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!
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#2
AnthemBassMan
Take the shroud off the engine, then remove the large nut on top of the flywheel. Might be a 15/16" socket that you use. See if the key has been sheared. If it has, it will not fire what-so-ever. The groove in the flywheel and the crankshaft need to be held in place with the key. If it is sheared, they only run a couple bucks for a new one...
Thanks for the information. The shear key is in fact broken and the shaft has rotated 4-5mm and the engine has no compression. Uh Oh... a rod failure maybe?
#5
AnthemBassMan
Could be that or even a bent, broken, or stuck valve. That's where you'll have to tear into it to find out. You could take the valve cover off and crank the engine to see if they are opening and closing. Chances are if they are, then it may be the connecting rod and/or piston...
