This Sprinter below was ripping the starter cord from my hand when I first tried to start the mower, the engine had oil in the combustion chamber and exhaust so I removed the spark plug and turned the motor over to remove the oil.
Dismantled the carby gave it a clean out reassembled the carby ,replaced the spark plug and I could not get it to kickback,started it at least 20 times.
The only other issue that may cause a problem is if the carby was over fueling or the valve guides or rings are worn which may cause the engine to hydraulic lock when starting, too much fuel or oil in the cylinder .
