Leaky Float Bowl

Discussion in '2-Stroke Engines' started by Timbone, May 27, 2015.

  1. Timbone

    Timbone Active Member

    I have been bothered in float bowl leakage in recent weeks. Opened it up a time or two, bent the tangs a bit to raise and lower the float level. Still leaking. OK.

    A few days ago, I couldn't give up and when I removed the bolts to the float bowl, the float tang assembly fell to the ground. So I figured that maybe while I was removing and replacing the float bowl I knocked the retaining pin off. OK. So I made a new one out of a finishing nail and reattached the float tangs. Seemed to have good action. Good!

    But the float bowl is still leaking. So I push the float tangs to the closed position (as if it were pushed up by the float) and opened the petcock. The fuel was not stopped! I wonder why.

    Is there some kind of special o-ring or something there that makes a tight seal when the float rises? Yes, the stopper is intact and moves up and down into the fuel inlet. I have no idea where the original pivot pin went so I can't help but wonder if another piece fell out, too.


  2. KCvale

    KCvale Motorized Bicycle Vendor

    Pull the pin out and clean the hole it goes in, sometimes a bit a debris will caught it in there and cause it to leak.
    Timbone likes this.
  3. Timbone

    Timbone Active Member

    Thank you for the advice. I completely broke the carb down and cleaned it up good. There was a bit of gunk in the main jet cylinder.

    But the fuel inlet was very clean. And, once again. I pressed the float mechanism up tight and opened the petcock: the fuel runs freely. It's like an o-ring or washer or something is missing.

    Still the thing was running great today. Lesson: just a tiny bit of gunk in the main jet cylinder can cause a major problem.

    Thanks, KC!
  4. KCvale

    KCvale Motorized Bicycle Vendor

    I had a couple of different CNS carbs that just didn't want to seal well.
    I found a carb rebuild kit and it had a needle with a rubber tip that worked well but that was years ago.
    Best I can do for ya except maybe sharpen the tip of the needle to a nice point.
  5. crassius

    crassius Well-Known Member

    make sure the needle is going in straight - I've also occasionally had to use a drill bit held in my fingers to gently twist in the seat to give it a bit of a polish
  6. KCvale

    KCvale Motorized Bicycle Vendor

    Good point.
    And you have a nail holding the float in place correct?
    Just bend the needle mount to ensure the pin goes in straight.

    And then there is carb angle, is your carb bowl level to the ground?