How to De-Carb my pistons.

Discussion in 'Bubba's Outboards' started by jgdishon, Sep 16, 2006.

  1. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I recently did a compression test on my 1984 Mercury 50hp. All 4 cyl are at 125 and that's good but while cranking the engine I noticed small flakes of black carbon coming out of the spark plug holes. I shined a light inside and all 4 appear to have thick carbon on the piston heads. How do you clean them? I know my dad use to say if you slowly poured a mix of transmission fluid and water in the carb or your car while it was running it would clean the carbon off the pistons.
     
  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Get a spray can of engine tuner, or power tune, from a Merc or Johnson Evinrude dealer and follow the directions on the can.
     

  3. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I will do exactly that. Thanks
     
  4. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    Regular use of a good fuel stabilizer like PRI-G will prevent the problem from coming back .Also Yamaha I think makes a gasoline additive called Ring Free which is excellent at removing carbon.You might need to treat your engine twice due to its age and the amount of build-up,but once teated the Ring Free or even better,:smile2: continous use of a good stabilizer is good preventive maint.
     
  5. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    Thanks Jim I will try that.
     
  6. shorepatrol

    shorepatrol New Member

    Messages:
    63
    State:
    AZ
    seafoam , heard it works great
     
  7. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I put it in a spray bottle and after removing the plugs I sprayed it back into the cyl and let it sit for about 5 minuets. When I started it, it smoked like crazy for a few minuets then cleared up. After it ran long enough to get the engine warm I sprayed it into the air intake on my carberaters. When I was finished the water in my barrell that I had my motor in was covered with about 1/2 inch of black crud. I pulled the plugs back out and shined a light into the cylenders and they were clean as a pin. Thanks guys for the advise. Thanks Bubbakat
     
  8. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    Don't forget in your new found happiness to add fuel stabilzer and a can of ring free every now and then to keep those cyls clean.What Bubba didn't tell you is the other way to get carbon off if you let it build up again.You have to disassemble the engine,remove the cyls, grasp the connecting rods firmly and smash them on the sidewalk until the carbon comes off.This works well and carbon never builds up again after this treatment mainly because the engine never runs again.:lol: :roll_eyes: :smile2: :eek:oooh: :sad2: :tounge_out: :cool2: :wink:
     
  9. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I bought this engine used and I have just about rebuilt the whole thing. I wont let it build up again.
     
  10. catfisher43

    catfisher43 New Member

    Messages:
    910
    State:
    missouri
    i use the seafoam in my fuel.will it keep the carbon deposits out.thx in advance.
     
  11. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    I'm not sure because I don't use seafoam.If it is a fuel stabilizer it should reduce carbon build up.I would twice a year run a can of Ring Free by Yamaha or any other manufacturers equivalent product through my engine and always use fuel stabilizer not just for storage.:smile2:
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Jim Seafoam is a stabilizer and it works very efficiently. I have been using it for years and I gave Jeffery the instructions about how to keep the carbon down in a e-mail. When you idle an outboard 2 stroke it needs to be run hard to clean out the carbon before storing.
    There was a lot of money and time spent into the development of seafoam and it works great. I like the fact that it is oil based and won't hurt the engine. I use it in every kind of motor I have from the weed eater on up.

    Jeffery now take that boat out and enjoy it.