Please visit these other Brian Miller's websites:
A-1 Miller's Performance Enterprises - Parts & Services Online Catalog | Miller's ATV, UTV and Local/Stock Garden Tractor Pulling Sled Rental | Hot Rod Garden Tractor and Mini-Truck Pullers Association

Copyright © 1996-Present. This website created, designed and maintained by Brian Miller.

Important Information About Small Engine Flywheels

This website was updated 8/2/17. (Click Refresh to see changes or updates.) Optimized for 1024 x 768 screen resolution. To search for a word or phrase in any of my web sites, with Microsoft Internet Explorer 6.x, or Google Chrome, press CTRL+F to open the Find dialog box. Although every effort has been taken to check the accuracy of information contained herein, I cannot assume responsibility for errors.


First of all, the flywheels on Kohler K-series and Magnum engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361 will interchange, because the tapers and keyway widths are the same. The only difference is the type of starter and ignition system used. Some engines with a rope starter have magneto ignition and a 9-1/2" flywheel with no ring gear; other engines with a starter/generator and battery ignition, use either a 8" or 9-1/2" flywheel with no gear ring; some early engines with magneto ignition have a 9-1/2" flywheel with no ring gear; while most later K-series engines have battery ignition, and a 9-1/2" ring gear flywheel with internal magnets for an alternator charging system. Also, all Kohler Magnum M10-M16 engines use the same flywheel. The Kohler KT-series twin cylinder flathead engine models KT17, KT17 series 2, KT19, KT19 series 2 and KT21 (which is a snowmobile engine) use the same flywheel. And the Kohler Magnum twin cylinder flathead engine models M18 and M20 use the same flywheel.

Four types of flywheels were used on the K241-K361 K-series Kohler engines. They are as follows:

  1. From 1960 to 1973, many of the K241 and K301 engines came with an 8" diameter flywheel. The engine had battery-powered ignition, and a starter/generator provided the cranking source to start the engine and then it produced the power source to recharge the battery and power any electrical accessories. These were popular with the narrow- and wide-frame (with solid-mounted engine) IH Cub Cadets.
  2. Very few of the early K241 and K301 engines came with a 9-1/2" diameter flywheel with an unmachined edge for a starter ring gear, and there's no way to install a ring gear. These engines had a magneto ignition system. There's two magnets attached to inside the flywheel, the ignition coil is fastened on a stator to the bearing plate and a rope was used on a large notched pulley that's attached to the flywheel to crank the engine. There is no battery and no charging system involved. These were used on self-contained, stand-alone engine units, such as truck-mounted air compressors, generator/welders, water pumps, etc., and they were popular with the U.S. Military because there was no recoil starter and very few ignition parts to give trouble. Certain ignition coils are no longer available from Kohler for these engines.
  3. Another 9-1/2" diameter flywheel with an unmachined edge for a starter ring gear was also used on very few of the early K241 and K301 engines. There's no magnets inside the flywheel and no [magneto] stator. The engine had battery-powered ignition, and a starter/generator provided the cranking source to start the engine and then it produced the power source to recharge the battery and power any electrical accessories. These are popular with certain models of Case garden tractors.
  4. In 1974, the K241-K361 engines came with a 9-1/2" diameter flywheel with a machined edge for a starter ring gear and a ring of magnets on the inside. The engine had battery-powered ignition, and a small, gear type starter motor cranks the engine to start it and an alternator charging system produced the power source to recharge the battery and power any electrical accessories. These were popular with the wide-frame "Quiet Line" IH-built Cub Cadets and certain spread-frame MTD-built Cub Cadets.

And the K-series and Magnum flywheels have the same overall dimensions. The only difference is, the K-series flywheel has integrated fins (fan blades) and the Magnum flywheel use a bolt-on plastic fan blade unit, and it has an integrated magnet for the solid state ignition. The starter ring gear will also interchange between the two flywheels. As a matter of fact, the same ring gear fits the K241/M10-K341/M16 and K361 K-series and Magnum single cylinder engines, and the KT-series and Magnum twin cylinder engines.

FYI - A cast iron flywheel with a broken fin (fan blade) will definitely run out of balance, and cause the entire engine to vibrate badly. It could also cause the crankshaft to break. To put the flywheel back in balance, simply break off the fin directly across from the broken one is with a hammer. Try to make sure that one broken fin matches the height of the other to maintain the balance. The flywheel should still be safe to use, and the remaining intact fins will produce plenty of fresh air to adequately cool the engine. But the best way to put the flywheel 100% back in balance is to have it dynamically precision spin-balanced with an automotive crankshaft/flywheel balancing machine.


The Safe and Correct Way to Remove a Small Engine Flywheel -

To remove the flywheel from a Kohler (or virtually any) small engine, remember, the retaining nut or bolt have right-hand threads. And there's either 5/16-18 UNC (small flywheels) or 3/8-16 UNC (large flywheels) bolt holes for use with grade 8 bolts with a flat washer and a quality-made gear puller to remove the flywheel from the crankshaft. A hand tap may need to be used to clean the dirt and debris from the threads in the bolt holes. Remove the flywheel with a quality-made automotive harmonic balancer/vibration damper puller tool (Lisle Corporation makes a quality puller) that have fine threads and with a quality-made 1/2" impact wrench (with a large capacity [minimum 30 gallon] air compressor reservoir tank) to literally "pop" the flywheel off the crankshaft taper. Be sure the puller bolt is centered on the crankshaft, too. Avoid using an low-quality imported puller because it might move sideways when under pressure and break off the stud or bend the bolt. Use the protective cap that's supplied with the puller to prevent from damaging the threads on the end of the crankshaft. Apply grease or motor oil on the threads of the center threaded shaft to increase the pulling torque. The puller tool require either two 5/16" or two 3/8" diameter grade 8 coarse thread bolts with a thick flat washer under each bolt head so the head won't pull through the puller's slots. And use bolts that's long enough so the threads can penetrate the entire length of the threaded holes in the flywheel to prevent the threads from being pulled out. Use a tap to clean the threads in the flywheel if necessary. And although some flywheels are stubborn to remove, just remember, it'll eventually come off. It's not made on the crankshaft!

Personally, I use a quality-made 1/2" impact wrench running off of 150 psi of pressure with a 60 gallon air compressor tank and a Lisle harmonic balancer puller with grade 8 bolts w/flat washers threaded deep into the flywheel threads to remove Kohler flywheels. I ain't never had one that was so stubborn it took a lot of effort to remove. My set up pops them off every time with very little effort! You can hear the air impact wrench when it gets under a severe strain, it starts to slow down and then POW, the flywheel pops loose.

On most aluminum block engines, such as Briggs & Stratton, Tecumseh, etc., a flywheel knock-off tool can be used to remove the flywheel. You can get a knock-off tool at virtually any place that sells small engine parts, and they come in 4 different sizes: 1/2" hole for older B&S engines, 7/16-20 UNF, 1/2-20 UNF and 5/8-18 UNF.

To use the knock-off tool, for an older B&S engine with the crankshaft that has a long unthreaded shaft that protrudes into the starter clutch, the tool is placed on the end of the shaft, and for all other engines with a threaded stud on the end of the crankshaft, the tool is threaded onto the stud. A crowbar or pry bar is wedged under the flywheel against the engine block to provide extra leverage (and to prevent breaking the rod journal on the crankshaft if it's cast iron or bending the crankshaft if it's steel), then a 2-3 lb. hammer is used to sharply strike the tool perpendicular to literally "pop" the flywheel free from the crankshaft taper. To prevent from damaging the threads in the tool and on the crankshaft stud, always thread the tool all the way on the stud, and then back it off 1/2 turn. And don't strike the knock-off tool at an angle, or the stud on the crankshaft could get bent or break off!

