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Can you fix a fouled plug?

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Old 07-14-2003, 11:28 PM
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aftcg
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Default Can you fix a fouled plug?

Do you just toss a plug if it fouls out due to wrong adjustment on the carb needles?

Someone mentioned to me that you can heat the element with a torch and it will be good as new.
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Old 07-15-2003, 03:12 AM
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Default Can you fix a fouled plug?

At the flying field, in order to fly my gasser, I've scratched them out with a awl or fine wire. But for no more than they cost, you would be trouble ahead, to get a new plug before flying again?

Glow plugs, I just toss them. They are over there in the grass somewhere?

Enjoy,

Jim
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Old 07-15-2003, 03:28 AM
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Default Can you fix a fouled plug?

Running a rich mixture by itself will not foul the plug of a glow engine, assuming the fuel is good and of proper content and ratios.

I have heard of people burning off accumulated castor varnish by using a match or a torch. It hardly seems worth the trouble with glow plugs as inexpensive as they are. I wouldn't bother doing it.

Nothing will restore a glow plug that has been ran too lean and made frosty in appearance.
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Old 07-15-2003, 11:32 AM
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Default Can you fix a fouled plug?

Not worth the hassle. Just a temporary fix.
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Old 07-15-2003, 12:02 PM
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Default Can you fix a fouled plug?

I asked the very same question on either the SA or gsal list about a month ago. I'll try to find the thread when I get home and post a link. The gyst of the answers were either the air type of sand blaster cleaner, and soaking in carb cleaner. I tried the sandblaster but wasn't at all satidfied with the results. No matter how hard I tried, or what I did, I never got ALL of the sand out. I opted for the carb cleaner, but honestly it isn't what I was hoping for either. It cleans them pretty good though. I suspend the plugs in a one gallon can of NAPA carb cleaner. I'll try to get that link for you_bob
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Old 07-15-2003, 12:17 PM
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Default Spark Plugs

I've been in the marine business and we used to get fouled plugs on the older outboards all the time. We always used the drop test method. Hold the plug over the back of the boat and drop it. If it floats its good. Just kidding. I agree with the sand blast comment. You never get it all out and sooner or later it will end up in the engine. For the price, just replace it.
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Old 07-15-2003, 12:21 PM
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Default Can you fix a fouled plug?

A spark plug, which has been fouled to the point of running bad, should be tossed.

The ceramic is a bit too porous to ever get "all" the carbon out, in most cases,
which is why it is generally only a "temporary" fix, as someone else suggested.

Plus, sometimes there are cracks in the ceramic, in places you can't easily see.

For the cost of a new plug, just buy a new one. This is a nice, cheap annual PM anyhow.

If you're fouling the plug out more than once in a year, you might take a
serious look at your adjustment methods, oil type/quantity, etc... something is wrong.


and paero, I like that drop/float test... a lot
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Old 07-15-2003, 12:47 PM
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Default Can you fix a fouled plug?

Spark plugs did not have elements, the last time that I looked, so I assumed he was talking about a glow plug.

I have a mish-mosh of groups in my subscribe file and often do not notice which forum something is posted in. If this is posted in the gasser forum, "never mind!".
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Old 07-15-2003, 01:24 PM
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Default Can you fix a fouled plug?

Maybe we need to distinguish between fouled and dirty. The plugs I would keep would be the "dirty" ones, and toss the fouled ones. What are the characteristics of a fouled plug_bob
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Old 07-15-2003, 03:40 PM
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Default Can you fix a fouled plug?

The black carboned ones are the ones to fling. Carbon is an electrical conductor so the easiest path for the spark is down the side of the ceramic so no spark at the gap. The black carbon is usually caused by running the fuel, air mix to rich.
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Old 07-16-2003, 12:56 AM
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Default Can you fix a fouled plug?

Clean them up with a wire wheel (fine mesh) then re-gap the plug. I then clean it with carburetor cleaner to make sure their isn't any residue and then install.
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Old 07-16-2003, 01:10 AM
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Default Can you fix a fouled plug?

A good gun cleaning solvent such as Hoppe's #9, or eqivalent, will absolutely remove the carbon. That's what gun cleaners are designed to do. Let soak for 24 hrs or more.
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Old 07-16-2003, 01:37 AM
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Default Can you fix a fouled plug?

Cleaning a spark plug with a wire wheel can actually foul the plug worse.

The ceramic insulator is harder than the wire and will cause metal from the wire brush to rub off onto it leaving a metalic conductive path that shorts the plug.
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Old 07-16-2003, 01:55 AM
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Default Can you fix a fouled plug?

I've seen a lot of plugs cleaned that way, but GeraldO is correct, and I've
seen the silvery-grey coating that a wire wheel can leave, firsthand.
Obviously it depends on the intensity of your cleaning, and "mild" brushing isn't "as" bad.

Why chance it? The plugs aren't "that" expensive.

Heck, I've blown through two or three SETS of plugs, in a weekend, just trying to nail
down the correct cam/ignition timing/jets/power valve/whatever in my street car, before.
Sure as heck never gave a second thought to cleaning them up.
Just can't stand a skipping car

I would like misfires even less, on a single cylinder airplane engine, I imagine.

Today's plugs don't seem to handle fouling and re-cleaning, as well as they used to.
(That's generally speaking, of course. I'm sure there are exceptions)
I own one of the sandblasting contraptions for plugs, and I was never impressed.
(Even if you DO get all the sand out of the thing again... which is a pain in itself)
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