874 06-S. $170.70 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 52 874 08-S. $227.60 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 52 874 09-S. $227.60 each, plus shipping & handling.
    • .030" oversize no longer available. Use OEM Kohler part # 52 874 20-S instead. (M20, MV20 pistons.) $143.00 each, plus shipping & handling.
  • OEM Mahle/Kohler. Piston, Pin, Clips and Ring Sets for models M20, MV20. Wrist pin diameter: .7499"/.7501". Compression height: 1.1875". Priced per cylinder. Order two sets for one engine. To maintain engine balance, two sets of matching oversize pistons and rings are required. Mahle piston and rings not available in aftermarket.
    • STD size. OEM Kohler part # 52 874 16-S. $147.20 each, plus shipping & handling.
    • .003" oversize. OEM Kohler part # 52 874 17-S. $143.00 each, plus shipping & handling.
    • .010" oversize. OEM Kohler part # 52 874 18-S. $143.00 each, plus shipping & handling.
    • .020" oversize. OEM Kohler part # 52 874 19-S. $143.00 each, plus shipping & handling.
    • .030" oversize. OEM Kohler part # 52 874 20-S. $143.00 each, plus shipping & handling.
NOTE: High-quality ring sets, pistons and piston/rings assemblies are also available for other makes & models of small gas engines. And the piston assemblies that we sell will work with a stock connecting rod and crankshaft without the need for rebalancing. And always match a billet connecting rod of a certain length to an aftermarket piston (Arias, JE, etc.) that has the correct compression height. These two parts must be matched for the piston to come flush with the top of the engine block, or have a few thousands of an inch pop-out. If using a Kohler connecting rod, the compression height may not be correct with an aftermarket piston (Arias, JE, etc.) that has the wrong wrist pin offset. The same is true with a Kohler piston and a billet connecting rod of a the wrong length. You can find piston ring compressors on eBay.
NOTE: Complete engine rebuild kits are available, but a kit will cost more than if the parts were ordered individually. So please contact me with a list of parts you need, and I'll get back to you with a total including shipping & handling. And if you need a part or parts that's not listed here or for other make and model of engines, please contact me and I'll see if I can get it at a reasonable price.


"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:

  1. 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."

  2. 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.

  3. If the engine is ran continually at high rpm, 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.

Most 10hp (K241) pistons, and some other Kohler engines, don't come flush with the top of the engine block at TDC. Therefore, if installing bearing inserts and you want the piston to pop out of the cylinder a few thousands of an inch, the piston must first be placed in the cylinder without rings with a crankshaft journal at TDC, and then the piston height accurately measured. If you choose to pop the piston out of the cylinder, you must take into consideration the piston height and how far you want the piston to pop out of the cylinder. Example: If the piston comes within .020" of the top of the block and you want the piston to pop out at .020", then the big end of the rod must be offset-bored at .040". By the way - most competition pulling engines have the piston pop out of the cylinder.

The OEM head gasket has a compressed thickness of about .050". The piston and cylinder head needs to have a safety margin (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 safety margin 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 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: Removing metal from the edge of the piston for improved combustion

  1. Place the crankshaft in the block along with the bearing plate.
  2. With the rings off the piston, slide the piston, connecting rod with the bearing into the cylinder.
  3. Rotate the crankshaft so the piston is at the TDC position.
  4. Use a felt marker to place a line on the side of the piston next to the deck which face the valves.
  5. Remove the piston, and use a disc or belt 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.
  6. 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 assemblies 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 (10hp) and K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) flatheads and K361 (18hp OHV) Kohler OEM pistons, rods and crankshafts:

What does "Compression Height" of a Piston Mean?

Piston explaining the compression heightThe compression height is the measured distance from the top of the piston to the center of the wrist pin. The stock 10hp 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.

High-performance pistonMany 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 -

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 10hp is 2.875"; 12hp, 14hp and 16hp is 3.25")
Enter Rod Length: (From centerline of wrist pin hole to centerline of rod bearing hole. OEM Kohler 10hp is 5.558"; 12hp, 14hp and 16hp is 5.3")
Enter Piston Compression Height: (Distance from centerline of wrist pin to top of piston. OEM Kohler 10hp is 1.62"; 12hp, 14hp and 16hp is 1.7")
Answer: = Deck Clearance or Piston Height: (Distance from top of piston to top of engine block with piston positioned at true TDC.) (0 meaning flush w/deck; -0.xx means amount of piston pop-out.)


Why Having Proper Crankshaft End Play or End 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 can have an effect on the crankshaft main radial ball bearings and engine performance.

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

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

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, and the faster the crankshaft spins, the balls in the main radial ball bearings will spin just as fast, and despite having quality lubricating 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. When this happens, they swell a few thousands of an inch. If they swell too much, crankshaft end play 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 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. Just like the factory-built Chevy V8 engines, Kohler engineers knew what they were doing when they designed the internal parts for their engines.

A much lower cost alternative to using a machined aftermarket billet aluminum bearing plate for a pulling engine is to make one from OEM that's used on an older 10-14hp Kohler engine with the smaller 8" flywheel and starter/generator. Use a vertical metal bandsaw to cut the outer portion off (use safety glasses and extreme caution!), then smooth any sharp edges. A bearing plate made from OEM for a pulling engine may not look the best, but because of the reinforced raised ribbing, it's just as strong to maintain proper crankshaft end-play clearance. And besides, once the engine is installed in the tractor, being the cut-out bearing plate is behind the flywheel and under the safety shielding, no one will ever see it!

The gaskets on the bearing plate of a Kohler engine are also shims to adjust the crankshaft end play. Add or subtract gaskets until the proper clearance for crankshaft end play is obtained. Use a feeler gauge between the crankshaft and one of the main radial ball bearings or a dial indicator on the end of the crankshaft to check the end play clearance. 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 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 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 higher rpms with the little more clearance.

Sometimes when a Kohler engine is reassembled, it will take several gaskets to achieve the proper crankshaft end play. And as long as the bearing on the PTO end is fully seated and the crankshaft is more or less butted against the bearing, the [OEM cast] cam timing will be in perfect alignment.


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

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. If they were all machined exactly the same under controlled conditions, such as with CNC machines, the parts would all measure exactly the same and no shimming would be required. Either that, or the parts were machined on an early Monday morning, or late Friday afternoon.

Back in the day when Kohler machined their cast iron engine blocks, camshafts and crankshafts, quality control wasn't as strict as it is today with the precision of CNC machines. The same is true with the Cub Cadet cast iron case transaxles, shafts and gears. That's why the camshaft and crankshaft require shimming (steel shims or various thicknesses of gaskets) to set the end-play clearances of either. And 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).

Anyway, to adjust the crankshaft end play, set it according to Kohler's specs. Use a heavy wooden or leather mallet to bump the crank back and forth so you can get a feeler gauge between the PTO bearing and crank to measure the end play clearance. And despite if the main radial ball bearings fit tight on the crank, as long as the end play is set right, the engine should run fine.

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 at around 72° F.


