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  1. #1

    95 sl750

    hey friend new into jet skies v,got a 97 sl750 ,back fire and no high speed throttle under load ,help need ,could it be timing


  2. #2

    back firing sl750

    hey guys i have a 95 polaris sl750 ,rebuilt carbs ,130psi in all 3 cylinder ,wont rev past half throttle ,i m thinking timing ,need tips

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome

    Check the basics. Cylinder compression, test with all spark plugs out, throttle held wide open, strong battery.

    Remove the flame arrestor. Start engine and look for a plume of fuel mist pulsing above one carb. Broken intake reeds will allow the fuel+air mixture to flow backwards through the carburetor.

    You can check timing using a timing light.

    Have a look through my signature links for lots of useful info.

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    BlueFishCrisis's Avatar
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    1st post said backfire, second does not. Is it indeed backfiring? And running? At what speed / condition does it backfire?

  5. #5
    Quote Originally Posted by BlueFishCrisis View Post
    1st post said backfire, second does not. Is it indeed backfiring? And running? At what speed / condition does it backfire?
    it runs and if u crack the throttle it wont revup,130 in all 3 cylinders

  6. #6
    BlueFishCrisis's Avatar
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    1. Is this on the trailer or in the water?
    2. There isn't much timing change that can be done to the Blue Fuji. You will need to pull the flywheel to do it. Was the motor recently rebuilt?
    3. Do you have a tach connected to the motor? At what RPM does it stop?
    4. Is it dying, or does it sound like it is being held back on a limiter?

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by BlueFishCrisis View Post
    1. Is this on the trailer or in the water?
    2. There isn't much timing change that can be done to the Blue Fuji. You will need to pull the flywheel to do it. Was the motor recently rebuilt?
    3. Do you have a tach connected to the motor? At what RPM does it stop?
    4. Is it dying, or does it sound like it is being held back on a limiter?
    If the woodruff key has sheared then the ignition timing can shift around as the flywheel twists on the crank snout.

  8. #8
    its acts at 2500 rpm ,sounds like rev limiter kicking
    I just put this motor together
    timing mark is lined up at the case split
    carbs rebuilt , new 3 outlet pump
    discounted the regulator wire even ,it driving me crazy
    I m a mechanic by trade but I need gods the figure dis one out
    could it be a stator ,I have a 650 motor spare

  9. #9

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by dharmen View Post
    its acts at 2500 rpm ,sounds like rev limiter kicking
    I just put this motor together
    timing mark is lined up at the case split
    carbs rebuilt , new 3 outlet pump
    discounted the regulator wire even ,it driving me crazy
    I m a mechanic by trade but I need gods the figure dis one out
    could it be a stator ,I have a 650 motor spare
    The magneto stator timing mark aligns with the crank case seam during assembly, but the flywheel woodruff key controls the correct timing of the flywheel itself.

    If the flywheel has twisted on the crank end then the engine timing will be incorrect. Did you apply red loctite to the mating surfaces where the flywheel fits onto the crank shaft? Did you use a genuine Polaris woodruff key?

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