The engine will turn over and will occasionally backfire, but the mower never actually tries to run. Would this be part of the kill switch under the seat or am ILooking in the wrong area.I tried removing the seat switch and shorting the connection, but still the same thing

If it backfires then there is some spark so its likely not a safety switch. Sounds more like a carboration problem. When did it last run well? Have you run into anything or hit a rock?

The back firing makes me think your flywheel key may be stripped or at least a ding in it enough to knock it out of time. Good luck

Agreed, that's wher I am going, could be out of timing