If all the oil were cleaned from the Kohler crankshaft main [ball] bearings with cleaning solvent and allowed to thoroughly dry, and then if the bearings were spun by hand, and if the bearings isn't worn much or at all, they will make a rattling sound. The noise isn't necessarily because the bearing is worn, the noise is caused by the balls running dry on the races (metal to metal contact) because there's no oil to separate the two. Apply a small amount of motor oil to the balls/races and then spin the bearings by hand. They should be a lot quieter now. The same thing will happen with new bearings. And if the bearings have very little free play in them (about .005"), like they're worn, don't worry about this. As the engine rpms 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 forged Mahle 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 cast K-series 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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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.
NOS (New Old Stock) connecting rods for Kohler K-series K90 (3.6hp), K91 (4hp) engine. These rods are from dealer's old stock and no longer available from Kohler or any other source. NOTE: The .010" undersize rod have a small hole drilled through the beam section indicating it's .010" undersize. Crank journal must be reground .010" undersize to match this rod.
  • OEM Kohler -
    • STD size. OEM Kohler part # B-220111-S. (Numbers 220489 embossed on rod.) $57.00 each, plus shipping & handling. (When available.)
    • .010" undersize. OEM Kohler part # B-220111-10-S. $69.00 each, plus shipping & handling. (When available.)
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal.
New connecting rods for Kohler K-series models K141 (6¼hp), K160 (6.6hp) and K161 (7hp) cast iron block flathead engines. These are plain aluminum bearing surface rods. Bearing inserts are not available for these particular rods. NOTE: The .010" undersize rods have a small hole drilled through the beam section indicating that it's .010" undersize. Crank journal must be reground .010" undersize to match this rod.
  • Aftermarket -
    • STD size. Replaces Kohler part # B-230039-S. $45.00 each, plus shipping & handling.
    • .010" undersize. Replaces Kohler part # B-230039-10-S. $45.00 each, plus shipping & handling
  • OEM Kohler -
    • STD size. OEM Kohler part # B-230039-S. $93.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # B-230039-10-S. $70.00 each, plus shipping & handling.
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal.
New connecting rod for Kohler K-series and Magnum models K181/M8 (8hp) cast iron block flathead engines. These are plain aluminum bearing surface rods. Bearing inserts are not available for these particular rods. NOTE: The .010" undersize rods have a small hole drilled through the beam section indicating that it's .010" undersize. Crank journal must be reground .010" undersize to match this rod.
  • Aftermarket. For the "old style" cast K-series piston. (Strong rods.) (Wide wrist pin hole.)
    • STD size. Replaces Kohler part # 41 067 10-S. $30.00 each, plus shipping & handling.
    • .010" undersize. Replaces Kohler part # 41 067 11-S. $45.00 each, plus shipping & handling.
  • OEM Kohler. For the "old style" cast K-series piston. (Wide wrist pin hole.)
    • STD size. OEM Kohler part # 41 067 10-S. $62.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 41 067 11-S. $80.00 each, plus shipping & handling.
  • OEM Kohler. For the "new style" forged Mahle piston. (Narrow wrist pin hole.)
    • STD size. OEM Kohler part # 41 067 08-S. $80.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 41 067 09-S. $80.00 each, plus shipping & handling.
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal.
New connecting rod for Kohler K-series and Magnum models K241/M10 (10hp) cast iron block flathead engines. Strong rods. Comes with long dipper. These are plain aluminum bearing surface rods, but I can bore rod and install bearing inserts if you wish. 5.558" length. NOTE: 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. The .010" undersize rod have a small hole drilled through the beam section indicating it's .010" undersize. Crank journal must be reground .010" or .020" undersize to match the rod.
  • Aftermarket -
    • STD size. Replaces Kohler part # 47 067 13-S. $31.00 each, plus shipping & handling.
    • .010" undersize. Replaces Kohler part # 47 067 14-S. $31.00 each, plus shipping & handling.
    • .020" undersize. No Kohler part number. $48.00 each, plus shipping & handling.
  • OEM Kohler -
    • STD size. OEM Kohler part # 47 067 13-S. $75.30 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 47 067 14-S. $95.35 each, plus shipping & handling.
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal. Bearing inserts cannot be used.
New "one color" connecting rods for Kohler K-series and Magnum models K301/M12 (12hp) and K321/M14 (14hp) cast iron block flathead engines. Comes with long dipper. These are plain aluminum bearing surface rods, but I can bore rod and install bearing inserts if you wish. 5.3" length. NOTE: 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. The .010" undersize rod have a small hole drilled through the beam section indicating it's .010" undersize. Crank journal must be reground .010" or .020" undersize to match the rod.
  • Aftermarket. For the "old style" cast K-series piston. (Wide wrist pin hole.)
    • STD size. Replaces Kohler part # 47 067 09-S. $28.00 each, plus shipping & handling.
    • .010" undersize. Replaces Kohler part # 47 067 10-S. $36.00 each, plus shipping & handling.
    • .020" undersize. No Kohler part number. $48.00 each, plus shipping & handling.
    • .020" undersize. Wrist pin hole machined narrow for Mahle piston. $60.00 each, plus shipping & handling.
  • OEM Kohler. For the "old style" cast K-series piston. (Wide wrist pin hole.)
    • STD size. OEM Kohler part # 47 067 09-S. $58.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 47 067 10-S. $70.00 each, plus shipping & handling.
  • OEM Kohler. For the "new style" forged Mahle piston. (Narrow wrist pin hole.) These rods will also fit the K341 and K361 cast pistons. These rods have a thicker beam section which is suitable for wide open throttle operation (w/bearing inserts) when rotating assembly is precision spin-balanced.
    • STD size. OEM Kohler part # 45 067 24-S. $93.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 45 067 25-S. $129.00 each, plus shipping & handling.
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal. Bearing inserts cannot be used.
New "one color" connecting rods for Kohler K-series and Magnum K341/M16 (16hp) cast iron block flathead engines. These rods have a narrow wrist pin hole. Comes with long dipper. These are plain aluminum bearing surface rods, but I can bore rod and install bearing inserts if you wish. 5.3" length. NOTE: 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. The .010" under rod have a small hole drilled through the beam section indicating it's .010" undersize. Crank journal must be reground .010" undersize to match this rod.
  • Aftermarket. All 16hp rods, K-series or Magnum, have a narrow wrist pin hole.
    • STD size. Replaces Kohler part # 45 067 24-S. $32.00 each, plus shipping & handling.
    • .010" undersize. Replaces Kohler part # 45 067 25-S. $48.00 each, plus shipping & handling.
    • .020" undersize. Wrist pin hole machined narrow for K341/K361 piston. $68.00 each, plus shipping & handling.
  • OEM Kohler. All 16hp rods, K-series or Magnum, have a narrow wrist pin hole so it can have more space to move side to side if it needs to. If a wider rod is used, binding would occur, and the rod would wear more on the crank journal. These rods have a thicker beam section which is suitable for wide open throttle operation (w/bearing inserts) when rotating assembly is precision spin-balanced.
    • STD size. OEM Kohler part # 45 067 24-S. $93.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 45 067 25-S. $129.00 each, plus shipping & handling.
    • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal. Bearing inserts cannot be used.These rods have a thicker beam section which is suitable for wide open throttle operation (w/bearing inserts) when rotating assembly is precision spin-balanced.
Used and in excellent condition - ALCOA connecting rods for Kohler K-series K361 (18hp OHV) engine. Also fits the K301/M12 (12hp), K321/M14 (14hp) and K341/M16 (16hp) engines. These rods are no longer available from Kohler. Extremely strong rod. These rods have a narrow wrist pin hole. Comes with long dipper. These are plain aluminum bearing surface rods, but I can bore rod and install bearing inserts if you wish. 5.3" length. NOTE: 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. The .010" undersize rod have a small hole drilled through the beam section indicating it's .010" undersize. Crank journal must be reground .010" undersize to match this rod.
  • OEM Kohler. All ALCOA K361 rods have a narrow wrist pin hole for the Mahle, K341 or K361 pistons.
    • STD size. OEM Kohler part # 45 067 15-S. $120.00 each, plus shipping & handling. (When available.)
    • .010" undersize. OEM Kohler part # 45 067 17-S. $120.00 each, plus shipping & handling. (When available.)
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal. Bearing inserts cannot be used.
New connecting rods for Kohler KT and Magnum models MV16, KT17, KT17II, M18, MV18 twin cylinder flathead engines with a crank journal diameter of 1.3733"/1.3738". NOTE: The .010" undersize rods have a small hole drilled through the beam section indicating that it's .010" undersize. Crank journal must be reground .010" undersize to match this rod. And new rods for models KT19, KT19II, KT21 are no longer available. Also, the KT17 cylinders are different than the M18 cylinders because the OEM KT17 rods are narrower than the M18 rods. To make the KT17 cylinders work with M18 rods, grind away (notch out) the lower portion of the cylinders until the rods clear. Or acquire a couple of M18 cylinders that's in good condition.
  • Aftermarket -
    • STD size. Replaces Kohler part # 52 067 67-S. $70.00 each, plus shipping & handling.
    • .010" undersize. Replaces Kohler part # 52 067 68-S. $90.00 each, plus shipping & handling.
  • OEM Kohler -
    • STD size. OEM Kohler part # 52 067 67-S. $89.00 each, plus shipping & handling.
    • .010" undersize. OEM Kohler part # 52 067 68-S. $111.30 each, plus shipping & handling.
  • NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal(s).
New connecting rods for Kohler KT and Magnum twin cylinder engine models M20, MV20 with a crank journal diameter of 1.4993"/1.4998". NOTE: The .010" undersize rods have a small hole drilled through the beam section indicating that it's .010" undersize. Crank journal must be reground .010" undersize to match this rod.
  • STD size rod no longer available.
  • .010" undersize. OEM Kohler part # 52 067 72-S. $83.65 each, plus shipping & handling.
  • Not available in aftermarket.

NOTE: The alternative to using an undersize rod - If a STD size or .010" undersize rod is in good condition, the matching crank journal can be reground so it's perfectly round again and then if the original rod(s) isn't badly scored or burnt, it can be resized to fit to odd-size undersize journal(s).

