Sparks inside the cover of push mower

[mancave]

I have a push mower that runs just fine. I was mowing after dark tonite and noticed there are sparks inside the cover, meaning where the pull string is located, or by the flywheel. That has me puzzled. If that is not strange enough, just to see if the sparks would stop with the spark plug wire removed, I popped the spark plug wire off while the engine was running, using a dry wooden stick. There was a strong spark that snapped against the head of the engine, and what was really bizarre, is that the engine kept running with the spark plug wire removed. At first it arc'ed over to the plug, but I pushed it 2 inches away from the plug, and it was snapping against a head bolt, and still kept running. That makes no sense at all. How the f*ck can it keep running? All I can think is that the engine was hot enough to ignite the gas, because it was very hot after mosing down some 2 ft. tall grass and weeds.

This is a real puzzler!!!

[micky]

I think maybe you invented the diesel engine. Mosing is very much related to dieseling.

Maybe a hot piece of carbon in the cylinder is igniting it.

Some cars keep running and they call it detonation or dieseling or a third thing, depending on a couple details.

Actually I don't know.

[micky]

After-ignitiion is, I think, the third term.

[Tony Hwang]

Hi, My take on it is, ignition module is breaking down leaking the current. Take a look at it. There may be a carbon trace.

[micky]

I dont' get it. Leaking what current where?

Regardless, how would that get the spark plug to emit a spark? The wire is off the sparkplug, 2 inches away, and no arcing is seen.

Surely a leak from the ignitiion module, outside the cylinder, is not igniting the gas in the cylinder.

OP, you could try this after dark, or after you roll the mower into a dark garage. Maybe you'll see some more arcing somewhere.