Just to clarify it was genuine alloy flywheel keys being used not a steel one?
I really honestly fail to see how a grabbing starter can cause this, the teeth on the starter are plastic, they shred before anything else breaks.
The flywheel has to be pulled down TIGHT, with the big flat washer under the nut, we're talking the same flywheel key as used in small 2hp engines, except the flywheel is a lot heavier in a 12hp. if the flywheel is not bolteddown tight enough it will break the key with ease.
If you get stuck for a crankshaft or getting it repaired, I will check later I may have a 25cube crank floating around, forsome reason though I think all my bigger engines are 28 cubic inch.
