L100 engine issues

Good evening, while cutting my mower made a loud popping noise and shut off. Removed the spark plug and was able to move the flywheel by hand. Put everything back together and it tried to crank it and it shut off again. Now I can't move the fly wheel at all.....and I'm a big guy. I did notice the key appears to be sheared, but would that cause the flywheel to move at all? Or is there a larger problem that will be found once I take the flywheel off? Thanks for your help......

what exactly caused the pop noise and if you remove the spark plug does the flywheel still get stuck?

please reply

PJ

Sent from my iPad using LMF

Not exactly sure. Didn't hit anything that I am aware of. Yes spark plug is out and still no movement. I'm tellin you I'm pulling as hard as I possibly can and getting no movement at all.