I have had push mowers come in where the owner cracked the flywheel from over torquing. Usually tecumseh engines. Had a Wilbur bring me an antique small outboard motor he broke the end of the crankshaft off when he tried rethreading the crank after he had stripped the fine threads. It was a good friends son so i fixed it. Turned a piece in my little lathe and welded it on rethreaded it and filed the keyway in the threads to match the taper. Wasn't perfect but the engine ran and the flywheel stayed on.