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  1. #1

    jet pump/ help me make sense of this - severe cavitation with small stick in jet pump

    we was out on lake today tuning ski after a carb rebuild got everything where i want it , and just cruzing around having a blast then suddenly ski quit propelling when throttling, engine reved but no go .

    however at idle it would cruz about three mph which took me 20 minutes to get back to dock at this rate. dis assembled drive unit looked at shaft really expecting stripped splines , but they looked great. seen a stick stuck in between the housing and blades..jammed..

    question is how did it move at idle but not gain speed at all when throttling up?

    seems if its jammed. ski wouldnt move at all....exhaust maybe?


  2. #2
    forgot to mention removed stick , ran perfect

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by waterlogd View Post
    forgot to mention removed stick , ran perfect
    Even small debris items stuck on the impeller blades can cause severe cavitation which greatly reduces thrust.

  4. #4
    Connecticut CrazyA's Avatar
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    Yup. K is right. I've had the same issue a few times. It gets jammed between the impellers outer edge and liner and creates cavitation severe enough to prevent any real forward thrust at speed.

  5. #5
    thanks i understand about the cavitation,and maybe thats what was going on.this look like a total stoppage of propeller,but then again it may have fell in that position when i shut it down. stick was 3/4 in diameter 2 in. long and had blade 1/2 through it jammed in the middle. anyways good thing its working now

  6. #6
    Rasta Mon Condoms We Be Jammin!!!!! TxVirageTx's Avatar
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    the prop is simply moving or propelling large amounts of water thru suction and compression.the stick creates such turbulence that it aereates the water to the point that the stick spinning rapidly enough creates a pocket of air.the pocket of air overcomes the amount of water passing thru the pump that foward thurst is all but eliminated.the slower the rpm the less aereation caused by the stick.has happened to my wife a fews times by getting into water a little to shallow.even had a white rubber spatula end impale itself on a blade end

  7. #7
    Moderator HiPeRcO's Avatar
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    Had the same thing happen to me on my Kawi STX-15F, and the symptom was the same. Lesson for me - avoid reverse in shallow water

  8. #8
    LaveyT's Avatar
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    Sometimes you can remove the obstruction by moving the back of the ski up and down rapidly while the ski is in the water. Stand in shallow water and grab the back of the ski. some times I can nurse it up to 30 mph (or however fast I can get it) and hit the kill switch. Sometimes that works. Other times if the stick is stuck really good you have to idle back to the trailer. I keep a good flash light and a 3 ft rod in the truck to knock stuff loose once its on the trailer. You can usually knock debris out of the impeller without taking anything apart.
    If you are miles from the ramp this can be a big deal.

  9. #9
    Look like I sucked up a rock. (thought it was deep enough not to suck anything up. Wrong!!)
    Anyways I think I might have damaged the impeller. Can these be rebalanced or are you looking at a new impeller.

    Anyone have one for a 2002 Polaris Virage TX. Are they all the same manufacturer to manufacturer or are they unique to polaris?
    Type, or model number would be helpful.

    What's involved in removing everything to check.
    Still run well, but RPM's were higher at full throtle and not as fast.

    Thanks

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    See my signature links for info on how to remove the jet pump. And find your part number on the impeller

    There is other maintenance you might want to do while you have the jet pump removed.

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