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  1. #1

    Polaris slt 780. Is not running wide open.

    I just got this Polaris 97slt 780. It starts up fine. And will idle fine. But when I put in the water it will not go very fast. The throttle is wide open. But will not go fast enough to get on plain. I checked compression and it's fine. Is there a sensor?

    And is there a way to adjust the trim. Because the screen is unreadable. Some of it shows up I can see the clock some times. Any help with this would be greatly appreciated.

  2. #2
    BlueFishCrisis's Avatar
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    Aug 2011
    Medina, Ohio, United States
    Welcome to the Hulk! Lots to read up on here: Http://

    The SLT 780 does have a limp mode function in the CDI. The gray wire from the CDI to the circuit board can be disconnected to check if it is causing a limit. However, this limit will affect the ski on or off the water. In essence, the motor will not rev past ~4k RPM either way.

    If the motor revs free on the trailer, but still bogs down on the water, then you likely have a fuel delivery issue.

    Have the carbs been rebuilt? Fuel pump may need rebuilt? Fuel lines and fuel system should all be updated. These steps are practically mandatory with an old ski.

    What is your location?

    I don't believe the 97 SLT 780 has trim in its stock form. On skis, trim will not affect whether it takes off or not anyway..... Ususally carb and/or fuel related.

    What are your actual compression numbers? "Fine" can be interpreted different ways. In a fresh rebuild, a 780 will have 140 psi in each cylinder, while a 750 in stock form will have 120. What do you have?

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