Roll the engine over by hand (pull the spark plugs out first) and check the flywheel teeth for damage. If the starter pinion has been bottoming out in ther flywheel, it might have chewed up the flywheel gear. The way to check for proper starter pinion engagement is top spray-paint the starter gear teeth, install the starter, and crank the engine over several revolutions with the ignition disabled. A properly-shimmed starter will wear the paint off about 3/4 of the depth of the tooth. It should not bottom out in the flywheel!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!