Crankshaft Main Bearings (Sleeve Flange Bushings) for Kohler KT and Magnum twin cylinder engine models MV16, KT17, KT17II, KT19, KT19II, KT21, M18 MV18, M20 and MV20. NOTE: Crankshaft main journal must be reground to .010" or .020" undersize to match the .010" or .020" undersize bearings. Also, on these engines, one main journal can be reground undersize if it's worn beyond specs, and the other can remain STD size if it's within specs. Not available in aftermarket.
  • STD size. OEM Kohler part # 52 030 10-S. $60.35 each, plus shipping & handling.
  • .010" undersize. OEM Kohler part # 52 030 11-S. $120.34 each, plus shipping & handling.
  • .020" undersize. OEM Kohler part # 52 030 12-S. $120.34 each, plus shipping & handling.
Connecting rods for Kohler engine models K482, K532, K582 or K660/K662 have been discontinued from Kohler. But they can be purchased off of eBay when they're available. I don't stock these rods either. And with the crank journals reground .010", .020" or .030" undersize, when the K532 or K582 connecting rods are bored for installation of bearing inserts, certain undersize bearing inserts for British MG car engines will fit the K532 and K582 rods perfectly. Contact Elson Nichols of Loop 70 Auto Parts & Automotive Machine Shop, 14 Bus. Loop 70 East, Columbia, Missouri 65201 USA. Phone: 1-573-449-0893. Email: vjnen@centurytel.net. He can bore these rods and install the MG bearing inserts for a reasonable price.
  • The OEM Kohler part numbers for the K482 connecting rods are: A-277130-S (STD size) and A-277130-S-10 (.010" undersize).
  • The OEM Kohler part numbers for the K532 or K582 connecting rods with [K301 or K321] cast pistons (wide wrist pin hole) are: 48 067 12-S (STD size) and 48 067 13-S (.010" undersize).
  • The OEM Kohler part numbers for the K532 and 582 connecting rods with [M12 or M14] Mahle pistons (narrow wrist pin hole.) are: 48 067 16-S (STD size) and 48 067 17-S (.010" undersize).
  • The OEM Kohler part numbers for the K660/K662 connecting rod is A-271741-S (aluminum rod); A-270890 (steel rod). Bearing inserts for these rods are no longer available from Kohler.
  • NOTE: The alternative to using undersize rods - If a STD size or an .010" undersize rod is in good condition, the matching crank journal can be reground until it's perfectly round again and then if the original rod isn't badly scored or burnt, it can be resized (in a connecting rod honing machine) to fit or match the odd-size undersize journal. Bearing inserts cannot be used in this procedure.
Crankshaft Main Bearings (Sleeve Flange Bushings) for Kohler twin cylinder engine models K482, K532 and K582. NOTE: Crankshaft main journal must be reground to .010" or .020" undersize to match the .010" or .020" undersize bearings. Also, on these engines, one main journal can be reground undersize if it's worn beyond specs, and the other can remain STD size if it's within specs. Not available in aftermarket.
  • STD size. OEM Kohler part # 48 030 06-S. $58.90 each, plus shipping & handling.
  • .010" undersize. OEM Kohler part # 48 030 07-S. $153.55 each, plus shipping & handling.
  • .020" undersize. OEM Kohler part # 48 030 05-S. $101.70 each, plus shipping & handling.
Camshaft Bushing (Bearing) for Kohler twin cylinder engine models K482, K532 and K582. Fits flywheel end.
  • OEM Kohler part # 48 158 03-S. $20.25 each, plus shipping & handling.

Bearing for the PTO end (part # 277039-S) is no longer available from Kohler and not available in aftermarket.

Bearing Inserts and Machine Work for Connecting Rods -
  • Federal Mogul FP9885CP bearing inserts available in STD size, .010", .020" and .030" undersizes. $15.00 per pair, plus shipping & handling.
  • Federal Mogul FP9885CPA bearing inserts available in STD size, .010", .020" and .030" undersizes. $15.00 per pair, plus shipping & handling.
  • Clevite 77 CB278 bearing inserts available in STD size, .010" and .020" undersizes only. $15.50 per pair, plus shipping & handling.
  • Clevite 77 CB279 bearing inserts available in STD size, .010" and .020" undersizes only. $17.50 per pair, plus shipping & handling.
  • Bore and notch Kohler 10hp-18hp cast iron block single cylinder and KT21, M20 and MV20 twin cylinder connecting rods for installation of bearing inserts. An innovative concept by Brian Miller, because nobody else advertise this service. $25.00 labor each, plus shipping & handling.
    • NOTE: If a crank journal is worn beyond specs or badly scored/burnt,it will need to be reground to match the appropriate size bearing inserts. And if you want me to bore a rod for you, please let me know if you want the bearing insert centered in the bore of the rod (piston flush with top of block) or offset .020" or more (up to .125" at no extra charge) 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 yard work, stock or high rpm pulling competition engines. The rod will need to be bored exactly 1.625" for proper bearing to journal oil clearance.
    • FYI - 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 between the bolts or studs. Whenever this happens, I grind away part of each bearing shell so they'll clear the rod bolt. I've talked to other machinist who bore Kohler rods about this and they tell me sometimes the same thing happens with them. But as long as the bearing shells are ground for clearance of the bolt, it poses no problems.
    • NOTE: On the K241/M10 (10hp) Kohler engines, the piston seems to come within .020"± from the top of the block, which lowers the compression ratio. Therefore, when boring the rod for installation of bearing inserts, it'll be a good idea to offset the bore .020" towards the oil dipper (lengthen the rod by .020") so the piston will be more or less flush with the top of the block. And offset the bore .040" for a .020"± piston pop-out.
    • 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 K301 (12hp) or K321 (14hp) old style connecting rod for use with K341 or K361 16hp/18hp cast piston or "new style" forged Mahle piston. $20.00 labor, plus return shipping & handling.

To identify this particular type of rod, they look a lot like Kohler's 12hp, 14hp 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 Kohler-made connecting rod to hold up to around 6,000 rpm in the 12, 14 and 16hp engines are the ones made for Kohler's 16hp flathead engines. They are of one color and the superseded part number for this rod is 45 067 24-S. This is for a standard size rod. The correct part number for a .010" undersize rod is 45 067 25-S. Most .010" undersize rods have a small hole drilled through the beam section. These rods have a thicker beam section which is suitable for wide open throttle operation (w/bearing inserts) when rotating assembly is precision spin-balanced.. 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 here for engine 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.

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 split lock washers of the appropriate 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 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 here to learn about precision engine balancing.


IMPORTANT! How Bearing Inserts Protect An Engine -

Due to lack of lubrication in the crankcase, and/or at very high rpm, an ordinary aluminum bearing surface connecting rod will most likely 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 bearings wear, they won't score the crank journal like an ordinary aluminum bearing surface rod will. In most cases, a rod with bearing inserts will knock, but rarely cause the rod to break. If the engine 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. Sometimes the bore in the rod can become oblong or "egg-shaped" after taking a pounding from a worn bearing. If this happens, it will need to be resized in a connecting rod honing machine to make the bore a perfect circle again. 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.

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 yard work or for stock tractor pulling (4,000 rpms). 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 impact or 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 rpms. You'll also have more confidence knowing your engine has bearing inserts. Return to previous paragraph. È

IMPORTANT! Upon installation of a connecting rod in a Kohler engine, the oil hole in the cap faces toward the camshaft! 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 oblong or "egg-shaped," which will bind on the crank journal. And DO NOT over-tighten the rod bolts or nuts! If the threads strip out in a rod, then perhaps a longer grade 8 fine thread bolt can be installed in reverse to serve as a stud (the rod will need to be machined for head bolt clearance) and use a grade 8 nut. If this cannot be done, then the rod is scrap metal.

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 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 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 impact that the rod places on the crankshaft journal at high rpm. And it's still a good idea to have an additional .001" of additional oil clearance, even if bearing inserts are used. Using bearing inserts also strengthens a [stock] rod by cushioning the severe impact the rod places on the crankshaft at very high rpm.

If an aluminum bearing surface 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.
  • Oil dipper broken off of rod cap.
  • Malfunctioning, worn oil pump or clogged oil filter.
  • Too high engine rpms.
  • Insufficient oil clearance between rod and crank journal according to manufacturer's specs.
  • Insufficient oil clearance between rod and crank journal 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. The bearing that's used in the rods are actually made for one particular model of Continental Engines, model 469 (4 cylinder). 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.

About Machining a Rod for Bearing Inserts -

FYI - 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 between the bolts or studs. Whenever this happens, I grind away part of each bearing shell so they'll clear the rod bolt. I've talked to other machinist who bore Kohler rods about this and they tell me sometimes the same thing happens with them. But as long as the bearing shells are ground for clearance of the bolt, it 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 Bearing Inserts -

For pulling applications, the oil clearance between the rod bearing and crank journal should be .0035" with ± .0005" for wear. This allows the .001" more clearance for rod swelling (when hot; only at high rpm). It'll be good to use this clearance for stock engines, too.