But on flywheels with no threaded holes to use the automotive harmonic balancer/vibration damper puller tool, a knock-off tool of the correct thread size with a pry bar wedged under the flywheel and a 2-3 lb. hammer can be used to remove the flywheel. Be sure to strike the tool perpendicular, too!

IMPORTANT! The Incorrect and Dangerous Way To Remove A Small Engine Flywheel -

Most Kohler crankshafts are made of somewhat brittle cast iron material. So NEVER hit or strike the end of the crankshaft with a big hammer to remove a flywheel! And DO NOT attempt to use a wrecking bar (crowbar) to "pry" the flywheel off the crankshaft! Also, never use a large [2 or 3 jaw] outside gear puller to remove a flywheel. Doing any of these could break or crack the crankshaft and/or possibly crack the flywheel or break it in half. AND DEFINITELY DO NOT USE A KNOCK-OFF TOOL WITH A BIG HAMMER ON A KOHLER CRANKSHAFT WITH THE 5/8" STUD TO REMOVE THE FLYWHEEL! Being the crank is made entirely of cast iron, the stub will likely to break off!

A true story: One of my customers brought his walk-behind rotary lawn mower with a 3.5hp Tecumseh engine (model LAV35) to me just to have the flywheel removed. When I had the mower on my work table to remove the flywheel, I noticed the flywheel was wobbly but still tight on the crankshaft. Then I found that the crankshaft was broken in two at the connecting rod journal. I thought, "This is odd." So I called my customer to tell him about this, and he said his neighbor tried to "pop" the flywheel off with a 10 lb. sledge hammer. (This obviously happened with the mower on the ground and the threaded end of the crankshaft was hit by the hammer at full swing.) Reminds me of the old joke: "Hold my beer and watch this!"


About Crankshafts Breaking at High RPM -

A stock crankshaft should be fine as long as the engine isn't over-revved for a long period of time, which could cause it to go into harmonic vibrations, which would cause it to break in two. But if dynamically precision spin-balanced, a cast or billet steel crankshaft should survive as high as 7,000 RPM for a long time if they've been precision-balanced to the connecting rod and piston assembly using a dynamic balancing machine. Some cast cranks break, and steel crankshafts are prone to breaking, too. When they do break, it's usually due to: being in an engine that broke the connecting rod and the rotating assembly came to a "sudden stop", and the flywheel kept wanting to spin, but cracked the crank instead; an out of balance flywheel (even CNC-machined steel flywheels should be dynamically precision spin-balanced, too); and/or an out of balance starter pulley on the PTO end (which should also be precision-balanced). An out of balanced flywheel or pulley will cause the crankshaft to flex a few thousands of an inch at high RPM. 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 old K-series cranks when precision-balanced. And when a crankshaft breaks at high RPM, it can also break a cast cam or bend a billet steel cam, which could crack the engine block at the cam pin on the flywheel side.


Always Use a Steel Flywheel on a Pulling Tractor Engine That Turns Above 4,000 RPMs!

The smaller (8") steel flywheels require that a billet pulley be installed on the PTO end of the crankshaft and a starter cart w/V-belt be used to crank the engine to start it. (Which can be a major inconvenience if you have no assistance.) And the bigger (9") steel flywheels will accept a ring gear and can be used with a gear starter fastened on the side of the engine block. (Which I think is much more convenient.) Also, the heavier (31 lb.) 9" flywheel is more suitable for stock engines that turn around 4,000 RPMs, and the lighter (19 lb.) 9" steel flywheel is ideal for engines that run at wide open throttle.

Most of the time a heavier-than-stock, custom-made, machined steel flywheel will add more "grunt" or more torque to an engine when pulling. In our experience, a light-weight flywheel will cause an engine to lose power toward the end of a pull. Light-weight flywheels are actually made for high speed racing applications, such as for drag racing or race cars. A lightweight flywheel works great for circle track racing because they allow the engine to accelerate quicker and regain the RPM after coming out of the turns. A heavy flywheel will "bog" an engine down and make it sluggish upon acceleration.

Pulling tractors on the other hand need ground speed (momentum) to do well in a pull, with the use of a heavier-than-stock flywheel. Once a heavy flywheel is spinning, it's hard to stop it or slow it down. A heavy flywheel may somewhat cause a [stock] engine to rev up slower, but once it's revved up, and because of the greater momentum force or increase of weight in the rotating mass, it'll "hold" the RPM longer, allowing a tractor to pull the sled right out the gate.

Remember, there's only two things to be gained by using a heavy steel flywheel; 1: the safety of steel versus cast iron, and 2: the increase in rotating mass with use of a heavier-than-stock flywheel. This means that a heavy flywheel will help an engine to produce more torque at higher RPM, which is very important for a pulling engine. A heavy flywheel (heavier-than-stock) will, without a doubt, will add more lugging power to an engine. That's why they're used on the large farm tractors. By the way - the average 9-1/2" diameter OEM (Original Equipment Manufacturer) cast iron flywheel for the single cylinder K241-K361 Kohler K-series engines with the starter ring gear and full integrated fins (fan blades) weighs 23-24 lbs.

By the way - covering a shiny (new) billet steel flywheel with clear gloss enamel acrylic coating will help identify it visually as made of steel. Otherwise, if it's covered with colored paint, it'll be somewhat difficult to tell right away rather if it's a factory cast iron or steel flywheel. The enamel coating will also help protect the steel flywheel from rusting over time. (I think a nicely painted pulling engine looks good with a shiny [clear coated] steel flywheel.) Actually, the best way to determine if an engine has either a cast iron or steel flywheel (if they look the same) is to tap it with a small hammer or wrench. Cast iron will make a "clunk" sound, and steel will have a high pitch ring to it.

Here's the dimensions if you want to fabricate a 9-1/2" diameter steel flywheel for the K241-K361 single cylinder Kohler engine:

If the above dimensions are somewhat confusing, then perhaps it's best to acquire a Kohler flywheel and take the measurements off of it.

By the way - the flywheels for Kohler K-series and Magnum engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361 will interchange because they all have the same size taper on the crankshaft and in the flywheel, and most of them have two or four threaded holes for driving accessories, and for using an automotive harmonic balancer/vibration damper puller tool to remove the flywheel from the crankshaft. Also, the same flywheel ring gear (gear starter) for Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16, K361, KT17, KT17 series 2, KT19, KT19 series 2, MV16, M18, MV18, M20 and MV20 will interchange. They are all identical.

And adding a heavy pulley on the PTO end of the crankshaft would help add torque to the engine at high RPM. But if/when the engine bogs down upon launch at the starting line or several feet from the starting line, it may be hard to get it to rev back up due to the extra spinning weight. So you gain one thing, but may lose another.


IMPORTANT! NEVER INSTALL A DIRTY FLYWHEEL ON A DIRTY CRANKSHAFT!

