Flywheel key replacement

JDgreen227 · May 1, 2012

Yesterday I pulled the flywheel on my step mom's '05 vintage Craftsman to replace the flywheel key on the Tecumseh, and I got to wondering:

Exactly what is the purpose of putting a key atop the engine, when it seems having a key down at the blade would be much more practical and much easier to replace should it be required? If you hit something and the blade bends, you are going to end up removing and replacing it anyway so why don't they put the key there in the first place? She told me she got one estimate of $50 to replace the key on her mower, which I thought was simply obscene as it is a half-hour job and only a $1 part.

greasemonkeyok · May 1, 2012

I thought all small engine flywheels had a keyway and key. While it is certainly not proof positive, at lease everyone I have worked on did. Flywheel is harmonically balanced, and that is the only way to ensure it is aligned up properly with all the other stuff in the innards.

As for the price, mmm I donno. Soak it with penetrating oil, align and install wheel puller, twist and tap gently, then pick up the pieces when the flywheel pops off, falls to the floor and breaks off a fin. Go to the salvage yard to buy a new flywheel (and of course, it is harmonically balanced for a different but similar engine). For $50? Not me.

JDgreen227 · May 1, 2012

Actually I know how to remove a flywheel and I have a correct puller. Photo shows the broken off key...a $1 part the repair shop would charge my step mom $50 for labor to replace.