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Engine basics => Engine set up tips => Topic started by: Larry Renger on March 08, 2019, 07:31:46 PM

Title: White coat on plug element!
Post by: Larry Renger on March 08, 2019, 07:31:46 PM
I have had problems with the plug elements turning white, resulting in lousy engine runs.

What causes this, and how do you avoid it/and or better yet, cure it?
Title: Re: White coat on plug element!
Post by: Dan McEntee on March 08, 2019, 07:48:06 PM
   What brand of fuel is it? These might be the dreaded "taters" that Brett has mentioned several times in the past. he has seen them accumulate when using SIG fuel. I use SIG fuel and have never experienced them, but I don't run piped engines. When this has been discussed, I have wondered if this was a phenomenon related to using a tuned pipe. But I doubt that you are flying a piped engine, knowing you from your posts over the years. Gotta be something in the fuel or being ingested by the engine when running.
  Type at you later,
  Dan McEntee
Title: Re: White coat on plug element!
Post by: Brett Buck on March 09, 2019, 12:30:27 AM
   What brand of fuel is it? These might be the dreaded "taters" that Brett has mentioned several times in the past. he has seen them accumulate when using SIG fuel. I use SIG fuel and have never experienced them, but I don't run piped engines. When this has been discussed, I have wondered if this was a phenomenon related to using a tuned pipe. But I doubt that you are flying a piped engine, knowing you from your posts over the years. Gotta be something in the fuel or being ingested by the engine when running.
  Type at you later,
  Dan McEntee

    The "taters" are usually smooth blobs of a hard tan-colored substance, with a carbon coat, making them black. Scrape them and you usually see what looks to be melted plastic.

    Turning "white" is something else. I do occasionally see "frosted"-looking elements on other engines, and under a microscope you can see that the wire itself is eroding, causing it to be light gray and matte finish.


    Off-hand, I don't know the cause or cure, but its been around a long time. I have Tee Dee glow heads not run since the 60's that look like this.

    Brett