Before installing the flywheel on a crankshaft, always clean both tapers by using a a clean cloth (white in color, to see the dirt) to remove any dirt, oil or debris from the crankshaft taper and most importantly, inside the flywheel taper. It's okay to use cleaning solvent (paint thinner) or brake cleaner, because these leave no oily residue when they dry. And use emery cloth to remove any light rust. Clean both tapers thoroughly. This is very important because there must be direct metal-to-metal contact between the two tapers for a secure bonding of the parts. Because the flywheel must keep up with the rapid acceleration (or driving force) of the piston via the crankshaft. Do not use anti-seize for easy removal of the flywheel later! With a heavier steel flywheel (20 lb. and heavier) high strength liquid threadlocker (Red Loctite, Permatex or equivalent) should be applied inside the flywheel taper or on the crankshaft taper to prevent the flywheel from slipping on the crankshaft. Thorough cleaning of the tapers should still be performed even with the use of the threadlocker. If the threadlocker is used, an acetylene torch will be required to soften the threadlocker in order to remove the flywheel. If the flywheel needs to be removed later, use a quality gear puller and an air impact wrench or some muscle. Any oil, dirt or debris trapped in the tapers, or even anti-seize, will, without a doubt, allow the flywheel to slip or rock back and forth on the crankshaft, in which will shear the key, wallow out both keyways and possibly crack or break the flywheel and/or crankshaft. Dirt/oil on the tapers is the main reason why most custom-made billet steel high-performance crankshafts break. And if the flywheel use a Cub Cadet or billet aluminum clutch hub adapter, be sure to install the [1-3/8" o.d.] thick flat washer under the retaining nut or bolt and then torque the nut or bolt to the proper specs.

NOTE: As long as the rotating clutch components are trued-up in a metal lathe to minimize vibrations, and the wide, thick washer is used inside the hub to secure the hub to the flywheel, and the flywheel retaining nut or bolt properly torqued, the OEM (Original Equipment Manufacturer) cast aluminum clutch hub have been proven to hold up to a wide open throttle pulling engine.


The Best Way to Torque the Flywheel Retaining Bolt or Nut - Top of Page

Personally, I use an air impact wrench to lightly snug the flywheel nut or bolt against the flywheel, then I finish torquing it with a torque wrench. The flywheel won't rotate with an air impact wrench. If an air impact wrench isn't available, and if the flywheel has a starter ring gear, clamp Vise Grips on the edge of the ring gear, allow it to bump against the bolt boss on the bearing plate and then the flywheel nut or bolt can be loosened to be removed, or when installing, torqued to specs. But if the flywheel doesn't have a ring gear, clamp the Vise Grips on the PTO end of the crankshaft, install a long bolt in one of the bolt holes on the PTO end of the block, and allow the Vise Grips to bump against the bolt to loosen or torque the flywheel nut or bolt. As easy and simple as this may be, do not place a steel bar through the fins of the flywheel to loosen or torque the bolt or nut! Being the fins are made of brittle cast iron, doing this could cause a fin to break off. If a fin breaks off, this will cause the flywheel to be dangerously out of balance, and the engine will vibrate badly.

With the tapers clean, and when the flywheel nut or bolt is tightened or torqued to specs, the "squeezing" action of the flywheel taper actually "grips" it to the crankshaft, guaranteeing positive metal to metal contact, with no slip whatsoever. Torque the 15/16" nut at 65 ft. lb., and the 3/8" bolt at 40 ft. lb., but do not overtorque it! (As with an air impact wrench.) And Kohler's flywheel [castle] nut is self tightening. Therefore, a lock washer isn't necessary. But sometimes the nut will wear and tend to loosen over time. When this happens, the flywheel could loosen, and the keyway in both the flywheel and crankshaft will become damaged beyond repair. Therefore, a new all metal self locking nut is required for a professional repair. But use a split lock washer on the bolt. And use a grade 8 bolt, nothing less.


IMPORTANT! A cast iron flywheel with a crack in it, even a small crack, should never be used on any engine!

Oil, grease, dirt on the crankshaft and/or flywheel tapers or even an overtorqued nut or bolt could cause the center in a cast iron flywheel to crack in the keyway or the threaded stud of the crankshaft to break off. Cast iron flywheels always crack at the weakest point, which is at the keyway. If the crack is welded, and when the flywheel is installed on the crankshaft, and the nut or bolt is torqued to specs, the taper would still split next to the weld. But steel flywheels don't crack (or break).

A crack in a flywheel will cause an engine to vibrate severely, plus it'll be noisy. (It'll make a "clunk, clunk" sound at idle.) The crack will get worse over time, causing the flywheel to split in half at high RPM. If this happens, the two halves could cause severe bodily injury or possibly death if they were to become airborne and strike an innocent bystander.

The only valuable part on a cast iron flywheel with a crack in the keyway would be the starter ring gear. It can be installed on a [good] cast flywheel or a steel flywheel. Cast iron flywheels that's in good condition works great up to 4,000 RPM. (The factory setting of maximum RPM for virtually all small gas engines, including all of Kohler engines is 3,600.) Above 4,000 RPM, a steel flywheel is highly recommended for safety.

To minimize damage to the keyways, do not use a steel flywheel key. A heat-treated hardened key would be even a worse thing to use. An soft aluminum (4041 hardness) key works best. To keep a keyway in a cast flywheel from splitting, it's best to use soft aluminum key. The reason for this is if the connecting rod breaks resulting in instant crankshaft lockup, the soft key will prevent damage to the flywheel and crankshaft. The aluminum key will shear in two, allowing the flywheel to slip on the crankshaft, preventing damage to either the flywheel or crankshaft. A steel key will cause a cast iron flywheel to crack or break, or if a flywheel loosens on the crankshaft, it'll wallow out the keyways. But if an aluminum V-belt starter pulley with ignition timing degree marks is installed on the PTO end of the crankshaft, there's really no need to install a flywheel key. The only reason most small engines use a flywheel key is to time the ignition, and not to prevent the flywheel from slipping on the crankshaft.


Removing the Majority of the Integrated Fins from the Flywheel to Reduce Drag on Engine and Boost Horsepower -

One sure way to increase the power output of a 4,000 RPM stock pulling engine is to reduce the amount of [air] drag that the flywheel fins cause. To do this, the majority (about 3/4) of the fins will need to be removed from the flywheel. For competition pulling, the flywheel will still provide plenty of fresh air to sufficiently cool the engine. This shouldn't be done for an engine that's used for heavy towing, pushing snow or general lawn and garden use because the engine could run hotter than normal, causing premature wear.

How to Remove the Integrated Fins -

A heavy duty 14" electric chop saw with a metal cut-off wheel, like the one that most automotive muffler shops use, can be used to remove the majority of the fins from the flywheel. To cut the flywheel fins off using a heavy duty electric chop saw with a metal cut-off wheel...

  1. First of all, wear eye protection or safety glasses and a dust and particle mask or surgical face mask to keep from breathing in the cast iron and cutting wheel dust particles. (If you don't wear a mask, you may wish you did.)
  2. Position the flywheel in alignment with the cutting wheel, firmly hold the flywheel with one hand and carefully bring the cutting wheel down even with the outside taper in the flywheel. Cut a few fins, then rotate the flywheel, and keep doing this until all the fins are removed. Try to keep all the fins even and in alignment, too.
  3. Now chuck the flywheel in a large metal lathe to true up the fins so they'll all be the same height. (This require less effort to rebalance.) If one has access to a large CNC machine, this would work better, the fins would all be the same height and the cutting process would be much safer.
  4. To spin-balance the flywheel, a 1-1/2" diameter x approximately 24 mild steel rod machined with a precision-machined taper to match the angle of the taper in the flywheel, and a threaded bolt hole in the end to retain the flywheel will need to be fabricated for chucking the flywheel in the metal lathe. This shaft is also used to spin-balance the flywheel afterwards.

