MTD yard machine ride -on mower . 18.5 hp/42 inch Briggs & straton motor : ''Starter motor ( new ) can not turn the piston through the compression stroke . Even when I connect jumper cables directly to the starter motor terminals. Valves are opening and closing in correct stroke . Spark plug new , gets wet from fuel . Removed flywheel , all timming magnets good . Replaced flywheel in correct place as shaft has a key.
Initially the mower started and ran ,but I removed the brake for the blades (worn ) and ran the machine. When switched off the key the engine would backfire as the momentum of the blades still turned the engine.

Garden - Yard Machines