Carb trouble shooting

Discussion in 'Mechanic and Repair' started by marcs, May 9, 2006.

  1. marcs

    marcs LawnSite Member
    Posts: 10

    The carb on my Kawi fvc420 14hp single, is overflowing fuel. I've disassembled, cleaned and replaced the carb and it still dumps fuel from the overflow tube? The float and needle appear okay, yet I assume the float has a hole or the needle is sticking. Since the float is a special order item, can the hole be repaired? Also, once the repairs are made what's the best way of setting the adjustments on the carb?
  2. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Posts: 1,164

    Test your float by seeing if it floats in a container of gas if it sinks then yes the float is no good, I have never tried to fix a plastic float before so I cant offer much guidance there. But How old is you engine? I have had units that will still leak fuel even with new float and needle because the seat in the carb is whats worn and it is non replaceable you would need a complete carb at that point. :cry: Hope this helps:)
  3. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    Your float doesn't likely have a hole in it unless you find/can hear fuel inside when you shake it. Without looking, I don't believe that carb has a replaceable seat. My guess is that you have a needle that is not seating properly. The needle and seat should be pressure tested. I don't recall what Kaw specs say, but if it will hold 2-4 psi w/o leaking you should be OK. I'm not going to say that you don't have a defective float but I've been working on small engines for some time and have never seen a bad plastic float. If it were cork or brass that would be another can of worms. From what you've said, I would put a new needle in it and pressure test it. As far as adjustments are concerned, the main jet is fixed and you have only an idle screw which should be opened about one and one half turns from a closed position as an initial starting point then adjust as needed.

  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Hold the float between your index finger and thumb and shake it briskly, If there is any fuel inside you will feel it. I wouldn't waist time trying to repair a float, It could make it too heavy and still cause problems. If you feel no fuel inside the float replace the inlet needle valve and hope the seat is in good shape.
    Below is the float adjustment procedure.

    FC420V Float Adjustment.JPG

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