Jet Trouble
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Jet Trouble

  1. #1
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    Default Jet Trouble

    I am running a Berkeley JE pump on a 79 wisconsin ski boat. It has a AA aluminum impeller. When I am at a stand still and push down the throttle I get up to about 20mph and the the RPMS top out and I only hold that speed. If I back off of the throttle some the pump will seem to catch up so to speak and then I can nail on the throttle and its fine. I checked the packing glad and the seems to be fine. I am under the inpression that I am getting a vacuum leak in the pump. Is this correct and if so were would I start looking to find it.
    Thanks Brian

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  3. #2
    Senior Member wpmxwb's Avatar
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    Sounds like a severe case of cavitation. Did u check to make sure there's nothing in the intake grate? How's the impeller look from the intake grate side or hand hole?

  4. #3
    Senior Member Chop Shop's Avatar
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    If nothing is stuck in the pump or obstructing water flow, then it might just be time for a rebuilt pump.

    Was it fine before, or is it a new to you boat?

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  6. #4
    Senior Member jetboatperformance's Avatar
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    Quote Originally Posted by Problem Child View Post
    I am running a Berkeley JE pump on a 79 wisconsin ski boat. It has a AA aluminum impeller. When I am at a stand still and push down the throttle I get up to about 20mph and the the RPMS top out and I only hold that speed. If I back off of the throttle some the pump will seem to catch up so to speak and then I can nail on the throttle and its fine. I checked the packing glad and the seems to be fine. I am under the inpression that I am getting a vacuum leak in the pump. Is this correct and if so were would I start looking to find it.
    Thanks Brian
    The feeling of "tire spin" you describe does suggest something going on with the jet for sure if no debris , Your E pump should produce crisp thrust on intial take off and plane with relative ease , you may be on track looking for "leaks" The 12JE is typically sealed to the hull with Epoxy (possibly PL5200) , that bond should be complete and solid , the cleanout cover is a potential source of atmospheric leak as well as the packings (you indicate you checked) , check all around the base of the jet casting to hull connection as anywhere the jet can draw air versus water it will If all this is good , It may be time to pull the bowl and take a look its simple and straight forward Tom

  7. #5
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    Default Wood chip or twig....

    I once had a similar experience that turned out to be a wood chip, about the size of my little finger from the last knuckle to the end.... Motor would rev, but the pump would slip....If I eased up to it, I could get maybe 20.......I beached the boat and opened the clean out, and the chip floated out...Problem gone.....
    Ray
    LOUD BOATS SAVE LIVES

  8. #6
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    Sorry for the delay in my responce, I have been tied up with work. This problem has been happening since I started running the boat. I did rebuild the pump about 3 years ago. Everything internally was replaced. I did look at the intake and there seems to be some of the sealing epoxy being used to smooth the transition from boat hull to the intake. There is a small area that as come lose from the hull itself and looks to be creating almost a pocket the would catch in coming water. If a wood chip could cause such issues i would assume this could cause a lot of problems. I will cut this excess away and take it out for a run.Thanks for everyone's help.

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