FYI. I got the following reply from Kohler:
Hello Mr. xxxxx
Thank you for your inquiry.
This is an unusual failure that we usually see as a result of excess heat,
or by some sort of impact to the flywheel. While this engine does have a 2
year warranty against defects, I will make a goodwill policy adjustment, and
send a flywheel and stator free of charge. Please let me know how this works
for you and of course, if we may be of further assistance . Thanks again!
I guess I can't complain about that!