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  #1  
Old 09-01-2021, 04:36 PM
gggflyer gggflyer is offline
 
Join Date: Jun 2021
Location: Scottsdale
Posts: 43
Default Spark plug question

Anyone know what that buildup is and what causes it. Mag on those bottom plugs and plasma on top plugs. Its hard like epoxy.
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  #2  
Old 09-01-2021, 05:17 PM
Full Throttle Full Throttle is offline
 
Join Date: Aug 2018
Location: Norwalk, CA
Posts: 64
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It's lead covered with oil. Plug is warn out. Mag is probably weak and needs an over haul. Change the mag, plugs and harness too.
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  #3  
Old 09-02-2021, 10:19 AM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Mags

Without knowing the specifics, mag history and time since overhaul, as well as history plug wires, this is very bad advice. New mag?? How about an overhaul by a qualified shop IF NEEDED like most of the world does.
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  #4  
Old 09-02-2021, 07:30 PM
PCHunt PCHunt is offline
 
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Location: San Diego, CA
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Where did you get the idea that Full Throttle recommended a new mag?
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  #5  
Old 09-03-2021, 12:19 AM
gasman gasman is offline
 
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Location: Sonoma County
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Quote:
Originally Posted by gggflyer View Post
Anyone know what that buildup is and what causes it. Mag on those bottom plugs and plasma on top plugs. Its hard like epoxy.
Start with a fresh plug. And see how long it takes to fail. Check the harness, then the mag.

How long of a flight did it take to foul this plug?? Maybe a broken ring.
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  #6  
Old 09-03-2021, 11:05 AM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Parts

"Change" certainly implies new harness and plugs. Change the mag would imply at least a remanufactured mag. With no history from the OP except the spark plug photo this is not good advice.
My 0 320 Lycoming nitride cylinders have never used a measurable amount of oil. 2700 plus nautical miles with no measurable oil useage. The bottom plugs were slightly wet for at least 100 hours.
The OP problem may very well have started with the picture plug being shorted with carbon. The first step should be a new plug, a runup and if everything is ok a test flight. Change mag and harness is just throwing money at a problem that has not been properly identified.
In the era prior to 100LL spark plugs sometimes had to be cleaned at 50 hours.
They usually looked similar to the photo.
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  #7  
Old 09-03-2021, 12:40 PM
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rv6n6r rv6n6r is offline
 
Join Date: May 2007
Location: Gearhart Oregon
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Oval center electrode, gap looks to be out of spec.
I would start with a new plug and check it again no less than 50 hours, assuming no bad mag drops or anything.
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  #8  
Old 09-03-2021, 12:57 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by gggflyer View Post
Anyone know what that buildup is and what causes it. Mag on those bottom plugs and plasma on top plugs. Its hard like epoxy.
Gap is WAY to big. recommend replacement. Build up is unclear, but need to confirm if that plug is even creating a spark. If not, that could account for the build up, though it could be several other things.

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  #9  
Old 09-03-2021, 01:52 PM
BH1166 BH1166 is offline
 
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Location: Eatonton Georgia
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Quote:
Originally Posted by gggflyer View Post
Anyone know what that buildup is and what causes it. Mag on those bottom plugs and plasma on top plugs. Its hard like epoxy.
Lead Ö. Bottom plugs donít scavenge as well as top. My top plugs are always perfect in looks and wear, the bottoms horribly full of lead no matter how much I leaned on the ground. Switched to 93UL. Lean, replace the plugs that look like this one, check every oil change. And LEAN when on the ground.
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  #10  
Old 09-03-2021, 05:31 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Spark Plug

The other thing we still don't know is the manufacturer of the plug. Champion used to be the gold standard, now they seem to have a lot of problems. This could have started as a plug failure not related to lead. 0 320 with 10-1 compression, carburetor, I do not lean on ground. The carb runs lean even with the mixture full rich.
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