My engine stalled today after I ran low on fuel. It would not fire up again, so I thought I would remove the plug and check to see if it was ok. It was completely dead. The coils looked fine, but it would not light up.

Is this pure coincidence or can running out of fuel burn out plugs? Bear in mind that the plug was only a week old.

Running out of fuel can burn up a plug. When running out fuel the engine gets very lean, hence hot for a short time = burned up plug. This most likly to happen with a weakend plug.

It's quite difficult to tell when it's about to run out of fuel, in enough time to bring it in and let it idle dry. I'm often at WOT when I hear it run lean (revs up really clean) at which point it has stalled.

Are you sure your igniter wasnt dead??

If the ignitor was dead ...Wouldn't it not fire up even the first time ???

A plug can die during a run and keep going till you stop the engine... I had a 15 min final on the weekend where the engine war running real hot, it killed the plug but it kept running for the entire race, when i stopped the engine i checked the plug.. it was dead.. I gues the heat from the engine can help the plug continue to glow as is the nature of glow ignition..

That is exactly how the plug works


CH3-NO2,
Get a timer if you don't have one built into the radio, most engines will run between 6-9 minutes on a 125cc tank, depending on conditions. If you came in every 5 minutes, you'd be fine.

A lean run out isn't only bad for the plug, it's bad for the motor too