Riding Mower Won't Start - where to begin?

[bjordan]

Yesterday, I fired up my Poulan EX300 riding mower. It had been sitting inside my pole barn for three weeks. It ran fine 3 week ago and has been a fantastic mower. It started up but wasn't running at full power and eventually died. It would not start after that. I had driven up to my rural property for the day with my GF, in her car and didn't have any tools other than a pair of pliers. I took the fuel line off at the carb and gas flowed fine (tank was full). Next I sprayed some starting fluid into the air filter, to see if it would fire over. Nothing.

So, based on this incredibly basic "diagnosis", where should I start my trouble shooting when I get the mower back to my shop next weekend? The gas I filled the tank with was fresh. Spark will be easy to check once I have a spark plug socket in my hand, but it didnt fire over with starting fluid?...

Thoughts on where to dive into first?

 

[sgkent]

Check the oil to see if the float stuck and dumped fuel into the oil so it is too rich to run, then check the fuses, test for spark, if none then get a wiring diagram and start troubleshooting the circuit. Also look for mouse chew marks.

 

[bertsmobile1]

After checking the oil as per above , spray a SHORT SHOT down the plug hole
Engine should fire a couple of times if the valves are closed & the spark timing is right
If an inlet or exhaust valve is not fully closed it will backfire out either end respectively .
You said it was running under power the last time you used it and that suggests bad timing ( flywheel slipped ) or a bad valve ( stuck of lash incorrect )