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Thread: How to decarb?

  1. #1
    Petty Officer 1st Class
    Join Date
    Jul 2002

    Default How to decarb?

    Where can I but the fuel additive to decarb my motor? How often should it be done? I have a 2000 Merc 40 with around 55 hours on it. Thanks

  2. #2

    Default Re: How to decarb?

    SS,You can buy "ring free" products from your Merc. dealer that you can add directly to the fuel.Otherwise, the decarb. process involves injecting a decarb. product into the carburetors while the engine is running. It's an all day process, including the soak time.Do a search on the baord using the keyword-"decarb". Get a cool drink, there's plenty to read.

  3. #3
    Supreme Mariner roscoe's Avatar
    Join Date
    Oct 2002
    Medford WI

    Default Re: How to decarb?

    Decarbing is a 2 part process. The first part is preventative, done by using a fuel additive to prevent carbon build up. SeaFoam or Ring Free are such fuel additives and can be found at most auto parts stores. It also works as a fuel system cleaner and should be used as a preventative maintenance procedure.If your intent is REMOVE the existing carbon buildup from the cylinders, heads, and rings, then a spray decarb solvent product is needed. Buy at least 2 cans of decarb. Some people use one can per cylinder.Run engine at fast idle, with engine running, slowly spray liberal amount into each carb,spray some more, spray a larger amount into carbs until engine chokes out and stops,remove spark plugs and spray decarb liberally into each cylinder, install the spark plugs, let it soak for 1 to 10 hours. Start the engine and run at medium throttle, or if at the lake, run it at full throttle. It won't hurt to spray some more through the carbs. Run it for atleast 10 minutes to flush the crud out of your engine. Now remove and clean, or replace the spark plugs.

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