Bearing inserts provide a little more oil clearance to protect the crank journal. If checking the oil clearance with PlastiGage, and if it shows the clearance to be .0032"-.0035", 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.

When the 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 rpms), 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...

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 sanding disc slightly (with the cap torqued to the rod, of course) to insure 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 pulling competition 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 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!

Advertisement:
For quality bearing inserts and bearing installation service, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.

Bearing Inserts and Machine Work for Connecting Rods -

  • Federal Mogul FP9885CP bearing inserts available in STD size, .010", .020" and .030" undersizes. $15.00 per pair, plus shipping & handling.
  • Federal Mogul FP9885CPA bearing inserts available in STD size, .010", .020" and .030" undersizes. $15.00 per pair, plus shipping & handling.
  • Clevite 77 CB278 bearing inserts available in STD size, .010" and .020" undersizes only. $15.50 per pair, plus shipping & handling.
  • Clevite 77 CB279 bearing inserts available in STD size, .010" and .020" undersizes only. $17.50 per pair, plus shipping & handling.
  • Bore and notch Kohler 10hp-18hp cast iron block single cylinder and KT21, M20 and MV20 twin cylinder connecting rods for installation of bearing inserts. An innovative concept by Brian Miller, because nobody else advertise this service. $25.00 labor each, plus shipping & handling.
    • NOTE: If a crank journal is worn beyond specs or badly scored/burnt,it will need to be reground to match the appropriate size bearing inserts. And if you want me to bore a rod for you, please let me know if you want the bearing insert centered in the bore of the rod (piston flush with top of block) or offset .020" or more (up to .125" at no extra charge) 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 yard work, stock or high rpm pulling competition engines. And the rod needs to be bored exactly 1.625" for proper bearing to journal clearance.
    • FYI - 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 between the bolts or studs. Whenever this happens, I grind away part of each bearing shell so they'll clear the rod bolt. I've talked to other machinist who bore Kohler rods about this and they tell me sometimes the same thing happens with them. But as long as the bearing shells are ground for clearance of the bolt, it poses no problems.
    • NOTE: On the K241/M10 (10hp) Kohler engines, the piston seems to come within .020"± from the top of the block, which lowers the compression ratio. Therefore, when boring the rod for installation of bearing inserts, it'll be a good idea to offset the bore .020" towards the oil dipper (lengthen the rod by .020") so the piston will be more or less flush with the top of the block. And offset the bore .040" for a .020"± piston pop-out.
    • 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 K301 (12hp) or K321 (14hp) old style connecting rod for use with K341 or K361 16hp/18hp cast piston or "new style" forged Mahle piston. $20.00 labor, plus return shipping & handling.


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, 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 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.

NOTE - 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.

And if you've ever wondered about this: the bolts and studs in Kohler connecting rods can be reused over and over. They're very durable. Besides, nobody makes replacement bolts or studs for Kohler rods.

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


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

  1. Worn connecting rod and/or crankshaft rod journal. 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.
  2. Loose fitting piston in the cylinder. To check for a worn 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. If the piston has a lot of play, you'll hear a knock-knock sound.
  3. Too much crankshaft end-play. To check for this, grasp the PTO end of the crankshaft or flywheel with your hand and forcibly move the crankshaft back and forth. If there's too much end-play, you'll see it and hear it.
  4. Worn balance gear bearings. To check for worn balance gear bearings, first remove the oil pan, and then move the balance gears side to side by hand. They may not make any noise when moving them by hand, but if they're excessively loose, they will make noise with the engine running. These can be removed without removing the crankshaft or rod/piston. With them removed, the engine will not vibrate any more than before. A heavy duty, angled-shaped, expandable snap ring pliers is required to remove the snap rings that holds the balance gears in place. Be sure to remove the thrust washers and spacers (if present), too. Leave the stub shafts intact. They will not interfere with anything.
  5. A 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.
  6. A loose flywheel or worn Cub Cadet clutch disc will also cause a knocking or rattling sound.
  7. A loud tapping sound is mostly caused by a valve with excessive stem-to-lifter clearance. Sometimes 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 replaced with one from a known lifter with a tight adjuster, or the entire lifter will need to be replaced.
  8. 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: Should Silicone Sealant Be Used or Not?

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 fix a warped part, resurface it on a flat belt sander, sanding disc, or a large, flat file. By the way - I've always preferred to use Clear RTV Silicone Adhesive Sealant for two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen 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 allows 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 gaps and cause the engine to smoke and burn oil.

To fix this...

  1. Remove the engine and place it upside-down on a work bench.
  2. Remove the sump cover.
  3. Thoroughly clean the gasket material and all parts.
  4. Install a new oil seal in the sump cover. (The old one will probably leak from the sump being removed.)
  5. 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 two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen between the parts.
  6. Install a new sump cover gasket on the engine block.
  7. Lubricate the crankshaft main journal and camshaft stub journal with motor oil to prevent damage due to a "dry startup."
  8. Apply the silicone sealant on the sump cover also.
  9. 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.


What Type of Motor Oil Should Be Used? Top of page

Motor Oil Recommendation:

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 allows 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.

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 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.

Rule of thumb is: Detergent oils should be used only if the engine has an oil filter. Because the debris in the oil is suspended in detergent oils, which can be filtered, with non-detergent oil, the debris settles to the bottom of the oil pan. But if the oil changed on a regular basis, detergent oils can be used in a non-filtered oiling system. What was mentioned above È is what most manufacturers suggest to use [non-detergent oil] in their non-filtered small engines, which does make sense. And you know as well as I do that nothing lasts forever in this world. And despite what kind of oil is used, eventually all engines will wear out sooner or later.

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 (above 4,000 rpm), don't use multi-weight oils such as 10W30 or 10W40. They could cause excessive wear, resulting in damage to internal parts. I've used SAE 30 at times then SAE 50 in our two Super-Stock tractors and have had good results with both oils.

But if you don't mind spending a few extra bucks, the best type of oil to use in a pulling application to use is full synthetic 10W40 motor oil. Test data shows that you can get a 1 to 2 percent increase in horsepower using full synthetic oil. There's also a less chance of a 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, Clear RTV Silicone Adhesive Sealant, etc., it doesn't break down like natural-based products 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 two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen 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 an 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.

CAUTION! 20W50 oil is recommended in high performance or heavy duty application engines with an oil pump. Because sometimes when 20W50 oil is used in an engine with splash lubrication (no oil pump), as the rpms increase, the oil is thick enough so the dipper (on the connecting rod) will "cut a groove" through the oil instead of splash it up and thoroughly lubricate the internal moving parts. This could cause the engine to rattle or knock and possibly cause damage or excessive wear to the connecting rod on the crank journal and on the piston.

Synthetic oil is mainly used in high-revving and high-performance engines that operate at higher 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.

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. A race car mechanic once told me 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 and Walmart sells them for less money than other places.

FYI - Did you know that full synthetic oil will not burn when poured on an open fire pit? Some brands will smoke and some won't, but they won't burn like conventional petroleum oil will.

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 magnet at the bottom of the oil pan to attract steel or cast iron metal shavings for longer engine life. But make sure the oil dipper on the connecting rod doesn't make contact with the magnet!

Do Not Use "Oil Thickener" in a Kohler Engine! (A customer's experience that I like to share.)

I had a 14hp Kohler engine in my shop last summer (2013) that burned a lot of oil. The owner told me the engine was recently rebuilt by somebody else, but always smoked badly, so he filled the crankcase with "motor oil thickener". He said after a while 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 ran out like honey or molasses! Anyway, he had me 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 oil thickener and couldn't splash it around in the crankcase like 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 second ring on the piston upside-down.)

Break-In Oils and Procedure for Ordinary (Lawn & Garden) Engines -

For proper break-in of a new or freshly rebuilt engine, use conventional (petroleum-based) SAE 30 weight motor oil containing an anti-wear additive, such as ZDDP (Zinc dithiophosphate), which place 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. 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. Then drain the oil while it's hot, and 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. 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.

Break-In Oils and Procedure for Pulling Engines -

For proper break-in of a freshly built or rebuilt pulling engine, use conventional (petroleum-based) SAE 30 weight motor oil containing an anti-wear additive, such as ZDDP (Zinc dithiophosphate), which place 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. Run the engine normally (up to 4,000 rpm) for 4-5 pulls. Then drain the oil while it's hot, and either continue to use ordinary SAE 30 oil, or switch to a quality 10W40 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.

And Remember... (added paragraph below on 7/13/14)

Rather if it's for competition pulling or for general yard and garden use, any fresh-built engine needs to fully break-in. Rings break-in quickly. But the valve faces needs to wear into the seats to seal in the compression 100%. The harder material the valves are made of, the longer it takes for them to "seat." 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, but I noticed it produced a little more power after 1,000 or so miles. This is because the valve faces wore into the seats, forming a perfect seal. So just to let you know, a fresh-built engine will not produce full power the first few times it's ran.

