Originally Posted by johnp900
No, there is an issue with sheared keys. If the key is sheared, warranty should take care of the repairs. You can't shear a key by runing over the muffler.
My first thought was-"but he ran over the muffler and the key sheared".
That made me wonder- How long did you mow before the muffler fell off? If it fell off before, or shortly after, you began mowing, maybe the key was already sheared. You may not have had a chance to find out before hitting the muffler?
I'd check the key no matter what the reason.
Hopefully, they'll cover the repair bill and you have a good running engine.