IMPORTANT! Due to the brittle material, a cast iron flywheel (altered or unaltered) shouldn't be used on an engine that runs at high RPM or at wide open throttle. Due to the combination of severe centrifugal force and engine vibration, the flywheel could explode, causing serious injury or possible death to a bystander. The Kohler Magnum plastic flywheel fan shouldn't be ran above 4,000 RPM either, because it can explode, too.

Then without a doubt (and using common sense), any flywheel with the majority of the fins removed should definitely be dynamically precision spin-balanced with an automotive crankshaft/flywheel balancing machine. The same machine for balancing the crankshaft to the connecting rod/piston assembly can be used to balance flywheels, too. The flywheel should be balanced to within 1/10th of an ounce (0.1 lb.) or 1 gram. For an example of how much 1/10th of an ounce is, a dime (10¢) weighs exactly 1/10th of an ounce (or 2 grams).

NEVER use an automotive tire bubble balancer to balance a flywheel! Also, make sure the flywheel has all the internal magnets intact (for the charging system) or remove the magnets altogether if using no charging system. And do not spin a cast flywheel (on the engine) no faster than 4,000 RPM! Or better yet, install a billet steel flywheel and an electric fan to cool the engine.


IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT!
Below are the results of a cast iron OEM Kohler flywheel with a crack in the keyway, a broken-off fin, and/or when spun well above 4,000 RPM (wide open throttle) Ê

The photos below are the results of a 9-1/2" diameter cast iron Kohler flywheel when it was spun at wide open throttle in a garden pulling tractor. This was a very serious accident that could have been a life-threatening tragedy. Remember: a well-constructed and precision-balanced steel flywheel is cheap compared to hospital bills, rehabilitation or funeral costs and not to mention the seemingly never-ending lawsuits!

The guy (name withheld) had just recently bought the Pro Stock motor. He already had the clutch setup on the flathead Kohler twin he was running. According to what a friend of his told me (that also has a Pro tractor) the guy called him and asked would it be ok just to start the motor so he could hear it run. He was told not to turn it over 3,000 RPM. There is no question the guy knew he needed a steel flywheel and safety shields on the tractor before pulling it. I am confident those measures would have been on it before he pulled it the first time. There "was" someone standing by the tractor - the guy that owns it. He was working the throttle standing right in-line with the cast iron flywheel. You can see what it did to the air filter. Apparently it hit the carburetor and filter on its way to hitting him. It wasn't his leg that got the brunt of the piece of flywheel!

He just got too eager to find out what he had purchased and made a bad decision. It's an injury that will be with him the rest of his life. The point of putting these pictures on this site is so other pullers would not make the same mistake. I'm confident he is embarrassed by his actions...but he didn't have to share those pictures, ya know. I admire him for sharing these photos, and he's still suffering from the accident. - Story by Ron Ethridge

Also, check out this video: Farmall 1206 Breaks in Half when flywheel Explodes - YouTube (https://www.youtube.com/watch?v=y7gKbk0jyyM).

IMPORTANT! It's highly recommended that all flywheels, despite the material it's made of, be dynamically precision spin-balanced with an automotive crankshaft/flywheel balancing machine. The same machine to balance a crankshaft can be used to balance a flywheel, too. And never use an automotive tire balancer or "bubble balancer" to balance a flywheel! They are NOT precision enough for a flywheel!

Advertisement:
If you need the products listed below Ê, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell). 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.) A-1 Miller's shop is open to the public from 9am to 5pm, including weekends (except Holidays). Please call before coming so I'll be here waiting for your arrival. Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Please click here to place an order.
High Quality Inductive Handheld Small Engine Wireless Tachometer. For gas/spark ignite engines only. Very accurate. This handheld analog tach works great for checking/setting the RPM on various small engines in the shop, and/or for checking/setting the RPM [tech] on stock governored engines at pulling events, ATVs/UTVS, etc. Hold sensor (antenna) close to spark plug wire for reading. Operates off a self-contained replaceable 9 volt battery. Has built-in battery voltage check. Reads up to 5,000 RPM on the low scale, and 15,000 RPM on the high scale.
  • $85.00 each, plus shipping & handling.
High Quality Inductive Small Engine Tachometer and Hour Meter. High quality and very accurate. Large 3/8 inch LCD display. Works with all spark ignition engines by selecting engine type using S1 and S2 buttons. Instructions included. Tachometer reads up to 99,999 RPM. Hour meter reads up to 9999:59 hours/minutes then resets to Zero. Programmable maintenance hour setting with service icon, a reminder when to change oil or other service. Can be manually reset to Zero hours. Programmable maintenance hour setting with service icon, a reminder when to change oil or other service. Easy installation: Single wire wraps around spark plug wire and secured with two supplied nylon zip-ties. No wire terminal connections required. Tachometer can be surface-mounted and secured with two screws. Has built-in battery rated up to 4 years. Sealed unit; weather and water resistant. Dimensions: 2" wide x 1-3/4" depth x 3/4" height.
  • $20.00 each, plus shipping & handling.
High Quality Digital Tachometer/Proximity Sensor Kits. Will work with small engines or automotive engines, gas or diesel. This precision digital tachometer is triggered by the same method as crank trigger ignition with a proximity sensor to detect a target, which can be a small ferrous steel screw or pin, or magnet in a rotating disc or on/in flywheel. A sturdy steel or aluminum bracket will need to be fabricated by customer to mount the sensor in close proximity of the detector/trigger target. Set air gap/clearance at .010"-.188". Tachometer can be dash- or panel-mounted. Tachometer works with 8-24 volts DC, proximity sensors works with 6-36 volts DC. Tachometer can be dash- or panel-mounted. Tachometer works with 8-24 volts DC, proximity sensors works with 6-36 volts DC. Dimensions of each proximity sensor below: 15/32" (12mm) diameter x 1-3/8" thread length. Some proximity sensors have an LED (Light Emitting Diode) on the rear of unit. If the proximity sensor is wired incorrectly, the LED will stay on and go off when activated. Displays up to 9,999 RPM. Very accurate. Tachometer returns to zero [0000] when power is turned off. Wiring Instructions: #1 wire on tachometer connects to brown wire on (either) proximity sensor and ignition switch (battery positive (+) post), #2 wire on tachometer connects to blue wire on (either) proximity sensor and engine/chassis ground (battery negative (–) post), and #5 wire on tachometer connects to black wire on (either) proximity sensor. Wires #3 and #4 connects to nothing. Wiring can also be integrated with crank trigger ignition with a proximity sensor. Choice of RED or BLUE numeric display.
  • Tachometer only. To be used with a 3-wire hall effect, inductive or cube-shaped proximity sensor. $12.00 each, plus shipping & handling.
  • Complete Kit with Hall Effect Proximity Sensor. $22.00 each, plus shipping & handling.
  • Complete Kit with Inductive Proximity Sensor. $25.00 each, plus shipping & handling. Return to previous section.


Shielding of the Flywheel is Important!

I remember years ago, I was reading a club's rules, and it stated that all tractors must have a steel flywheel, and it must be shielded 360º with minimum 1/4" thick steel. I asked one of the pullers of the club, "why shield a steel flywheel? It's not going to break." And he told me: "There's a possibility that the end of the crankshaft could break off."