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 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.

Oil Refill Quantities for Kohler Engines

K90/K91 K141, K160/K161, K181/M8 K241A, K301A, K321A, K341A K241/M10, K301/M12, K321/M14, K341/M16, K361 KT17, KT17II, KT19, KT19II, KT21, M18, M20 MV16, MV18, MV20
3/4 Quart 1-1/4 Quarts 1 Quart (narrow shallow/flat bottom pan)
1-1/2 Quarts (narrow deep sump pan)
2 Quarts (wide base oil pan) 3 Quarts w/filter 2 Quarts w/filter

Advertisement: (posted 3/3/13)
If you need a quality oil filter, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
Oil Filters for Kohler engine models CH11 - CH15, CV11 - CV22, MV16, KT17II, KT19II, M18, M20, MV18 and MV20, K482, K532 and K582. Kohler part #'s 277233-S, 52 050 02-S1; Briggs and Stratton part # 491056 (Vanguard). Has anti-drainback valve to minimize dry engine start. The advantage of using a larger capacity oil filter is so it will allow for less scheduled oil changes because the filter can hold more debris than an ordinary filter.
  • Purolator brand. Specifications: 3" o.d. x 3.25" height (general use). $7.00 each, plus shipping & handling.
  • Purolator brand. Specifications: 3" o.d. x 3.6" height; (extended use). $7.00 each, plus shipping & handling.
  • Kohler brand. Specifications: 3" o.d. x 3-7/16" height (general use.); 8-11 psi pressure relief; 29 microns. OEM Kohler part # 52 050 02-S1. $10.45 each, plus shipping & handling.
  • Kohler brand. Specifications: 3" o.d. x 5-3/16" height (extended use); 8-11 psi pressure relief; 28 microns. OEM Kohler part # 277233-S. $14.75 each, plus shipping & handling.


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...

  1. First drain the oil from the engine.
  2. Remove the hood/grille from the tractor (they're easy to remove), remove the muffler, PTO pulley, electric clutch, wiring and fuel line from the engine.
  3. Remove the engine from the equipment and place it on a sturdy work bench or table.
  4. 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.
  5. Now position the engine upside-down and remove the bolts that secure the oil sump to the crankcase.
  6. Remove the oil sump, and then the camshaft can be removed from the engine.
  7. When installing a new (or good used) cam, be sure to align the match marks on both the cam gear teeth and crankshaft gear teeth! The crankshaft may need to be rotated for the marks to align.
  8. Reassembly is opposite of disassembly.
  9. Install a new sump cover gasket and the sump cover on the crankcase, and torque the bolts to specs.
  10. With the piston at TDC on the compression stroke, adjust the valves to specs and install a new valve cover gasket.
  11. Apply Clear RTV Silicone Adhesive Sealant on the gasket mating areas to lessen the chance of an oil leak. By the way - I've always preferred to use Clear RTV Silicone Adhesive Sealant for two reasons: being it's an adhesive, it bonds parts together, forming a leak-proof seal; and being it's clear, it makes for a clean-looking repair job. It can't be seen between the parts.
  12. 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. I've found several dipsticks and/or dipstick tubes that's not calibrated to certain 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 at higher rpm. Also, make sure that the "end cap" or "stop cap" is properly positioned on the dipstick. If it slipped out of position from normal wear, this will give an incorrect oil level reading, which the oil level will actually be too low. If it did slip, the cap will need to be realigned (calibrated) and tack-welded back in place.

To fix a loose fitting oil dipstick tube, remove the tube, and use something tapered or a flared socket to spread the end of the tube slightly. Then before reinstalling the tube, apply high strength liquid threadlocker to permanently secure it in place in the aluminum holder.

Checking the Accuracy of the Oil Dipstick -

The engine is at full capacity of oil at 3/8" above the oil pan gasket for the 7hp and 8hp Kohler engines, and 1/2" above the oil pan gasket for the 10hp-16hp Kohler engines. If in doubt about the accuracy of the 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 an adjustment to the dipstick needs to be made. This method removes all guesswork. And always fill an engine with oil to the FULL mark on the dipstick.

But for a competition pulling engine, ask yourself these two questions: How many times does one have to add oil to a pulling engine? And as long there's no major oil leaks, why have a dipstick? Just know how much oil your engine holds, and have a way on the engine block to install the oil after every oil change.

In rare cases, the oil dipstick isn't accurate or calibrated right. 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 the rod to burn on the crankshaft.) And also, sometimes a dipstick will get lost (kids playing with the lawn mower) or get broken, and a wrong replacement is used, but it's not calibrated right like the original dipstick. Return È


Performing a Compression Test on a Stock or High-Performance Engine -

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 lump (B&S, some Tecumseh, etc.) or mechanical lever/pin (Kohler, some Tecumseh, etc.) on one of the camshaft lobes that holds either the exhaust or intake valve open about .050" while the piston is traveling halfway up in the cylinder on the compression stroke. On OEM camshafts with a working compression release mechanism and if the valves are adjusted to specs, the compression release releases about half the compression from the combustion chamber at cranking speeds. This is so the engine will start easier with fixed advanced ignition timing. 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.

There are two ways to perform an accurate compression test with a compression gauge on the Kohler K-series and Magnum models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) flatheads and K361 (OHV 18hp) engines:

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 postion. 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 on an engine under compression, the 10hp Kohler can be from 98 to 150 psi. On a 12hp, it can be from 112 to 170 psi. On a 14hp, it can range from 120 to 190 psi. And on a 16hp, it can be from 127 up to 192 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.


How to Prepare an Engine for Wintertime or Long-Term Storage -

  1. First of all, prepare a cool, dry place of storage with low humidity to lesson the chance of corrosion and rust.
  2. Drain the entire fuel system from the equipment being stored. This includes the carburetor float bowl, fuel pump, fuel line, fuel filter and fuel tank. Leave the hose(s) disconnected so the entire fuel system will totally dry out.
  3. If the engine is equipped with an electric or mechanical fuel pump, apply about a teaspoon-full of clean automatic transmission fluid in the pump so the pump diaphragm will remain flexible or rotor vanes will won't stick and to prevent the poppet valves from sticking or becoming corroded.
  4. Remove the spark plug, squirt about a teaspoon-full of clean automatic transmission fluid (ATF) into the combustion chamber.
  5. Reinstall the spark plug and crank the engine several revolutions to evenly distribute the oil on the cylinder wall, valves, seats and valve stems (guides). (Automatic transmission fluid contains a rust inhibitors so the engine parts won't corrode or rust.)
  6. Run the piston up at TDC on the compression stroke. Doing this will prevent the valves from sticking open, and the valve springs won't be under extreme pressure.
  7. And that's all that's to it!


Removing the Variator from an Engine -

The variator (drive half of a torque convertor 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.


Kohler Engine Service & Repair Manuals
Contains all the information needed to disassemble, repair and reassemble your Kohler engine.

  • General Information
  • Special Tools
  • Periodic Maintenance
  • Troubleshooting
  • Air Cleaner and Air Intake System
  • Fuel System and Governor
  • Retractable Starter
  • Electrical System and Components
  • Automatic Compression Release
  • Disassembly
  • Inspection and Repair
  • Reassembly

By clicking on Download, a new website opens containing the manual in PDF file format, which can be printed out.
(Requires Adobe Acrobat Reader and use Google Chrome web browser for a faster download of web sites with large files.)

