Small Engines (Lawn Mowers, etc.): Kohler 15 HP command, ohv motor, electronic ignition module

Question
I have a scotts riding mower powered by a Kohler 15 hp OHV motor. A couple weeks ago it ran out of gas just as my daughter finished cutting. we pushed it in the garage and it sat for a few weeks due to the hot dry weather. The other day my son put fuel in it and when he went to start it the battery was dead (the key was left on). During that time I smelled gas. I charged the battery and today I tried starting it. The engine turns over but will not start. When I first tried with the choke on, gas was exiting the engine through the muffler. I changed the plug and set the throttle on full (no choke) no gas is coming out of the muffler, but it backfires through the muffler when cranking. The plug looks dry, but it is black. I have good spark. I changed the oil thinking it had gas in it; there may have been a little in it but not much. If it were a car I would think that it jump timing due to the backfiring. What do you think.

Answer
Hi Kurt,

You're right, if it is firing but out of the muffler, I would suspect late timing.  Maybe leaving on the key caused a problem with the points (if equipped) or the electronic ignition module.  Before you get into that, since you have spark, I would squirt fuel into the carb and see if it will start, to rule out a lack of fuel problem.  With fuel and spark ruled out, timing would be the place to look.

Let me know how you make out.
Michael