What's the best way to de-carbonize a 4 MIX engine?

Discussion in 'Mechanic and Repair' started by john_incircuit, Aug 21, 2007.

  1. john_incircuit

    john_incircuit LawnSite Senior Member
    from NC
    Posts: 309

    What is the proper / best way to de-carbonize the 4 Mix engine? I just set the valves and changed the spark plug for the first time, was surprised how much carbon was on it.

    I read that Stihl has a special fluid for the de-carbonizing, but does it go in through the spark plug hole or through the exhaust port, should the valves be closed or open during the cleaning ... if the muffler has to be removed, do I have to use anti seize when reassembling ...

    Thanks!!
     
  2. mcdc6

    mcdc6 LawnSite Member
    Posts: 32

    go to your stihl dealer and ask for the instructions that come with the de-carbonizer. but the valves need to be closed and the fluid goes into the spark plug hole and the replace the spark plug and let sit for 8-12 hours the drain.
     
  3. G.M.Landscaping

    G.M.Landscaping LawnSite Senior Member
    Posts: 937

    When are you supposed to do this? I bought my fs100x at the beginning of last year, but I only cut 2 days a week. I thought it was at 100 hrs your supposed to do it.

    Maybe it's time I do this.
     
  4. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,104

    Do not get that de-carbonizer on your skin it will burn. It will turn the carbon to a paste like mess. Becareful not to let the paste mess get down into the engine when you clean it up.
     
  5. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,104

    Do not get that de-carbonizer on your skin it will burn. It will turn the carbon to a paste like mess. Becareful not to let the paste mess get down into the engine when you clean it up.
     
  6. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,104

    For some reason my post doubled. Feel free to delete post 5 (copy of 4) and post 6 (this post)
     
  7. SILVERSTREAK INC

    SILVERSTREAK INC LawnSite Senior Member
    Posts: 295

    rev the motor full throttle and spray some h2o into it from a squirt bottle, gets rid of all the carbon baby
     
  8. john_incircuit

    john_incircuit LawnSite Senior Member
    from NC
    Posts: 309

    You must have driven a muscle car years ago... I guess this could work, but I'm not sure if I'm man enough to try this out on the 4- Mix
     
  9. Fairway Land & Lawn

    Fairway Land & Lawn LawnSite Member
    Posts: 129

    I know it is tough with a string trimmer.....the four mix engines like to be run at WOT. My neighbor works for Stihl and tells me to run them all wide open. I have a Br550 that has well over 250 hrs on it and have never had a carbon problem. Run the string trimmers wide open for about 2 minutes at the end of the day, should get a cylinder temp to burn the carbon up...just my 2 cents....
     
  10. HenryB

    HenryB LawnSite Bronze Member
    Posts: 1,828

    How do you do this? Through the carb?:confused:
     

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