  • Covers K-series models K90/K91-K341. OEM Kohler part # TP-2379. $30.00 each, plus shipping & handling. Download
  • Covers Magnum models M8-M16. OEM Kohler part # TP-2203-A. $30.00 each, plus shipping & handling. Download
  • Covers K-series model K361. OEM Kohler part # TP-1288. $30.00 each, plus shipping & handling. Download
  • Covers models KT17, KT17II, KT19, KT19II and KT21 Series I and II. OEM Kohler part # TP-2043-A. $30.00 each, plus shipping & handling. Download
  • Covers Magnum models M18 and M20. OEM Kohler part # TP-2204-B. $25.00 each, plus shipping & handling. Download
  • Covers models K482, K532, K582 and K662. OEM Kohler part # ENS-607. $25.00 each, plus shipping & handling. Download
  • Covers models CH18-CH750 COMMAND TWIN. OEM Kohler part # 24 690 06. $25.00 each, plus shipping & handling.
  • Covers models CV11-16/CV460-465/CV490-49. OEM Kohler part # 12 690 01. $25.00 each, plus shipping & handling.
  • Covers models COURAGE XT-6/XT-7. OEM Kohler part # 14 690 01. $25.00 each, plus shipping & handling.
  • Covers models CH270/CH395/CH440. OEM Kohler part # 17 690 01. $25.00 each, plus shipping & handling.
  • Covers model COURAGE SH265. OEM Kohler part # 18 690 01. $25.00 each, plus shipping & handling.
  • Covers models SV470-SV620 COURAGE. OEM Kohler part # 20 690 01. $25.00 each, plus shipping & handling.
  • Covers models ECH630-ECH749 COMMAND PRO. OEM Kohler part # 24 690 01. $25.00 each, plus shipping & handling.
  • Covers models ECV630-ECV749, CV735, CV26, CV745 CO. OEM Kohler part # 24 690 02. $25.00 each, plus shipping & handling.
  • Covers models CV17-CV26,CV620-CV750 COMMAND TWIN. OEM Kohler part # 24 690 07. $25.00 each, plus shipping & handling.
  • Covers models SV710-740, SV810-840 COURAGE. OEM Kohler part # 32 690 01. $25.00 each, plus shipping & handling.
  • Covers models CH940-CH980 COMMAND PRO. OEM Kohler part # 62 690 01. $25.00 each, plus shipping & handling.
  • Covers models CV940-CV1000 COMMAND PRO. OEM Kohler part # 62 690 02. $25.00 each, plus shipping & handling.
  • Covers models CS4-12.75 COMMAND PRO CS. OEM Kohler part # 63 690 01. $25.00 each, plus shipping & handling.
  • Covers models LH630-LH775. OEM Kohler part # 66 690 01. $25.00 each, plus shipping & handling.
  • Covers model LH775 EFI. OEM Kohler part # 66 690 07. $25.00 each, plus shipping & handling.
  • Covers models LH630-LH775. OEM Kohler part # 66 690 01. $25.00 each, plus shipping & handling.


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 need any of the services listed below Ê performed, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.

Precision Dynamic Spin-Balancing Service. To balance a rotating assembly, I need the crankshaft, piston/rings, pin, clips, connecting rod and bearing inserts. The flywheel is balanced separately.

  • Balance cast crankshaft - $125.00 labor (mallory extra).
  • Balance steel crank - $150.00 and up (mallory extra).
  • Balance flywheel (steel or cast) - $50.00 labor.

Engine Block -

  • Bore cylinder to fit next oversize piston (OEM engine block). $60.00 labor per cylinder.
  • Bore cylinder to fit aftermarket piston (new aftermarket [Kohler] block). $120.00 labor.
  • Clearance bottom cylinder bore for stroker crankshaft. $75.00 labor.
  • Bore cam pin holes to 11/16" (.6875") for installation of needle bearings (OEM or aftermarket [Kohler] block). $50.00 labor.
  • Remove welch plug and cut threads for auxiliary crankcase breather (OEM and aftermarket [Kohler] block. $20.00 labor.
  • Clean block. $7.00 labor.
  • Drill and tap two 5/16"-18 holes in exhaust flange (to mount header pipe). $40.00 labor, plus return shipping & handling.
  • Resurface exhaust mounting flange (to insure sealing of header flange). $10.00 labor.
  • Drill 7/8" center hole and two outer 1/4" bolt holes in 10-16hp Kohler blocks to mount mechanical fuel pump. $50.00 labor.
  • Drill and tap stripped 3/8" NPT aluminum oil pan drain plug hole to 1/2" NPT plug. $6.00 parts & labor. Includes 1/2" NPT square head plug.

Convert 10-16hp Kohler wide base block to narrow base, for use in a garden tractor requiring a narrow base engine block.

  • Cut off flanges and grind remaining metal even with block. $50.00 labor, plus return shipping & handling.
  • Cut off flanges, grind remaining metal even with block and cut threads in oil pan mounting holes. $60.00 labor, plus return shipping & handling.
  • Cut off flanges, weld-in steel stock to fill in oil-fill holes, grind remaining metal even with block and cut 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 -

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

Cylinder Head Work -

  • Resurface air-cooled small engine cylinder head to remove warpage. $7.00 labor, plus return shipping & handling.
  • Bead-blast (thoroughly clean) and resurface air-cooled small engine cylinder head. $15.00 labor, plus return shipping & handling.
  • Mill cylinder head approximately .050". Remove 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. Click photo to the right for a larger view. NOTE: Seal the head gasket with 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.
  • Repair stripped spark plug threads. No need to purchase another cylinder head. $5.00 - $20.00 each (depending on size of hole and type of head) for parts 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.
  • 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, and then the connecting rod can be resized so it'll fit the smaller undersize journal. 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. The cost for having this done is $100.00 labor for a single cylinder engine, and $200.00 for a two cylinder engine, plus return shipping & handling. If you're interested, we will need your crankshaft and connecting rod(s). An innovative concept by Brian Miller, because nobody else advertise this service.
    • Once installed and in operation, there is no warranty or guarantee of any kind on crankshaft regrinds.
  • 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 NF threads in the PTO end of the crankshaft for a retaining bolt and flat washer. $20.00.


Bare Kohler K-series Engine Blocks (when available) - Top of page

  • K141 (6¼hp), K161 (7hp ) & K181 (8hp) bare blocks with 2-15/16" bore. $40.00 each, plus shipping & handling.
  • K241 (10hp) bare block. $65.00 each, plus shipping & handling.
  • K241 (10hp) bare block with 10hp bore and K301 embossed on the PTO end. (Extra thick cylinder wall.). $200.00 each, plus shipping & handling.
  • K301 (12hp) bare block. $125.00 each, plus shipping & handling.
  • K321 (14hp) bare block. $150.00 each, plus shipping & handling.
  • K341 (16hp - 12 fin) bare block. $250.00 each, plus shipping & handling.
  • K341 (16hp - 13 fin) bare block. $400.00 each, plus shipping & handling.
  • Packaged shipping weight for each block is 25 lbs.

The Major Differences Between the K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp) and K341/M16 (16hp) 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.

Kohler engine blocks are not like the small block Chevy V8, they're not all the same. There are many other variations between the Kohler K241/M10, K301/M12, K321/M14 and K341/M16 blocks. If replacing an engine, the best thing to do is have the original engine rebuilt, then all the accessories will attach to the engine with no problems. But if the block is not rebuildable and damaged beyond repair, another block of the same type will need to be acquired. If interested in purchasing a bare block, please email me several detailed, sharp pictures of your block at various angles so I match it to one I may have in stock.
  • Some blocks have wide base flanges (for the wide, deep oil pan) and some have a narrow base with no flanges (for a Cub Cadet or John Deere oil pan).
  • The very early K241 blocks have no indentation for installing an upper mount gear starter. Also, some of these older blocks with flanges have no holes drilled for converting to a narrow base oil pan. (But the holes can be drilled and tapped.)
  • Some blocks have the oil dipstick tube hole next to the cylinder, above the crankcase, while others have no hole present. The hole is either drilled or threaded. Some blocks have provisions for a starter-side oil dipstick tube, and some don't.
  • Some blocks come with balance gears and some didn't. Some have an expansion plug where balance gear stub shafts can be installed, and some have no holes drilled for the stub shafts.
  • 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.
  • The threaded holes on the PTO end of the block can have different bolt patterns.
  • 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 above È, everything else on the Kohler K-series engine blocks are pretty much the same.

Advertisement:
Miller's Engine Refreshing, Rebuilding, and Build-up Service -
If you need your engine rebuilt or built up for general yard and garden work or competition pulling so it'll produce more power and torque, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
Engine Rebuilding Service -

I rebuild engines from ordinary stock up to 4,000 rpm governored pulling engines. I can rebuild your engine however you want. Just tell me know how you're going to use your tractor or equipment and I'll build your engine to suit your needs. If you wish to have me rebuild or build-up your engine, I'll need a list of 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. I'll build your engine to the limit according to the rules, not less than what the rules allow. I also rebuild ordinary lawn & garden equipment engines too, such as cast iron and aluminum block single- and twin-cylinder flathead, OHV and v-twin Briggs & Stratton, Kohler, Tecumseh and 2-cycle LawnBoy. I've never encountered an engine I couldn't repair!

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!

All customer's pulling engine builds are strictly confidential. This means your pulling competition will not know what goes into your engine!

IMPORTANT!

Break-In Oils and Procedure for Ordinary (Lawn & Garden) Engines -

For proper break-in of a new or freshly rebuilt engine, use conventional (petroleum-based) SAE 30 weight motor oil containing an anti-wear additive, such as ZDDP (Zinc dithiophosphate), which place 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. 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. Then drain the oil while it's hot, and 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. 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.

