Gas Lawnmower on 87 octane Dieseling due to engine temp hot carbon on head or mechanical failure
My wife ran to me to tell me that the mower wouldnt shut off after mowing on a hot summer day. I tried grounding the spark plug and it had no effect. I then pulled the spark plug wire off with insulated needle nose and it was still running. Instantly I knew it was then Dieseling on pure gasoline. Prior to the motor dieseling I heard a loud pop and it started burning lots of oil. I went to check on my wife when i heard the pop and saw the cloud of white oil smoke pouring out of it. When the oil in the cylinder burned off there must have been either a glowing carbon deposit on the head that was igniting the gasoline or the engine reached a temp in which gasoline no longer needed the spark plugs spark and at top dead center was hot enough to flash over and detonate causing it to diesel on pure fresh 87 octane gasoline. I ran into the house to get the camera to film this and then stopped the recording and was going to remove air filter on carb and smother it to kill the engine. By the time I found a flat head screw driver with many philips to be found I heard another loud pop and then it stopped dieseling and it sounded like the exhaust valve got seized = stuck open stopping the dieseling of the gas motor. Going to pop the head off of it tomorrow and see what kind of damage it has.