I have a Generac Guardian (Model 04456-0) 12kw generator. The flywheel has to be replaced, because for some reason the starter and flywheel got out of alignment and the flywheel has been damaged. The generator has only 63 hours on the hour meter.

My questions;

1) What might cause this to happen?
2) Once the enclosure is removed, what is the best way to go about replacing the flywheel?
3) What other parts in the area of the flywheel & starter should be investigated before replacing the flywheel & starter?

Thank you very much for any help,