Break-In Oils and Procedure for Pulling Engines -

For proper break-in of a freshly built or rebuilt pulling engine, use conventional (petroleum-based) SAE 30 weight motor oil containing an anti-wear additive, such as ZDDP (Zinc dithiophosphate), which place 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. Run the engine normally (up to 4,000 rpm) for 4-5 pulls. Then drain the oil while it's hot, and either continue to use ordinary SAE 30 oil, or switch to a quality 10W40 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.

And Remember... (added paragraph below on 7/13/14)

Rather if it's for competition pulling or for general yard and garden use, any fresh-built engine needs to fully break-in. Rings break-in quickly. But the valve faces needs to wear into the seats to seal in the compression 100%. The harder material the valves are made of, the longer it takes for them to "seat." 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, but I noticed it produced a little more power after 1,000 or so miles. This is because the valve faces wore into the seats, forming a perfect seal. So just to let you know, a fresh-built engine will not produce full power the first few times it's ran.

Below Ê are details and prices to rebuild your engine - FYI - Being I'm the only person to read and respond to all my customer's emails (about 20 or so per day), take my customer's phone call orders (about 20-30 on a nice day with good weather), with customers stopping by my shop, repair and rebuild my customer's parts and engines in my shop, order parts from my suppliers, process orders, package parts and then mail customer's parts at my local Post Office, etc., it may take me several months, possibly up to 6 months to rebuild an engine. I also have to depend on other local machine shops to balance engine parts, perform various machine work that I can't do myself. All this takes time. So please keep this in mind if you decide to have me rebuild/build your engine. Also, I don't like to rush on my customer's repair jobs. I'm very particular about my work, especially my engine builds. I like to take my time to make sure that everything is right, the engine will run right, produce full power and last a long time. I appreciate for you understanding my situation. - Brian Miller
If you need your engine rebuilt or built up for general yard and garden work or competition pulling so it'll produce more power and torque, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO 65203-9136 USA | Phone: 1-573-875-4033. 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.) Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Send a message with Yahoo Messenger: | Directions to our shop | Yahoo! Maps, 1501 W. Old Plank Rd., Columbia, MO | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Click here for more parts and services. | NOTE: To place an order, please call or send an email with a list and description of the parts or services you need. Because as of right now, we're not set up to accept orders through our web sites online. Due to the rising cost of... everything, prices are subject to change.
Briggs & Stratton 3hp to 5hp flathead aluminum block engine (horizontal or vertical shaft) rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work only) Your engine.
  • $75 - $100±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $100 - $150±, includes labor and genuine OEM B&S parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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 & labor (if rebuildable).

Briggs & Stratton 7hp through 12.5hp single cylinder flathead aluminum block engine (horizontal or vertical shaft) rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work only) Your engine.

  • $250±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $300±, includes labor and genuine OEM B&S parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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 & labor (if rebuildable).

Briggs & Stratton 16, 18 & 20hp flathead/opposed twin cylinder aluminum block engine (horizontal or vertical shaft) rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $350±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $450±, includes labor and genuine OEM B&S parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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 & labor (if rebuildable).

Briggs & Stratton Vanguard V-twin aluminum block engine (horizontal or vertical shaft) rebuild to OEM factory specifications @ 3,200 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $700±, includes labor and genuine OEM B&S parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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 & labor (if rebuildable).

Briggs and Stratton cast iron block engine model 23 (newer models 231401-233461) or model 24 (newer models 243431-243457) rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $800±, includes labor and genuine OEM B&S parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new .020" oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod, resurface cylinder head, rebuild carburetor, install tune-up kit or NOVA 2 module, install new gaskets and oil seals. If engine has a broken connecting rod, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable).
Tecumseh 3hp to 10hp flathead aluminum block engine (horizontal or vertical shaft) rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work only). Your engine.
  • $75 - $400± (depending on size of engine and extent of wear), includes labor and high quality aftermarket parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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 & labor (if rebuildable).

Tecumseh 8hp (VH80/HH80), 10hp (VH100/HH100), 12hp (HH120/OH120), 14hp (OH140), 15hp (OH150), 16hp (OH160) & 18hp (OH180) flathead & OHV cast iron block engines (horizontal & vertical shaft) rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work only). Your engine. (Prices depends on size of engine and extent of wear.)

  • $500 - $800±, includes labor and high quality aftermarket parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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 & labor (if rebuildable).
NOTE: If you wish to have me rebuild or build-up your engine, I will need a list of 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. I'll build your engine to the limit according to the rules so the engine will be competitive, not less than what the rules allow.

Kohler K90 (3.6hp), K91 (4hp) cast iron block flathead engine rebuild to OEM factory specifications @ 4,000 governed rpm (for general yard work). Your engine.

  • $250±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; regrind crank journal and resize connecting rod; resurface cylinder head; rebuild carburetor; install tune-up kit; install new gaskets and oil seals. If engine has a broken connecting rod, and internal damage has resulted, the price will be slightly higher for additional parts and labor (if rebuildable).

Kohler K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp) cast iron block flathead engine rebuild to OEM factory specifications @ 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $300±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $400±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; regrind crank journal and resize connecting rod; resurface cylinder head; rebuild carburetor; install tune-up kit; install neoprene rubber seal in governor shaft bushing; 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 K-series and Magnum models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp) cast iron block flathead engines rebuild to OEM factory specifications @ up to 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $500±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $800±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; regrind crank journal and resize connecting rod or install new matching undersize rod or fit connecting rod w/bearing inserts; resurface cylinder head; rebuild carburetor; install tune-up kit; install neoprene rubber seal in governor shaft bushing; 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 K-series and Magnum models K241/M10 (10hp), K301/M12 (12hp), K321/M14 (14hp) or K341/M16 (16hp) cast iron block flathead engines Stock-Appearing engine build to the max @ up to 4,000 rpm (for heavy yard work or competition pulling). Your engine.

  • $1,200±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $1,500±, includes labor and genuine OEM Kohler parts parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; install medium performance valve springs; regrind crank journal and install bearing inserts in connecting rod; mill cylinder head; rebuild or bore-out and rework carburetor; install tune-up kit, install neoprene rubber seal in governor shaft bushing; 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). Add A-1 Miller's NEW and IMPROVED Crank Trigger Ignition System. $95.00 each. (For competition pulling only.)

Kohler K-series and Magnum models K341/M16 (16hp) cast iron flathead block engine rebuild to OEM factory specifications @ up to 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $600±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $900±, includes labor and genuine OEM Kohler parts parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; regrind crank journal and resize connecting rod or install new matching undersize rod or fit connecting rod w/bearing inserts; resurface cylinder head; rebuild carburetor; install tune-up kit; install neoprene rubber seal in governor shaft bushing; 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). Add A-1 Miller's NEW and IMPROVED Crank Trigger Ignition System. $95.00 each. (For competition pulling only.)

Kohler K-series K361 (18hp) cast iron block single cylinder OHV engine. Rebuild to OEM factory specifications @ up to 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $1,000±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly; regrind valves and seats; regrind crank journal and resize connecting rod or install new matching undersize rod or fit connecting rod w/bearing inserts; resurface cylinder head; rebuild carburetor; install tune-up kit; install neoprene rubber seal in governor shaft bushing; 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). Add A-1 Miller's NEW and IMPROVED Crank Trigger Ignition System. $95.00 each. (For competition pulling only.)

Kohler K-series and Magnum models MV16, KT17II, KT19II, M18, MV18, M20 and MV20 opposed cast iron twin cylinder flathead engines. Rebuild to OEM factory specifications @ up to 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $700±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston rings, regrind valves and seats, install new valve guides (if needed), resurface cylinder heads, 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 pistons 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, I don't have the cylinders bored oversize and install new oversize pistons and rings because this would be too cost prohibitive being I have good used cylinders and pistons in stock.

Kohler K-series engine models K482, K532 and K582 opposed cast iron block twin cylinder flathead engines. Rebuild to OEM factory specifications @ up to 3,600 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $1,000±, includes labor and high quality aftermarket parts, return shipping & handling extra.
  • $1,400±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinders and install new oversize pistons/rings assembly, regrind valves and seats, regrind crank journals and resize connecting rods (if needed), resurface cylinder heads, rebuild carburetor, 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 higher for additional parts and labor (if rebuildable).

Kohler Command 25hp V-Twin engine. Rebuild to OEM factory specifications @ up to 3,200 governed rpm (for general yard work or mild competition pulling). Your engine.