Actually, it's not rare that this kind of thing happens. It's happened to various pullers. The end of a crankshaft, despite if it's steel or cast iron, can break off next to the flywheel. It's a slight possibility. But then again, it could happen. Like the old saying goes: "A bad apple will spoil the bunch." And remember Murphy's Law? Must be prepared for the unexpected. So need to shield them flywheels folks, before a catastrophe happens.


Advertisement:
If you need any of the parts or services listed below Ê, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell). 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.) A-1 Miller's shop is open to the public from 9am to 5pm, including weekends (except Holidays). Please call before coming so I'll be here waiting for your arrival. Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. Please click here to place an order.
8" diameter OEM Kohler flywheel for engine models K241-K361. Used and in excellent condition. With full fins. Use with starter/generator for general lawn and garden use. This flywheel is for battery ignition only, not magneto or solid state ignition, but can be used with my PerTronix Ignitor crank trigger ignition system. In excellent condition and unaltered. No crack in the keyway, no broken or missing fins. This flywheel is for stock engines only; not to be turned above 4,000 RPM! Discontinued from Kohler. OEM Kohler part # 47 755 02-S.
  • $50.00 each, plus shipping and handling. (When available.)


9-1/2" diameter OEM Kohler flywheel for engine models K241-K361. Used and in excellent condition. With full fins, with internal charging magnets for 5-1/2" o.d. stator. For general lawn and garden use. Has narrow edge. This flywheel is for points/condenser ignition only, not Breakerless, magneto, solid state ignition or crank trigger ignition. In excellent condition and unaltered. No crack in the keyway, no broken or missing fins. This flywheel is for stock engines only; not to be turned above 4,000 RPM! Discontinued from Kohler. OEM Kohler part #'s 47 025 22-S or 47 025 24-S.

  • Flywheel without ring gear. Customer installs own ring gear. $50.00 each, plus shipping and handling. (When available.)
  • Flywheel with ring gear. $70.00 each, plus shipping and handling. (When available.)


9-1/2" diameter OEM Kohler flywheel for engine models K241-K361. Used and in excellent condition. With ring gear and with internal charging magnets for 5-1/2" o.d. stator. For general lawn and garden use. Has 3/4" wide edge. This flywheel is for battery ignition, not Breakerless, magneto or solid state ignition, but can be used with my crank trigger ignition system. In excellent condition and unaltered. No crack in the keyway, no broken or missing fins. This flywheel is for stock engines only; not to be turned above 4,000 RPM! Discontinued from Kohler. OEM Kohler part #'s 47 025 22-S or 47 025 24-S.

  • Flywheel without ring gear. Customer installs own ring gear. $75.00 each, plus shipping and handling. (When available.)
  • Flywheel with ring gear. $100.00 each, plus shipping and handling. (When available.)


9-1/2" diameter OEM Kohler flywheel for engine models K241-K361. Used and in excellent condition. With full fins, ring gear and internal charging magnets for 5-1/2" o.d. stator. Has projection (hump) for BreakerLess Ignition or crank trigger ignition. For general lawn and garden use. This flywheel is for battery- or Breakerless-ignition, not magneto or solid state ignition, but can be used with my crank trigger ignition system. In excellent condition and unaltered. No crack in the keyway, no broken or missing fins. This flywheel is for stock engines only; not to be turned above 4,000 RPM! Discontinued from Kohler. OEM Kohler part # 47 025 28-S.

  • Flywheel without ring gear. Customer installs own ring gear. $100.00 each, plus shipping and handling. (When available.)
  • Flywheel with ring gear. $125.00 each, plus shipping and handling. (When available.)


9-1/2" diameter OEM Kohler flywheel for engine models K241-K361. Majority of fins removed, dynamically precision spin-balanced with an automotive crankshaft/flywheel balancing machine. Without internal charging magnets. This flywheel is recommended for stock competition pulling engines only; not to be turned above 4,000 RPM! Click picture to the right for a larger view.

  • Flywheel without ring gear. Customer installs own ring gear. $135.00 each, plus shipping and handling. (When available.)
  • Flywheel with ring gear. $160.00 each, plus shipping and handling. (When available.)


Used ring gear for 9-1/2" diameter OEM Kohler or steel flywheel. $25.00 each, plus shipping & handling. (When available.)


Your OEM Kohler flywheel - Remove majority of fins and precision spin-balance. Includes remove most of the integrated fins, chuck it in our metal lathe to true up the fins so they're all even and then precision spin-balance it. Recommended for stock competition pulling engines only; not to be turned above 4,000 RPM! $85.00 labor, return shipping extra.

Internal Flywheel Magnets for Alternator Charging System. Fits aluminum and cast iron block single and twin cylinder Kohler engine models K141, K161, K181, K241, K301, K321, K341, K361, KT17/KT17 series 2, KT19/KT19 series 2, KT21, M8-M16, MV16, M18, MV18, M20, MV20, K482, K532, K582, CH1000, CH11-CH26, CH430, CH450, CH620-CH682, CH730-CH752, CH940, CH980, CV1000, CV11-CV25, CV430-CV493, CV620-CV682, CV725, CV730-CV940, CV960, CV980, ECV630-ECV680, ECV730-ECV749, ECV630-ECV680, ECV730-ECV749, ECV850-ECV880, ECV940, ECV980, FCV740, KT610, KT620, KT715-KT745, LH430, LH640-LH690, LH750, LH755, LV625-LV680, PCH680, PCH740, PCV680, PCV740, PCV850, PCV860, SV470-SV480, SV530-SV590, SV600-SV620, SV710-SV740, SV810-SV840, TH16, TH18, TH575, ZT710-ZT740, except certain early John Deere with a single cylinder Kohler engine with the 4-1/4"± charging stator, and larger Tecumseh engines with an alternator charging system having the 5-1/2" diameter stator. Magnet(s) may come in 3/4" or 7/8" height, but will work the same. Comes with North-South poles identified. Not available separate from Kohler. Used and in excellent condition.
  • $10.00 each, plus shipping & handling. (When available.)
  • $50.00 per set of 6 magnets, plus shipping & handling. (When available.)
Reconditioned OEM Kohler Crankshafts - [When available.]

Available for Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16 and K361. 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 PTO shaft w/1/4" wide keyway. 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'll probably have a better 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 have the engine's original model and specification numbers, go to kohlerplus.com (require Internet Explorer), to find the correct part number for the crankshaft, then find the dimensions and specifications of the crankshaft is here: CRANKSHAFT REFERENCE MANUAL. (require Adobe Acrobat Reader and use Google Chrome web browser for a faster download of web sites with large files.) Shipping weight: 12 lbs.

  • Crankshafts for Kohler engine models K241/M10. $100.00 each, plus shipping & handling. (When available.)
  • Crankshafts for Kohler engine models K301/M12. $125.00 each, plus shipping & handling. (When available.)
  • Crankshafts for Kohler engine models K321/M14, K341/M16 and K361. $150.00 each, plus shipping & handling. (When available.)
  • NOTE: Once installed and in use, there is no warranty or guarantee of any kind on any crankshaft purchase!

Dynamic Precision Spin-Balancing Service -

Balance (cast or steel) flywheel for Kohler K241-K361 cast iron block engines. $60.00 each labor, plus return shipping and handling.

