what is a "fouled sparkplug" ?

[casi77]

Ok, I have been reading some threads, people mentioning they are chaning the spark plugs because its fouled.. one instance the person changing it at every trip because its fouling.. can someone explain....

- why/when would a spark plug foul?
- how to test for a fouled spark plug?
- are some spark plugs better than the other in terms of not fouling?
- how to prevent spark plug fouling?

reason these questions come to mind is, I dont hear this much of spark plug fouling on automotive engines, and they are known to last thousands of km on an automotive engine.. knowing all this, and coming to a marine industry things not seem to be the same! one consideration being 4 cycle versos 2 cycle engines being one big difference.. other being marine engines run at constant high rpms.. any comments??

 

[tashasdaddy]

Re: what is a

Re: what is a

a fouled spark plug is when it isn't burning the fuel cleanly, usually leaving wet oilly deposits of the plug, thus causing it to misfire even more. can be from bad carboration, spark, carbon, compression, misadjusted gap, just to name a few. it's one of the first signs of a sick engine.

 

[AlanR]

Re: what is a

Re: what is a

Q) why/when would a spark plug foul?

A) Youd foul it when you leave the choke on or prime the motor to much basicly wets the plug to the point where it wont make spakr

Q) how to test for a fouled spark plug?

A) take it out and look at it SIMPLE if its dripping with gas and oil its fouled

Q) are some spark plugs better than the other in terms of not fouling?

A) No you can "Foul" any plug theres not really one better than the other


Q) how to prevent spark plug fouling?

A) dont leave your choke on or prime it so much

Also you dont hear about cars fouling plugs much because you dont mix your gas and oil and also most cars are FUEL Injected to prevent the car from fouling the plug ( one of the many reasons why cars are fuelinjected) On cars with carbs you can easly foul the plug by pumping the gas a couple of times.

 

[casi77]

Re: what is a

Re: what is a

thanks for the answers, now a fouled spark plug considered garbage or can it be cleaned and re-used?

Q) why/when would a spark plug foul?

A) Youd foul it when you leave the choke on or prime the motor to much basicly wets the plug to the point where it wont make spakr

Q) how to test for a fouled spark plug?

A) take it out and look at it SIMPLE if its dripping with gas and oil its fouled

Q) are some spark plugs better than the other in terms of not fouling?

A) No you can "Foul" any plug theres not really one better than the other


Q) how to prevent spark plug fouling?

A) dont leave your choke on or prime it so much

Also you dont hear about cars fouling plugs much because you dont mix your gas and oil and also most cars are FUEL Injected to prevent the car from fouling the plug ( one of the many reasons why cars are fuelinjected) On cars with carbs you can easly foul the plug by pumping the gas a couple of times.

 

[AlanR]

Re: what is a

Re: what is a

burned off with a torch or just dryed off with a cloth

 

[DHPMARINE]

Re: what is a

Re: what is a

for the price of a plug .... replace it.

also most current engine ignitions can fire a 7/16 " spark.

if you have a fouled plug,it is defective,or real problems are going on.

Some one here posted a sparkplug test quite a while ago ....

something like place the plugs in your palm and lower your palm into the water.Turn your hand palm down,and back again.The remaining plugs are the good ones.

DHP

 

[AlanR]

Re: what is a

Re: what is a

DHP's got a point, what are they 2.99 at Walmart but if your in a pinch and dont have a walmart close just whipe em off or burm em off

 

[DHPMARINE]

Re: what is a

Re: what is a

And don't do the plug test in the middle of the pond with the only plugs you have.

DHP

 

[R.Johnson]

Re: what is a

Re: what is a

Any plug that has been run in an idle'd two stroke will show a wet surface. With today's engine's with electronic ignition, the ignition will blow right through this fouling. The day's of a fouled plug, or a flooded two stroke are gone, If the engine is in proper sync, and tune, the engine will start, and run. It will blow the unburned fuel right out the exhaust ports.

 

[iwombat]

Re: what is a

Re: what is a

tashasdaddy was a little closer to the answer.

Plugs can foul for a variety of reasons, and the reasons are different for 2-strokes vs. 4-strokes.

Generally, fouling falls in one of the following categories (And I'll just bet I left something out).

1) Oil fouling - excess oil in the combustion chamber.
2) Fuel fouling - improper fuel mixture and incomplete combustion.
3) Heat fouling - plug of the wrong heat range.

Your manual should have examples of several kinds of fouling and nice pictures for each one.

 

[iwombat]

Re: what is a

Re: what is a

Reading that again - the first line doesn't exactly read too well.

What I meant, was getting back to the original question, the first response was on the mark about all the reasons plugs might foul. Just shifting focus back to the original post a bit.

 

[papasage]

Re: what is a

Re: what is a

i have herd some boat owners say the add a little more oil to the gass to be sure . when i did that it would foul a plug . the surface pluggs will foul easier that the gap type . and a lot of idling or slow running on the older moteor will foul plugs .

ps found plugs at wal-mart for my motor on a special rack QL77JC4 @ $1.00 a pice 8) bought all they had d