Outdoor Power Equipment and Small Engines - Craftsman 11HP backfired, now no-start

Picked up an older Craftsman 11hp tractor, started great, mowed my lawn great, but when i put it away i was still on fast throttle when i shut it off, then BOOM, good backfire, now will no restart. Cranks over fine, just wont fire.Any ideas on where to begin?

darryn
My first guess would be to check the flywheel key in case it sheared.

snoman

While the flywheel key (ignition timing key) is possible, it is quite rare on riding mowers for it to shear. Being an 11-horse, it is most likely a Briggs & Stratton engine. Post back with the engine ID numbers (model, type and code) so we know just how old it is. In other words, I'd like to know if you have point ignition or solid state ignition. Perhaps, though, you have a spark plug that fouled and simply need a new one. Check for spark at the spark plug and, if not, try a new plug and check again. Post back with the results.

ok men, i have a Model#917.254272, it says electronic ignition. Today i pulled the plug, it was wet of course, i gave it a litle clean since i had no replacement, then put it in the ignition wire, held it to ground and cranked it and there was plenty of spark. I then put my finger over the spark plug hole, and barely felt anything! In fact, i can turn the motor over with 2 fingers on the flywheel! Us auto mechanics are thinking of compression rates of 140 psi or more, and this certainly does not have that! It seems to pop back thru the carb when starting is attempted.

Sounds like a valve is hanging open.

Or, a valve seat has loosened. You'll want to pull the cylinder head and have a look in the combustion chamber. Engine model, type and code numbers, please!