Home › Forum › Ask A Member › Runaway motor with plug leads removed › Re: Runaway motor with plug leads removed
It absolutely can and does happen!
Turning the key off wont stop it. Nor will pulling the spark plug leads. Nor will pulling the fuel line, as it will run on the fuel in the float bowl. The only way to stop it is to take a rag, and cover the intake of the carb and seal it off.
What causes it is carbon build up in the cylinder. That, and a lack of backpressure on the exhaust while running. Happens while running on muffs mostly, on bigger HP motors. Small hp motors are not as prone to it. I have a large test tank, so I have never encountered it, but my neighbour that loved to rev up his big old girl in the drive way on muffs threw a piston one Saturday afternoon after I had warned him against that practise many times.
Moral of the story, don’t rev up motors without sufficient backpressure on the exhaust, and keep them carbon free. I do annual de carbs with seafoam, or OMC engine tuner. Do at night, or your neighbours will think your house is on fire!