A BTW that isn't directly related...
Anytime you put the flywheel on, insert something (piece of wire, little screwdriver) into the crank slot to make sure the key didn't slip out the backside when you put the flywheel on.
You can easily feel that it's there. If it IS there...that's good enough. It can't be 1/2 way out as long as the flywheel is seated as it is supposed to be.
AND make sure the flywheel nut is properly torqued. If the flywheel gets just a tad loose, it will sheer the key.