  • $700±, includes labor and genuine OEM Kohler parts, return shipping & handling extra.
    • Parts and labor includes: Install new STD size piston/rings assembly or bore cylinder and install new oversize piston/rings assembly, regrind valves and seats, regrind crank journal and resize connecting rod, install new matching undersize rod or fit connecting rod w/bearing inserts (if available for a particular engine), resurface cylinder head, rebuild carburetor, 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).
Competition Pulling Engine Refreshing Service Ê A typical pulling engine will last an average of 25 pulls or 3 years of use. After that, it may start to lose power when under load and puff smoke out the crankcase breather vent and/or out the exhaust. When this happens, it's time for a refreshing job. This service is for competition pulling engines that have been previously built, and needs the basic parts to revive the power. It is not a complete rebuild.

Refresh Stock "Built to the max" 10-16hp 4,000± rpm Governored Kohler pulling engine. Includes install new rings or piston and rings; perform performance valve job; install new bearing inserts; clean, rebuild or rework/bore-out carburetor; install our reground 4,000 rpm torque camshaft; new gaskets and oil seals.

  • $200.00 labor, plus return shipping & handling. Parts installed are extra charge.

Refresh Hot Stock or Stock-Altered 12-16hp Kohler engine. Includes install new rings or piston and rings; perform performance valve job; new bearing inserts; clean or rebuild carburetor; if needed, install our welded up and reground Hot Stock/Stock Altered camshaft; new gaskets and oil seals.

  • $300.00 labor, plus return shipping & handling. Parts installed are extra charge.

Refresh NQS 30 c.i. Kohler engine. Includes install new rings or piston and rings; perform performance valve job; new bearing inserts; clean or rebuild carburetor; install new up-to-date Lakota, MWSC or Vogel camshaft; new gaskets and oil seals.

  • $400.00 labor, plus return shipping & handling. Parts installed are extra charge.
  • Add $200.00 labor to machine valve cavities deeper in billet cylinder head if a new camshaft with more lift will be installed.

Refresh Missouri Super Stock 16hp Kohler engine. Includes install new rings or piston and rings; perform performance valve job; new bearing inserts; clean or rebuild carburetor; new up-to-date Lakota, MWSC or Vogel camshaft; new gaskets and oil seals.

  • $400.00 labor, plus return shipping & handling. Parts installed are extra charge.
  • Add $200.00 labor to machine valve cavities deeper in billet cylinder head if a new camshaft with more lift will be installed.

Refresh 50.5 c.i. 16hp Kohler engine. Includes install new rings or piston and rings; perform performance valve job; new bearing inserts; clean or rebuild carburetor; new up-to-date Lakota, MWSC or Vogel camshaft; new gaskets and oil seals.

  • $500.00 labor, plus return shipping & handling. Parts installed are extra charge.
  • Add $200.00 labor to machine valve cavities deeper in billet cylinder head if a new camshaft with more lift will be installed.
Stock and Hot-Stock Class Competition Pulling Engines Ê Top of page

The below are very powerful engines, and built and designed for competition pulling only, not general yard work. 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 4,000± governored rpm; has a 9-1/2" cast flywheel with majority of fins removed then dynamically precision spin-balanced; upper-mount gear starter; 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; 2nd or 3rd generation cylinder head milled .050"; connecting rod bored .020" offset for piston pop out with bearing inserts; header pipe and conventional Kohler point ignition system installed with ignition timing preset.

The Hot-Stock class engines runs at wide open throttle (no governor); has a 9-1/2" 25 lb. steel flywheel; upper-mount gear starter; A-1 Miller's Hot-Stock welded-up and reground camshaft; high-performance valve springs; performance valve job with stock size valves; #26 or #30 Kohler carburetor (depending on engine size) bored-out, reworked and set up for gas; enlarged ports and polished; 2nd or 3rd generation cylinder head milled .050"; connecting rod bored .020" offset for piston pop out with bearing inserts; rotating assembly precision spin-balanced (to reduce engine vibration); header pipe and conventional Kohler point ignition system installed with ignition timing preset.

  • 10hp Built to the max Stock Engine. Produces ± 15hp@ 4,000 rpm and 19 ft. lbs. of torque @ 4,000 rpm. $800±, plus crating and FedEx Ground® shipping.
  • 12hp Built to the max Stock Engine. Produces ± 22hp@ 4,000 rpm and 29 ft. lbs. of torque @ 4,000 rpm. $1,200±, plus crating and FedEx Ground® shipping.
  • 12hp Hot-Stock Engine. Produces ± 32hp@ 6,500 rpm and 26 ft. lbs. of torque @ 5,500 rpm. $2,200±, plus crating and FedEx Ground® shipping.
  • 14hp Built to the max Stock Engine. Produces ± 25hp@ 4,000 rpm and 33 ft. lbs. of torque @ 4,000 rpm. $1,400±, plus crating and FedEx Ground® shipping.
  • 14hp Hot-Stock Engine. Produces ± 34hp@ 6,500 rpm and 28 ft. lbs. of torque @ 6,500 rpm. $2,400±, plus crating and FedEx Ground® shipping.
  • 16hp Built to the max Stock Engine. Produces ± 28hp@ 4,000 rpm and 37 ft. lbs. of torque @ 4,000 rpm. $1,600±, plus crating and FedEx Ground® shipping.
  • 16hp Hot-Stock Engine. Produces ± 38hp@ 6,500 rpm and 33 ft. lbs. of torque @ 5,000 rpm. $2,600±, plus crating and FedEx Ground® shipping.
  • NOTE: ± means more or less, depending on your pulling club's engine rules and restrictions. Engines are built as customers order them according to their tractor's make and model. Your pulling club's engine rules and requirements will be needed so the engine will be legal within its class. And I don't offer any chrome-plated sheet metal or header pipes because these parts are cost-prohibited. Add A-1 Miller's NEW and IMPROVED Crank Trigger Ignition System. $95.00 each. (For competition pulling only.)
Custom-Built Cub Cadet Garden Pulling Tractors -
  • Complete Stock Class Pulling Tractor. $4,000 - $6,000 ±
  • Complete Hot-Stock/Stock-Altered Class Pulling Tractor. $7,000.00 - $10,000 ±
  • Complete Missouri Super-Stock Class Pulling Tractor. $12,000.00 - $15,000.00 ±
  • ± means more or less. Price depends on your pulling club's sanctioning rules and your personal preferences. Includes engine, transaxle, tires/wheels, and entire tractor. (Click image to the right for a larger view.)
  • A 50% deposit is required on all pulling tractor orders. Balance due at pick up upon completion of tractor. (No shipping or delivery.)

NOTES:

To place an order, please call or email me 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, I accept cash (in person), Postal money orders, cashier's checks, MasterCard, VISA, Discover, American Express and Western Union Money Transfer. (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 me 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.

IMPORTANT! If you bring an engine to me in person, sit it in an automotive tire to keep it from moving around during transportation. And please let me 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 & need rebuilding or reconditioning, such as the gear starter, cylinder head(s), crankcase breather assembly, fuel pump & carburetor. I need the oil pan on it too, to prevent any dust and dirt from entering the crankcase after the rebuild. Please remove the 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. If shipping it, the average crated cast iron block Kohler engine weighs just under 150 lbs. Use this web site to calculate the shipping cost for your engine: http://www.shipgooder.com/. Use FedEx Ground for dependability. Do not use a cardboard box alone! Crate it well and any other parts with it securely so they won't get damaged or lost in shipping. To construct the wooden crate, use 2x2's or 2x4's for the frame work with a skid pallet on the bottom (so a forklift can pick it up without damage) and 1/4" plywood or paneling as covering. Fasten the engine oil pan mounting bolt holes to two sturdy 2x4's on the base of the crate securely with 3/8" bolts. Use extra bracing on the sides and/or across the top of the engine if needed to stabilize it in the crate. Use screws to fasten everything. And 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 what you want done, how the engine will be used & any other parts you may need. When the work is completed, I'll contact you with the total including return shipping and handling. For payment, I accept cash (in person), USPS Postal Money Orders, cashier's checks, MasterCard, VISA, Discover, American Express and Western Union Money Transfer. (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 me 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. And I will ship your rebuilt engine/parts to you as soon as I receive your payment.

To ship your engine to us, first off, do not use the US Mail Service, UPS or FedEx Express! We and our customers have had too many problems with them in the past. They wouldn't even make good on the insurance either. Their "gorillas" (employees) are trained in handling lightweight packages (weighing up to 70 lb.) and the heavier items tend to get damaged with their kind of handling. They are very hard on 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.

We're authorized FedEx Ground (for anything up to 150 lbs.) and FedEx Freight (for anything over 150 lbs.) shippers 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) and the crated weight of a typical complete 10-16hp Kohler engine (145 lb.). Shipgooder doesn't ship anything. It's web site just lets you see the latest cost of various shipping companies. Contact your local FedEx Ground 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 with their uncaring "gorillas" unloading and loading 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.


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


A-1 Miller's Performance Enterprises Offering Quality Products and Professional Workmanship at Reasonable Prices!

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