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  1. #1

    Ultra x250 cavation,new impro impeller

    Have a lot of cavation in hole shot max speed 60 .had a damged impeller had the pump reman by impros with upgraded bearings. They did not tighten the impeller .had local dealer tighten it up ,there is no damage to housing i was very lucky .very disappointing work from impros every one said they are the best ?????.i have sealed the rav grind and plate ,can,t seem to stop the cavation really bad on hole shot,could this be a problem with my shaft seal and how can i diag.thanks andre

  2. #2
    GZA's Avatar
    Join Date
    Sep 2010
    New Zealand
    What is the clearance between the prop and the liner, and are you sure the big seal around the outside of the pump is seated properly?

  3. #3
    RLACEMAN's Avatar
    Join Date
    Aug 2011
    Random Lake WI
    Did you have the pitch of the impeller changed from factory? Is it a factory or Solas impleller? I have had several impellers done by Impros, turns out the one that gives me the best top speed also has cavatation on the hole shot, I have another impeller that is one degree less on the trailing side, has no cavatation on hole shot, but about 1 mph less on top speed, the issue seems to be that the impeller is so effetive that the intake can't supply enough water till the ski is moving about 20 or 25mph. The rubber impeller seal is important, if its damaged even a small amount this will cause cavatation, & I have found about 1 mph speed loss. I would have checked to make sure the impeller was properly tightened before installing, even if they specifically said it was done, an old mechanic friend of mine taught me to double check things like this, but if they said it was done I would let them know it wasn't.

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