Balance cast iron (Kohler) crankshaft and matching connecting rod and piston assembly. $200.00 per rotating assembly, plus return shipping & handling. NOTE: I will need to take your parts to the only reputable and trusted automotive machine shop in Jefferson City, Missouri that does professional engine balancing. Or you can contact Precision Machine, Inc. (PMI) to have your rotating assembly dynamically precision spin-balanced. They are located at 1703 Christy Drive, Jefferson City, MO 65101. Phone: 573-635-7214. Return To Previous Paragraph or Section

  • Regrind Crankshaft Journal - $50.00 per journal. On a twin cylinder crankshaft, $100.00 total, plus return shipping & handling. Note: The K241-K361 Kohler crankshafts can be ground as far as .030" and still be safe to use with a matching undersized bearing insert installed in the 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.
  • On the Kohler engine models K141, K160/K161 or K181/M8 and other makes and models of engines, if the crankshaft is worn beyond .010" and needs to be reground again, the journal can be reground to .020" and then the connecting rod can be resized so it'll fit the smaller undersize journal. I do this sometimes on engines when a .020" undersize rod isn't available. This hurts nothing and it lasts as long as an ordinary STD rod and crank journal. Price for doing this is $75.00, plus return shipping & handling. I will need your crankshaft and connecting rod.
  • Repair a broken off stud in crankshaft on flywheel end: $20.00. 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. And a steel bolt is much stronger than a cast iron stud. Because cast iron is brittle and steel is flexible.
  • Drill and cut 7/16-30 UNF threads in the PTO end of the crankshaft for a retaining washer and bolt. $20.00.
Flywheel Retaining NutFlywheel Retaining Nuts for threaded stud on end of K-series and steel crankshafts. IMPORTANT: Apply thin coat of motor oil on threads of crankshaft before installing nut then torque each at 65 ft. lbs.
  • Plain Nut. 5/8-18 UNF threads. Apply medium strength liquid threadlocker on threads to prevent flywheel from possibly loosening. Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.00 each, plus shipping & handling.
  • OEM-Type Castle/Tapered Seat Self-Locking Nut. 5/8" diameter, fine thread (5/8-18 UNF). A-1 Miller part. Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling.
  • All-Metal Self-Locking Nut. 5/8" diameter, fine thread (5/8-18 UNF). Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling.
  • Plain Nut. 3/4-16 UNF threads. Apply medium strength liquid threadlocker on threads to prevent flywheel from possibly loosening. Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.00 each, plus shipping & handling.
  • OEM-Type Castle/Tapered Seat Self-Locking Nut. 3/4" diameter, fine thread (3/4-16 UNF). A-1 Miller part. Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling.
  • All-Metal Self-Locking Nut. 3/4" diameter, fine thread (3/4-16 UNF). Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling.
Flywheel Retaining Bolt and Washer Kit for threaded hole in end of newer K-series and all Magnum crankshafts. Bolt: 3/8-24 UNF threads, grade 8 material w/split lock washer. Washer: 3/16"± thickness x 1-1/4" diameter. Torque bolt to 40 ft. lb. IMPORTANT: For proper torque and before installing, apply thin coat of oil on threads of bolt or inside threaded hole.
  • All high quality A-1 Miller aftermarket parts. $4.00 per kit, plus shipping & handling.
  • All OEM Kohler part #'s 25 086 24-S (bolt; $2.22), 12 468 03-S (thick washer; $3.69). $5.91 per kit, plus shipping & handling.
Flat washer for retaining flywheel or aluminum clutch hub to flywheelFlywheel / Aluminum Hub Retaining Washers. A thick, wide washer is a must to secure flywheel and prevent clutch/driveshaft aluminum hub adapter breakage! Each made of steel and measures 3/16"± thickness x 1-1/4" diameter.
  • Washer w/13/32" hole. To be used with aluminum hub with 3/8" hole.
    • A-1 Miller part. $3.00 each, plus shipping & handling.
    • OEM Kohler part # 12 468 03-S. $3.40 each, plus shipping & handling.
  • Washer w/5/8" hole. To be used with aluminum hub with 5/8" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-104. $3.50 each, plus shipping & handling.
  • Washer w/3/4" hole. To be used with aluminum hub with 3/4" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-71. $3.50 each, plus shipping & handling.
Steel Adapter Step-Washer for installing Cub Cadet cast 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! NOTE: As long as the rotating clutch components are trued-up in a metal lathe to minimize vibration, and the wide, thick washer is used inside the hub to secure the hub to the flywheel, and the flywheel retaining nut or bolt properly torqued, the OEM cast aluminum clutch hub have been proven to hold up to a wide open throttle pulling engine.
  • $12.00 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" length. OEM Kohler part # X-366-1-S.
  • Used. $1.00 each, plus shipping & handling. (When available.)
  • New. $2.50 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" length. 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" length.
  • High quality aftermarket. $1.00 each, plus shipping & handling.
  • OEM Kohler part # X-286-17-S. $1.70 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" length. Replaces Kohler part # X-286-17-S.
  • $5.00 each, plus shipping & handling.


Steel Woodruff (Semicircular) Flywheel Key for early Kohler engine models K160, K161, K181 and later K241/M10-K341/M16 and K361 K-series and all Magnum engines. 3/16" wide x 1" length.
  • High quality aftermarket. $1.00 each, plus shipping & handling.
  • OEM Kohler part # X-46-3-S. $1.85 each, plus shipping & handling.


Steel Woodruff (Semicircular) Flywheel Key for most OHV aluminum block Kohler engines. 3/16" wide x 5/8" length.
  • High quality aftermarket. $1.00 each, plus shipping & handling.
  • OEM Kohler part # X-42-15-S. $1.60 each, plus shipping & handling.
Flat washer for retaining flywheel or aluminum clutch hub to flywheelFlywheel / Aluminum Hub Retaining Washers. A thick, wide washer is a must to secure flywheel and prevent clutch/driveshaft aluminum hub adapter breakage! Each made of steel and measures 1-1/4" o.d. x approximately 1/4" thick.
  • Washer w/13/32" hole. Must be used with aluminum hub that has a 3/8" hole.
    • A-1 Miller part. $3.00 each, plus shipping & handling.
    • OEM Kohler part # 12 468 03-S. $3.40 each, plus shipping & handling.
  • Washer w/5/8" hole. To be used with aluminum hub that has a 5/8" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-104. $3.50 each, plus shipping & handling.
  • Washer w/3/4" hole. To be used with aluminum hub that has a 3/4" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-71. $3.50 each, plus shipping & handling.
Steel Adapter Step-Washer for installing Cub Cadet cast 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! NOTE: As long as the rotating clutch components are trued-up in a metal lathe to minimize vibrations, and the wide, thick washer is used inside the hub to secure the hub to the flywheel, and the flywheel retaining nut or bolt properly torqued, the OEM cast aluminum clutch hub is capable of holding up to a wide open throttle pulling engine.
  • $12.00 each, plus shipping & handling.
1/4" Steel Dowel Pin for aluminum clutch hub. 3/4. Secures above hub to flywheel to prevent slippage.
  • $1.00 each, plus shipping.
Flywheel grass/safety steel screen for use in IH-built Cub Cadet garden tractors with Kohler engine models K161 and K181. 5-9/16" diameter.
  • New Old Stock or Used and in excellent condition. Discontinued from Kohler. OEM Kohler part # 231819-S. $20.00 each, plus shipping & handling.
Flywheel grass/safety steel screen for use in IH-built Cub Cadet garden tractors with Kohler engine models K241 and K301. 7" diameter.
  • Used and in excellent condition. $120.00 each, plus shipping & handling.
  • New. OEM Cub Cadet part # KH-235190 and OEM Kohler part # 235190-S. $240.00 each, plus shipping & handling.


