PWK 24 carburetor running lean some times

Discussion in 'General Scooter Discussion' started by Karmafield, Jul 26, 2020.

  1. Karmafield

    Karmafield Member

    I have installed PWK 24 on my Derbi Senda and it is running lean after opening throttle.

    Whenever I stand at a red light, it runs really rich. Then I quickly open throttle and runs rich like crazy and doesn't rev high. Smokes everywhere. Then I continue driving, and if I open the throttle while driving, it runs lean and goes to about 10-11k rpm's.

    I have installed a 5mm tap fuel inlet for the 5mm fuel inlet on the carburetor, but still, nothing has worked so far. I am running 140 main jet, and when checking the spark plug after a highway, half is pure light yellow, half is dark gray.

    Also I have installed a repair kit on the carburetor - new float bowl, float valve pin, screws etc.

    The symptoms show, that it is running lean due to the lack of fuel in the fuel bowl, but at the same time I have a brand new fuel tap and parts for the carb.

    I have asked for many 2 stroke forums what the problem might be, but they have no idea at all. I ask local mechanics and they also have no idea.

    Could anyone please help? Thank you!
  2. The Messenger

    The Messenger Active Member

    is it a genuine Keihin (usually dont give problems)

    or is it one of the cheap chinese copys (can be o.k if you get a good one)

    lack of fuel in the float bowl would suggest a fuel delivery problem to the carb it self, rather than the carb is running lean.
  3. Karmafield

    Karmafield Member

    It is a OKO PWK carburetor. Yes, I was really thinking about the fuel delivery problem itstelf. Might just be better off getting a new carburetor, but they are really rare on sale here. Might have to drill a bigger hole in the inlet or something like that. I'm meeting up with a local mechanic soon, he might be able to tell the problem. He wouldn't believe me until he tested it.

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