She's been gracious enough to pose with some completed repairs. HELP! I'm trying to get her father's mower running. It's a Murray riding mower Model 40507x8 40 inch tractor with a Briggs and Stratton 28U707-0113, 12.5hp engine. I've replaced the fuel tank, fuel lines, fuel filter and on/off valve, spark plug, and battery. I've checked the safety switches at the seat, brake, and blade engagement lever. The engine spins strongly when I attempt to start it, but will not even attempt to "kick off". The flywheel on top along with the shaft exiting the bottom both spin. I've got a good spark from the plug wire boot to the spark plug and from the gap end of the spark plug to the engine block when I turn the engine over. I sprayed carb cleaner through the carb with the bowl off. Cleaned the air filter. I've fed starting fluid into the carb and even given a shot directly into the cylinder at the spark plug hole, yet the engine will not "fire". If you guys can give any advice, I would really appreciate it. Thanks a bunch in advance!