Proper ignition timing is critical to a well running engine. Just like a car, a lawn mower engine works at its most efficient when the timing is set correctly. Correctly set timing allows the spark to ignite the compressed air-fuel mixture when the piston is in position to deliver maximum power. This dance of perfect conditions is also known as before top dead center BTDC. If it sparks too early, you may experience kickback.
Too late, there is a severe lack of power. An understanding of internal combustion engines is needed for this project. Expose the contact points and condenser of the engine. These parts are located under the flywheel.
Remove the flywheel nut, washer and key. The coil is on the top of the flywheel. Look for the square hole in the stator and the round configuration of the coil. Tighten the stator bolts so the stator becomes fixed and will not move.
Now, rotate the crankshaft until the point arm is resting on the high side of the ignition cam. Use the screwdriver and set the feeler gauge to 0. Once the gap is set, clean the contact points with lint-free paper. Release the stator to its original position. Reinstall the flywheel key, washer and nut.
Rotate the flywheel to check for any striking points. If it moves without binding, you are finished setting the timing.
If it binds or gets hung up, remove the flywheel again and look for possible problems. Elizabeth Sobiski has been writing professionally since She provides businesses such as Burdick and Lee Galleries, Clearwater Fishing Charters and Read Finder with custom content to keep their digital and print media fresh, informative and directed to their target audience.
Tecumseh LEV120-362001A Parts Diagrams
The key looks and works just like the original for less cost so I bought 3 of them to keep on hand because they are easily deformed. If the key becomes deformed partially sheared your engine timing will be off because magnets in flywheel will pass coil at a different moment than designed for efficient spark so engine will be hard to start or lack power.
To illustrate how easily they are damaged - I tightened the flywheel nut only about half as tight as specified to make flywheel easier to remove from tapered shaft since the tighter the flywheel nut the hard er it is to break flywheel loose from tapered shaft after removing nut.
Any little adjustment of points gap or opening timing requires flywheel removal so I had flywheel on and off a dozen times as I was fine tuning things. I did tighten flywheel nut as firmly as I could by holding flywheel from turning by hand as I tightened nut - apparently that wasn't tight enough. Just the act of pull-starting the engine with half tightened flywheel partially sheared the key! Unqualified recommendation.
Condition is New. Tecumseh Flywheel Key. Honda Z0L Carburetor Craftsman 42in. Lawn Mower Deck Rebuild Assembly MTD Mower Blade, Your mower does not start.8 hp to 10 hp Tecumseh, flywheel swap.
Sometimes it fires weakly, but yanks the starter cord from your hand. Your flywheel key is sheared and it needs to be replaced. The flywheel moved and sheared the key. Now the engine timing is very much incorrect. The spark comes at a time that makes the engine want to run backwards, but it cannot.
As a safety precaution, always remove the spark plug wire before working on a small engine. Did you use this instructable in your classroom? Add a Teacher Note to share how you incorporated it into your lesson. The flywheel key shears to protect the crankshaft from twisting, which would cause a very expensive repair. A soft key allows the flywheel to move on the crankshaft when your mower blade hits a tree root, an old stump, a large dried clod of dirt, etc.
If the mower blade is loose, that will cause enough shock to shear the flywheel key, too. Pictured is a repair I made to the blade holder. It had two raised tips to fit the blade slot. Those had become battered and the blade had some looseness, no matter how tight the center bolt was. I drilled out the tips and replaced them with hardened bolts.
Because of space limitations, I had to grind one side of each bolthead away at the top of the blade holder. This blade is actually a thatching blade. Somehow it is causing flywheel keys to shear. I think I will no longer use a thatching blade on this mower. Although sold by Sears, my mower engine is made by Tecumseh. There are several flywheel keys used on Tecumseh engines.Log in or Sign up. Sign up now! The U. Chamber of Commerce offered guidance on the loan.
Click here to learn more. Messages: 7. I'm new to this site, and trying to repair my lawnmower engine - it is a Tecumseh TVS this is stamped on the side. It was used by someone not myselfand it made a funny noise, so they stopped using it. It turned out the blade had half-loosened, such that it would have spun around degrees before the crankshaft caught up with it again - this would have caused sudden changes in the speed of the engine for sure.
I then tightened the blade, tried to start it, and it kicked back very badly, pulling the starter cord out of my hand. It kept doing that every time I tried to start it in fact, it would run backwards for a while, by doing the kick-back, and then turning backwards slowly, but just fast enough, so it would keep running barely backwards.
It is very, very slightly worn, but I don't think this would be causing the current problem or the issue in 4 below 4 Removed sparkplug and checked where TDC is using a screwdriver to detect the piston movement. I was wondering if the crank was twisted, but, it is quite a short crankshaft, see the diagram in the link above and it is quite thick; I can't imagine it could twist 90 degrees without damaging the flywheel key, and without any bending of the crankshaft occuring at all?
Thanks for your advice - will keep looking at the engine and see if I can figure it out but would be grateful if anyone could help me with this!
Any ideas anyone? Messages: 2, The engine is an old points and condensor ignition--unless someone has chipped it. The points are in a case under the flywheel. Honestly, I'd replace the points and condensor. Adjust the points to.
When you pull the cover off the case containing the points, rotate the crank until the lobe of the crank opens the points to its maximum and if it differs greatly from the figure above, that is most likely the problem.Hello, I have a 3.
Recently a bolt fell into the flywheel cover and jammed the flywheel, It wouldnt even move. People sayed its the flywheel key woodruff. So I ordered a replacement one for the motor. My question is how do I take off the flywheel and how do I inatall the key? Can I use a Air Wrench, or what should I use?
Please help I want to get it running again. The key is a simple replace, once the flywheel is removed, you will see an alignment groove on the crankshaft and on the flywheel.
Ensure the groove is clean. Place the new key in the shaft groove and carefully replace flywheel. Can be a bit tricky but with a few tries it's done.
The flywheel fits onto the tapered crankshaftt and is held down with a nut at the center that is tightened to the end of the shaft. You will need to remove the flywheel cover, remove the flywheel nut, and then remove the flywheel. You can use an air wrench to remove the nut, but you should use a torque wrench to retighten it when you put it back!
It is made that way so that the wheel will not loosen accidentally. You will need a flywheel puller to pull it loose from the shaft. You may be able to borrow or rent one at a parts store. Connect the puller to the flywheel with the threaded arraingment on the wheel and tighteen the puller until the wheel "pops" off. Do not use an air wrench for this. Use a regular or torque wrench.
Tecumseh Flywheel Keys
When doing a Tecumseh small engine repair project or performing maintenance, think Jacks. This item qualifies for free shipping to the lower 48 U.
Height 0. Length 0. Width 0. Tecumseh Flywheel Keys We have replacement Tecumseh Flywheel Keys to help get the ignition system for your Tecumseh small engine up and running again. Qty: Please enter numbers only for Qty. Equipment Type Small Engine. Bulk pack Priced per pack, sold per pack Order as 1 to receive 25 Length 0.
Free Shipping This item qualifies for free shipping to the lower 48 U. Connect With Us:. Flywheel Key. Tecumseh :. Tecumseh : Pack of 5 Flywheel Keys. Flywheel Key Shop Pack.