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  1. #1

    slt 780 Whines before take off under load

    Hi Guys,

    I have a slt 780 and was talking with the wife and at the end of last summer on a girls weekend, she said the ski started fine, but when when trying to take off under a Load(With her or one of her friends), she heard a whine and it struggled to take off out of the shoot. But would take off eventually. She said once it took off it ran fine. Just struggles to get out going. She never said anything to me about this before winterizing it. So know I have negative temps again and many feet of snow here in Wisconsin, so it will be a while before we need it, but I would rather start now, with it before it gets time to use it again and it's out of commission. Any ideas?


  2. #2
    are there any guys around Wisconsin that like to work on these as a side job or maybe you guys know of a good mechanic, that I can have them go through the whole machine.

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Whining noise and lack of thrust is probably something in the drive line or the jet pump.

    Pull the jet pump off and inspect. Look at the drive shaft splines on both ends. And the mating splines on the engine and the impeller.

    Inspect the jet pump bearings while you have it out.

    Also look for any signs of debris in the jet pump or damage to the impeller blades or the stator vanes.

    See my signature links for info on how to remove the jet pump and inspect.

  4. #4
    Thanks for the info K447. i will take a look.

  5. #5
    BlueFishCrisis's Avatar
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    In addition to K447's comments, I have experienced this because of an inadequately sealed ride plate / intake grate. This condition allows air into the pump causing a loss of thrust. I experienced it only due to the increased angle due to bow rise when getting up on plane. Once on plane, no issue at all......

  6. #6
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    Where in Wisconsin are you? I may be able to help. Im sure your problem is in the jet pump or drive line. May even a rubber coupler letting go. Doesn't sound like anything severe.

  7. #7
    BryanP Sorry for the late reply. I'm in Appleton. We were so busy last year, I never even got this one in the water. Looking to get something done this spring with it, so we can use it. I also have another Polaris that I need to go through this also

  8. #8
    RLACEMAN's Avatar
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    Sounds like you may have some rope or fishing line wrapped around the driveshaft, or a rock or hard piece of wood stuck between the impeller blades, its very easy to inspect this getting under the ski & looking through the intake grate with a bright light, if you have to remove the pump, this is fairly easy also, it could also be bad bearings in the pump, you have to remove it to check those.

  9. #9
    Okay. Finally got into this. Got the jet pump off with drive shaft. Splines look fine. The rubber washer that goes into the front, by the blades, is all cracked. When removing from the blade section, it just pulled out, very easy. So I need a new rubber washer. Also, the end of the shaft that came out from the engine had no rubber on the end. But there is a rubber washer in the middle section of the shaft. Doesn't make much since to me.

    so do you think, this is my issue?

  10. #10
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    You need to remove the impeller and inspect the pump bearings and seals. I bet a pump rebuild is in order. Make sure you have a good o ring on the drive shaft and bumpers on both ends of the drive shaft

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