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RPM drop on take off.

in 2 Stroke Technical Questions 13 years ago

  • Re: RPM drop on take off.

    by » 13 years ago

    My 2 cents worth....those primer bulbs are more trouble than there worth....I had a power loss on take off...traced to this item....I dont have one now,

    Although I see you have a by-pass which is supposed to get around this prob,

    But here in the UK we have had to many fail and totally block the lines.

    Nick.
      
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  • Re: RPM drop on take off.

    by » 13 years ago

    I paid €20 for a Diesel Primer Bulb with the associated fittings at my local Motor Factor shop. It's fitted now for 7 months without a cough.
      
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  • Re: RPM drop on take off.

    by » 13 years ago

    Thanks for all the replies to my problem. I carried out full power checks twice and then removed both carb float chambers.On both occasions I found the rear chamber had very little fuel in and the font one was OK. I removed both carbs and checked all components which were found to match each other OK, but found on the fuel supply pipe to the rear carb, a small chafe mark where it entered the carb. On removal I found a pin hole in the tube obviously allowing air to be drawn in ,particularly when the engine was twisting slightly under full torque. Hopefully that is my problem solved and thanks for everything from all involved. :) :cheer:
      
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  • Re: RPM drop on take off.

    by » 13 years ago

    Hi Kevin,

    What kind of fuel lines are you using? No one should be using the clear plastic fuel lines. These are far more susceptible to cold cracking, UV sun rays, hardening which will split under the vibration and even some kinds will soften with ethanol use. Use something like a fuel injection line the autos and motorcycles use. Replace it every 5 years if you use the fuel injection line and if you do have the clear plastic line I would change it out every 2 years.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
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  • Re: RPM drop on take off.

    by » 13 years ago

    Mmmmm i would not be convinced Kev....the pipe will be under pressure with fuel....so fuel would leak out but I cant see air getting in....whilst the motor is running with it being under pressure,

    I wonder if one of your floats are sticking or something is affecting the needle cut off valve,

    Are the floats set correctly....no kinks in its supply pipe is there....
      
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