Lawn Mower Problem

[Ulysses]

Shear key then. Do they have those?

A misaligned ignition module could keep it from turning.

[clare]

But the flywheel key being sheared CAN make cranking it with the ignition on a challenge. (spark occurs with the piston just over half way up - yank the cord right out of your hand

[Nate Nagel]

agreed, this is a common failure with Tecumseh engines. I had a handful of Tecumseh flywheel keys on a shelf in my garage when I lived in Michigan. My neighbor/landlord was always bringing his mower over for me to fix and it was always the same failure, I guess they were hard on mowers/never picked up all the rocks in their yard/mowed right over roots and stumps. Inevitably it was the flywheel key (a soft metal key on those, not a pin) the reason it won't start is because the trigger for the ignition is on the flywheel, once the flywheel spins on the crank the engine is out of time. Starts running bad the first time you hit something and if you hit another something it'll knock it so far out that it won't start anymore... symptoms exactly like the OP's. Kicks back when you start, etc. (because the timing is too far advanced for the engine to run)

The fact that I could "fix" lawnmowers and was able to repair a busted window and "restore" (really just strip off years of sloppy painting and re-clear) the old brass door hardware got me loads of brownie points. I think I also tarred the cracks in the sidewalk so the weeds wouldn't grow up through, edged the walk, weeded the flower beds (actually I usually just threw my grass clippings in them and then only pulled up the weeds that managed to get through all that,) and did a couple other little things and my landlord was just blown away. Makes you wonder what the average tenant was like...?

nate