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  1. #1
    Hueneme Beach Ca.
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    What RPM should I be shooting for?

    I took it out to the river for the first time this season and it just doesn't seem quite right.
    It ran 82.6 down river and 78.x up river. So I guess we can assume it runs right at 80.
    It was running 8150 RPM.
    Would I be better to pitch the prop for a little more RPM ? ( I think it's a 13 - 24 but I actually forgot which prop I have on it right now) I have to pull it off anyway because my wonderful daughter in law idled it into about 6" of water and sucked up a rock.
    The other thing I noticed is that boost was steady but varied from run to run. Sometimes it was only 8# and others it was close to 13#. Not sure what's going on there. Maybe it just needs more RPM to build full boost.


  2. #2
    fx160's Avatar
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    big discrepancy in the boost may mean you have a leak
    either in the bov or just one of the pipes
    i would sort that out before you start looking at adjusting the prop

    kev

  3. #3
    Kristian Keppel Waterholics's Avatar
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    +1 that's why you went 82 then 78. Boost leak. You should check that.

  4. #4
    Hueneme Beach Ca.
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    Let's , for a minute, take the boost issue out of the equation.
    Both the 78 MPH up river run and the 82 MPH down river run were made at a steady 13#
    Both times I was seeing 8150 RPM.
    I just noticed that boost was off a couple of times during the day. I don't think a boost leak would appear and then disappear. Maybe it was a heat thing or something.
    That brings up another question. Has anyone tried the water cooled supercharger housing from R&D? I was thinking of ordering one.
    Thanks.

  5. #5
    Kristian Keppel Waterholics's Avatar
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    Quote Originally Posted by Vettepro View Post
    Let's , for a minute, take the boost issue out of the equation.
    Both the 78 MPH up river run and the 82 MPH down river run were made at a steady 13#
    Both times I was seeing 8150 RPM.
    I just noticed that boost was off a couple of times during the day. I don't think a boost leak would appear and then disappear. Maybe it was a heat thing or something.
    That brings up another question. Has anyone tried the water cooled supercharger housing from R&D? I was thinking of ordering one.
    Thanks.
    It can't be a heat problem either because if it were a heat problem you would constantly be seeing low boost #'s unless you parked up the ski for a long time. I highly doubt this is heat. Heat could neer account for 5#'s of boost pressure. Maybe 1 or even 2 but not 5. How much were your RPM's when you boost was a 8#'s, and how fast were you ?

  6. #6
    Hueneme Beach Ca.
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    Quote Originally Posted by Waterholics View Post
    How much were your RPM's when you boost was a 8#'s, and how fast were you ?
    Didn't check that so I really don't know.
    It's also possible that there's a small leak where the rubber tubing attaches to the gauge or the manifold.
    We'll be checking the whole supercharger, intercooler BOV setup while the prop is out.
    I'm really interested in the prop because it's damaged and needs to be fixed or replaced anyway.
    I checked the box this morning. It's a Skat Trak 13-24 swirl that's in there now.
    Can you repitch the 13-24 to 13-23 after it's repaired? (it's really not hurt very badly)
    It's just that I see guys repitching brand new props and I'm wondering if that's better than just throwing in a new 13-23 and seeing what I think? It wouldn't hurt to have an extra anyway, I guess.

  7. #7

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    Last edited by Gunna; 06-08-2011 at 06:27 PM.

  8. #8
    Hueneme Beach Ca.
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    I talked to Jerry yesterday and he set me up with a 13-23, R&D anti cavitation cone and the Riva Pro adjustable nozzle. We'll see what that does for me.

  9. #9
    Just relax and enjoy the ride. XLT Chad's Avatar
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    Quote Originally Posted by Vettepro View Post
    I talked to Jerry yesterday and he set me up with a 13-23, R&D anti cavitation cone and the Riva Pro adjustable nozzle. We'll see what that does for me.
    That sounds like a NICE setup.

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