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Thread: Carb tuning ?

  1. #1

    Carb tuning ?

    I have a 1997 gti 720 single carb that is just giving me a fit when it comes to tuning it. I have replaced all the fuel lines cleaned the tank and selector rebuilt the carbs. The pop off pressure is at 32psi all the holes in the carbs are nice and clean the lows are set at 1 and the highs are set at 1 1/2. Did my first chop and the plug was a little white so i turned the high 1/2 turn and it was still lean. Did my next run with the high turned 1/2 more and its still lean. Where do i need to go next?


  2. #2
    AndinoWatercraft's Avatar
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    What is your compression ? is it standard bore? OEM jetting? The accelerating pump still on ?
    How is the timming ?

  3. #3
    If i knew,...I wouldn't ask sea-one's Avatar
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    Crank seals?

  4. #4
    compression is 150 both cylinders and yes it is standard bore oem jetting 175 pilot and 67.5 no accelerating pump didnt come with one timing is good

  5. #5
    AndinoWatercraft's Avatar
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    Out off water the iddle is ok 3k +/- ? This suggestion is a little dangerous but could help determine if the engine is sucking air from other than the carb. get some carb cleaner, start the engine and carefully spray some to the cases where they come together , some to the rotary valve cover, and the pto side . If the engine revs up it's time to remove and reseal.

    other than the stock fuel filter does it have another one installed?

  6. #6
    does a white plug mean its lean

  7. #7
    AndinoWatercraft's Avatar
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    Yes..!! What size is the neadle valve?

    Not everything is bad. Don't get ypur hopes down. In case you dont find a way to correct it you can always rejet it. What size are the jets installed?

  8. #8
    the main jet is a 175 and the pilot jet is 67.5

  9. #9
    Did the kit come with fuel pump rebuild as well.

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