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  1. #1
    BobHouTx's Avatar
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    Polaris 650sl Jet Jon project test run

    Ive been building a Jet Jon boat out of a Polaris 650SL motor. Finally got it on the water yesterday. Took awhile to get good throttle response. Would bog down a die when throttled. Finally got good response and handleing. Did notice a little sputter thought maybe it was cavitation issues. When I slowed down to turn around it died. Wouldnt turn over and appeared to be locked up. Got home and tore into the pistons, they looked good despite oil on the cylinder heads. Im running premix. Thought maybe the problem was in the crank case. The impeller was seized against the wear ring. Why would this seize while riding? Any help before just repkacing would be great.


  2. #2
    MSX 150 guy lives on Mr. GP1800's Avatar
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    Check your pump bearings. They may have failed. If the ski had been used in salt water, the wear ring can swell and pinch the impeller.

  3. #3
    BobHouTx's Avatar
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  4. #4
    MSX 150 guy lives on Mr. GP1800's Avatar
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    That impeller is no good. You should have .020 or less gap between the impeller and wear ring. it looks like you have way more than that.

  5. #5
    RLACEMAN's Avatar
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    One blade looks tight against the pump housing the other side a huge gap, I would say your pump bearings are shot, time to rebuild the pump.

  6. #6
    BobHouTx's Avatar
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    Took the pump apart today. The bearing were shot. I have a spare pump ill install tomorrow.

    What about those cylinder heads? Im running premix. 40:1. I have a 780 I rebuilt and converted to premix and burned a piston.

  7. #7
    BobHouTx's Avatar
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    This is the cleaner cylinder head of the 3. Should I reduce to 50:1
    Last edited by BobHouTx; 07-31-2015 at 06:32 AM. Reason: correction

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