Cooling a Pulling Engine with an Electric Fan (so the engine will last longer) - (Updated 8/2/17) Top of Page

Using a steel flywheel with no cooling fins will, without a doubt, allow any engine to operate at a much higher temperature. If you're burning methanol fuel and full synthetic motor oil, they'll help keep the engine somewhat cool, but the combustion chamber will still run extremely hot from lack of a cooling system. Excessive heat will cause an engine to lose power and eventually "wear out." Therefore, installing an electric fan to cool the engine wouldn't be a bad idea. Pulling tractors that have a smaller engine (8hp or 10hp) usually don't go very fast down the track will really benefit from an electric cooling fan.

The most popular, compact, low amp draw, and high velocity 12 volt cooling fans that works great for a single- or twin-cylinder pulling engine is the Attwood Turbo Blower (model 3000; 3" or 4000; 4") or Rule In-Line Blower (model 140; 3" or 240; 4"). These [plastic body] fans should be mounted securely with rubber bushings to prevent the housing from breaking due to normal single cylinder engine vibrations at wide open throttle. Certain automotive shock absorber rubber bushings or heavy duty rubber grommets will work to mount these fans. These fans are available on eBay and most businesses that deal with boats or boating accessories, parts and equipment. Another type of low amp draw and high velocity fan that works great for a pulling tractor that do not require rubber isolator mounting bushings is a 12 volt ATV (All Terrain Vehicle) engine cooling fan. These fans are available in 6" and 10" diameter, are very durable and is able to withstand high vibrations because they fasten using four [reinforced] mounting points versus the Attwood and Rule fans, which only use two mounting points. These fans are available on eBay and most businesses that deal with ATVs or ATV accessories, parts and equipment.

Any cooling fan should be mounted between the grille and PTO end of the engine (in a Cub Cadet), and aimed toward the exhaust area of the combustion chamber, because that's the hottest part of any engine. And due to high speed vibrations from the engine, the fan shouldn't be used to cool the engine while pulling. The vibration could also damage the tiny and delicate brush holders in the fan motor, which could render the fan useless. The fan should only be used for cooling with the engine off just before a pull-off, between classes when there isn't enough time for the engine to naturally air-cool, or idling back to the pit area just after a pull.

Because an electric fan draws power from the battery, which could weaken the spark for the ignition system, always use a high quality lawn and garden battery with a minimum of 350 cold cranking amps, or better yet, use an automotive battery. Any 12 volt DC fan with two wires and not a grounded body are reversible. So make sure the wires are connected correctly so the fan will blow air toward the engine, and not the other way. Return to a previous page or paragraph.


The same flywheel ring gear (gear starter) for Kohler engine models K241/M10, K301/M12, K321/M14, K341/M16, K361, KT17, KT17 series 2, KT19, KT19 series 2, MV16, M18, MV18, M20 and MV20 will interchange. They are all identical. To swap a starter ring gear from one flywheel to another, first of all, Kohler don't sell just the ring gear by itself. You will need to acquire a used flywheel with a good ring gear on it.

  1. To remove the ring gear from a flywheel, it's not necessary to heat it. Instead, place the flywheel with the fins facing up on a steel top work table, bench or concrete floor, then use a brass drift and 2-3 lb. hammer to remove the ring gear. Gently tap equally around the entire circumference of the gear to avoid distorting or bending it. It should eventually fall off.
  2. To install the ring gear on a flywheel, position the flywheel with the fins facing down on a fire-proof steel top work table, bench or concrete floor, and place the ring gear on the flywheel with the beveled edge of the gear teeth facing upward. (This allows the starter gear teeth to engage more easily without causing damage or wear to the teeth.)
  3. Use an oxy-acetylene torch to heat the ring gear 360º to expand the steel so it'll install on the flywheel. This should only take a few minutes. Once the gear drops in place, it'll have a loose fit until it cools. Allow it to air-cool. Do not cool it with water. Once cooled, it'll have a tight, secure fit. NEVER attempt to install a [cold] ring gear onto the flywheel with a hammer! Doing this will bend it badly out of shape and ruin it for use.
  4. Click here to watch a video of this process: How to swap or flip a ring gear off a flywheel - YouTube (https://www.youtube.com/watch?v=cDGdJ0yKbG8).


How to Widen the Frame Rails on a Narrow Frame Cub Cadet for Use of a Large Flywheel with a Gear Starter - (This is much easier to do on a platform work table.)

On a garden pulling tractor, it's best to use a gear starter with the larger diameter flywheel, because a starter/generator will rob the engine of valuable horsepower, which needs to be put through the rear tires. It'll be better to spin the tires than the starter/generator. As an added bonus, the bigger (heavy, steel) flywheel will add horsepower and torque to the engine at high RPMs.

The larger 9-1/2" diameter flywheel with a starter ring gear, larger K-series bearing plate and K-series flywheel housing can be installed on any K241-K361 Kohler engine for use with the gear starter, as long as there's an indention in the block just above the starter motor's mounting holes (when using the upper-mount type starter). (The small flywheel is 8" in diameter.) If the engine is being installed in a narrow frame Cub Cadet (models 70, 71, 72, 73, 100, 102, 104, 106, 122, 124 and 126), the frame rails must be widened to accept the larger flywheel, bearing plate and flywheel housing. No charging system is required or recommended for a pulling tractor because it'll rob horsepower and add unnecessary weight and extra wiring. Read below for information on how to convert a narrow frame Cub Cadet.

If you want to do away with the old, heavy, battery draining, power-robbing starter/generator on a narrow frame Cub Cadet and install a lightweight gear starter along with the larger 9-1/2" diameter geared flywheel on a Kohler engine, you'll have to widen the frame rails. To do this, with the engine removed, cut a slot halfway down into the frame where the front of the flywheel shroud sits. For the rear cut, measure 17" back from the front of the frame (to where the metal bends for the clutch cover), and then make the cut there. Then using a large pipe wrench or very large Crescent wrench (I found either of these work great), bend or spread the frame rails outward 11" from the front of the frame. Use a (large) flywheel shroud as a gauge to determine how wide the rails will need to be. This will eliminate having to put the engine in and take it out again. Spread the frame 5" forward (towards front of tractor) from where the slot was cut. Check to see that the frame rails are bent upward from spreading out the metal. (Hold a straight edge tool under each frame rail to check for straightness.) If the widening process was performed correctly, then they shouldn't be bent. If they are bent, they will need to be straightened so the driveshaft/clutch will be in correct alignment with the engine. It'll be best to securely weld two full-length 1/4" thick x 1-1/2" wide steel pieces under each frame rail to reduce the chance of bending. Then securely weld a 1/8" thickness mild steel gusset plate (angle reinforcement brace) into each wedge/cut) opening. A Magnum flywheel housing and bearing plate would require a lot more widening of the frame rails to install in a narrow frame Cub Cadet.

Widening the frame rails as mentioned above and then properly welding in the gussets (reinforcement angle braces) shouldn't weaken it. But make sure that the frame is in fact straight before welding in the gussets. Because sometimes it can bend during the process of widening the frame. To prevent the frame from bending overtime when doing ground-pounding wheelies, weld in the gussets on both the inside and outside of the frame. Put down a good bead of weld, too. If the frame is bent, only slightly, this will interfere with the operation and proper alignment of the clutch and driveshaft. The Cub Cadet model 147 is the only narrow frame tractor that came from the factory with widened places in the frame for the large flywheel. This is also the last narrow frame Cub Cadet manufactured before the wide frame models were produced. There's no need to widen the frame rails on a wide frame Cub Cadet (models 86, 108, 128, 800, 1000 and 1200), because the large flywheel and gear starter will clear the rails.

