It looks to me like that key has been sheared off, and the tapered bore of the flywheel looks as though the saw was running with the flywheel loose and the taper bore has had some damage done to it.
Do your best to thoroughly clean up that bore and make sure the stub of the key is aligned with the keyway on the crankshaft when you reassemble the saw. Also be sure to torque the flywheel nut properly. You should have been able to get the workshop manual from the links in earlier posts.
Mark
Do your best to thoroughly clean up that bore and make sure the stub of the key is aligned with the keyway on the crankshaft when you reassemble the saw. Also be sure to torque the flywheel nut properly. You should have been able to get the workshop manual from the links in earlier posts.
Mark