Small Engines (Lawn Mowers, etc.): mower wont start, flywheel key

Question
I have a 2 year old Cub Cadet self propelled mower. I recently inadvertently ran over a piece of wood on my lawn and the mower shut off. Upon restarting the mover backfired and some black smoke came out.  Now the motor will only start for a few seconds and shut or will not start  at all.  Any ideas on how to fix or have I fried my mower?  Thanks

Answer
The flywheel may have shifted.  This would put the ignition out of time and is fairly common.  If you remove the covers and nut over the flywheel, you should be able to see if the flywheel is aligned properly.  There will be a slot in the flywheel and crankshaft that an alignment key fits into.  If the flywheel shifted, that key will be sheared.

To reset the flywheel and replace the key, the flywheel will need to be pulled.  The key will need to be replaced to set the timing and the flywheel re-installed.  We usually lap the flywheel to the crankshaft with very-fine lapping compound when replacing the flywheel.

If you have any questions or the key is still in place, let me know and we'll go from there.  Thanks, PK.