Small Engines (Lawn Mowers, etc.): INtek engine seems out of time, hp unit, time dad

Question
Dad has a intek engine in a 5 year old craftsman rider.  this is an 18.5 hp unit Mower YT2000 engine 31T7770299EI.  the bolt came out of the rod and bent the rod so they replaced the rod and ground the crank 20 thou over.  When they tried to start it after putting it back togehter it backfireda and sheared the flywheel key.  He has checked the timing marks on the cam and crank and they line up.  Waht else should they be checking.  the valves seem to open and close when they are supposed to be in relation to the piston reaching tdc.  Please help
Thanks

Jeff

Answer
When you reassembled the engine did you line up the timing marks on the crankshaft and the camshaft?

Is your valve clearance set properly?

Was your camshaft damaged when the rod broke?   

These are the most common things we look for in the service center.

HTH