The parts needed to convert a K241-K341 Kohler K-series engine with a starter/generator into a gear starter are as follows:

To install a gear starter on a K241-K341 Kohler engine in a narrow frame Cub Cadet...

  1. The engine will need to be removed.
  2. The frame rails will need to be cut and widened (enough to clear the [9-1/2"] flywheel shroud), and a couple of gusset plates will need to be welded in for strength.
  3. Install the large diameter bearing plate, (9-1/2") flywheel with a starter ring gear and flywheel shroud on the engine.
  4. A gear starter motor will need to be bolted on the side of the engine block. The block will need to have an indention for the starter.
  5. Then there's the wiring, starter solenoid and push-button starter switch that needs to be installed.

But if you prefer to use the starter/generator when pulling, remember this: the generator part require less than 1hp of engine power to charge a fully drained battery. Therefore, if you were to install an OFF/ON toggle switch to turn off the field windings in the starter/generator, this will prevent it from charging the battery. Which will allow the engine to produce more power.

After installing the flywheel shroud and if the hub adapter, flywheel or starter cup screen rubs part of the shroud on one side. This means the big hole in the shroud is out-of-alignment with the centerline of the crankshaft. It needs to be tweaked to put it in alignment. Sometimes I have the same problem with my customer's engines. To fix it, install all the mounting bolts in the shroud, but leave them loose, then place a soft 2x4 board against the shroud, and then hit the board with a big hammer or heavy rubber hammer to force the shroud over until it's centered with the screen. This is the only way I know how to fix it. I don't know how they get out of alignment in the first place, unless it came that way from the factory and haven't been noticed before. Heck, when rebuilding and/or reassembling an engine, you tend to notice a lot of new things about it. It's kind of like painting your own house on the outside. The owner don't notice maybe a cracked window, loose siding, etc., until they get up-close with it.

Installing a 10-16hp Single Cylinder Kohler Magnum Engine in an Older Cub Cadet Garden Tractor -

With the flanges on a Kohler Magnum engine model M10, M12, M14 or M16 block cut off and with a narrow Cub Cadet oil pan installed, the Magnum will install in a spread-frame Cub Cadet with little to no modifications. But it won't fit in a narrow- or wide-frame Cub Cadet, because the Magnum flywheel shroud and bearing plate are too wide to fit between the frame rails, even when the frame rails on a narrow frame Cub Cadet are widened. Therefore, a large flywheel shroud, bearing plate and upper mount gear starter from an older K241-K341 Kohler K-series engine will need to be installed on the Magnum engine and then the Magnum should install in a narrow- or wide-frame Cub Cadet with little to no modifications.


Advertisement:
If you wish to have your Kohler stock or pulling engine tested on a dynamometer (dyno), please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell). 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.) A-1 Miller's shop is open to the public from 9am to 5pm, including weekends (except Holidays). Please call before coming so I'll be here waiting for your arrival. Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest.

A-1 Miller's Fully Computerized Stuska Water Brake Engine Dynamometer (Dyno) Service!

For performance testing engines up to 200hp at speeds up to 12,000 RPM. The only engine dyno service in Missouri for Kohler pulling engines! Now set up and fully operational, customers can rent dyno time, fine tune and make adjustments or changes to their engines for maximum horsepower and torque, and print-out the results so their tractor(s) will be truly competitive on the track.

Engine Dyno Rental Fee: $30.00 per hour run time from the moment the engine is started. No setup fee for Cub Cadet engines with a 3- or 6-pin/stud clutch driver. An adapter may need to be needed or fabricated for other makes and models of engines. Only engines with the narrow base oil pan can be tested. Engines with the wide base (tall) oil pan cannot be tested at this time.


To place an order and/or for technical assistance, please contact:

A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell). 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.) A-1 Miller's shop is open to the public from 9am to 5pm, including weekends (except Holidays). Please call before coming so I'll be here waiting for your arrival. Fax: 1-573-449-7347. E-mail: pullingtractor@aol.com. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can always make the long drive to A-1 Miller's shop to personally drop off and/or pick up your engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long."

To place an order, please call the number below Ê or send an email with your name, complete and correct postal address and phone number and so I can figure the total with shipping cost and USPS Tracking. For payment options for parts ordered or services performed, or to make a donation to my websites, I accept cash (in person), USPS Postal Money Orders, cashier's checks, business checks, MasterCard, VISA, Discover, American Express (please add 2.5% to the total for the credit/debit card processor's surcharge), Western Union Money Transfer, MoneyGram Money Transfers or Popmoney. (If a part for a specific purpose is special ordered, your debit/credit card may be charged for the full amount or as a deposit right after your order is placed; please do not send your debit/credit card information in email!) Or you can pay 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 and correct postal address, phone number and a description of what the payment is for. My mailing address and phone number are below Ê . I'll make a note of your order, and I may have to order some of the parts, which should take a few days to come in, but I will send the parts to you as soon as I have everything in stock after I receive your payment.

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

To figure the shipping cost, I weigh the package with the parts, then I go online to the USPS Postage Rate Calculator website. I type in the weight, my zip code and your zip code, then it shows me the prices for various ways to ship the package. I always choose US Postal Service because I believe that's the most fastest, economical and reliable method.

Shipping: (United States and it's territories)
To save you shipping charges, item(s) in a package or cushioned envelope weighing less than 13 oz. is sent by First Class Mail for a 2-6 day delivery. Most packaged item(s) weighing over 13 oz. is sent by US Priority Mail for a 2-3 day delivery. To save you even more on shipping heavy items, I always try to use the US Postal Services' Flat Rate Priority Mail envelope and boxes (if the item(s) can fit inside the envelope or boxes). Some heavy items weighing no more than 70 lbs. is sent by US Mail Parcel Post. Item(s) weighing over 70 lbs. is sent by FedEx Ground. Again, if you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can always make the long drive to A-1 Miller's shop to personally drop off and/or pick up your engine, transaxle, tractor, etc.

Ship to Canada and Worldwide þüý -
Item(s) in a package or cushioned envelope weighing less than 1 lb. is sent by US Postal Service Airmail Letter Post for a 4-7 days delivery. Packaged item(s) weighing over 1 lb. and up to 66 lb. is sent by US Postal Service Airmail Parcel Post for a 4-10 days delivery. I cannot use the US Postal Services' Flat Rate Priority Mail envelopes and boxes to ship outside U.S. territories. Item(s) weighing over 67 lbs. or more is sent by FedEx Ground or equivalent services.


Official PayPal Seal We Accept PayPal, Visa, MasterCard, American Express & Discover Credit & Debit Cards Western Union - Send Money - Money Transfer - Find Location - Transfer Money
(When placing an order through PayPal, please provide a list of which parts you need.)

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


à Return to Main Pulling Tips Page | Return To Previous Page | Reputable Garden Pulling Tractor Engine Builders, Parts Suppliers and Service Providers | Hot Links to Reputable Garden Tractor Pulling Clubs and Associations | Top of Page

Copyright © 1996-Present. This website created, designed and maintained by Brian Miller.