What exactly is a fouled plug

[kenimpzoom]

What exactly is a fouled plug?<br /><br />Is the plug not working because a carbon path has built up between the center electrode and a ground, and the plug is shorted?<br /><br />OR<br /><br />Is the plug not working because carbon build up has made the resistance so high, the voltage is not able to jump the gap? If so where does the spark go?<br /><br />Ken

 

[ob]

Re: What exactly is a fouled plug

Several different categories of fouled plugs.Basically any condition that will alter the normal firing of the plug.Oil fouled ,gap bridged fouled,etc..

 

[Homerr]

Re: What exactly is a fouled plug

You're right OB...<br /><br />I was always taught that a plug is fouled when something bridges the center electrode and ground.<br /><br />Most of the time it's carbon.<br /><br />I've never heard of a plug having too much resistance. Most of today's modern ignition systems pack a mean spark, and will keep on working unless it's completely shorted (fouled).<br /><br />If your ignition system is weak to begin with, then I guess I could see a resistance issue happening.<br /><br />Heck.. what do I know anyway? LOL.<br /><br /><br />H.

 

[Boomyal]

Re: What exactly is a fouled plug

I've heard that repeated flooding with gas will render a plug unsalvagable. In that event you would see no visible build up on it.

 

[kenimpzoom]

Re: What exactly is a fouled plug

The reason I ask is, I have a dirt bike that has a provision to run dual plugs. I want to run dual plugs from a single coil to make it easier to start if one plug fouls.<br /><br />But if it fouls by grounding, then having dual plugs running off one coil would be useless, cause the spark would just all go to the fouled plug (with no resistance).<br /><br />If it fouls by having a high resistance, then the other spark plug would work.<br /><br />Ken

 

[SS MAYFLOAT]

Re: What exactly is a fouled plug

Ken, I have seen instances that a plug can be clean, look great, sparks excellent when tested outside the combustion chamber. But however when it is installed and put under compression that they won't fire. Not sure why this happens, but it does. This would be one of those apps that a dual plug can work for you.

 

[Terry H]

Re: What exactly is a fouled plug

Carbon has a low resistance and therefore carbon fouling shorts the spark to ground...just a thought

 

[karrick]

Re: What exactly is a fouled plug

When I rode quads and bikes, I would keep an emery board in my toolkit. It the plug was carbon fouled, you could clean it of with the emery board in case you didn't have a spare plug handy, which I would reccomend.<br />Just my 2c

 

[one more cast]

Re: What exactly is a fouled plug

I once made a spark plug tester/cleaner from an old furnace transformer. I could take a plug that would not fire at all in an engine and when hooked up to the transformer for only a few seconds the plug would start to fire and after 20 or 30 seconds the plug would almost always fire normally.This tells me the carbon was not grounding the plug out but rather insulating the plug. So I believe your duel plug single coil will work.

 

[Bob_VT]

Re: What exactly is a fouled plug

Some plugs foul easier than others. I have found that NGK plugs will darn near fire while sumberged in oil. They get my vote for the best dirt bike plug.<br /><br />Bob