I have a Scag Turf Tiger with a Kohler 22 hp engine. It will turn over but will not start. It is getting fuel and there is spark to both plugs. What could be the problem?

Could be the flywheel key. And yes you can get spark with a flywheel key sheared, just not at the correct time. Is it backfiring, or sounding weird when you try and start it?

Mower man, thanks for your help! I really appreciate it. I did get the mower started! I cleaned and rebuilt the carburetor, and it started right up. Gas was getting to the carburetor but obviously the incorrect mixture was being supplied to the engine.
:) :)