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Thread: holeshot?

  1. #1

    holeshot?

    I finally got a chance to get out today for about 20 minutes to get some RPM readings from the 14/20 for the repitch.

    While I was out I noticed a few things.
    1. anything over half throttle from a dead stop it cavitates like a MOFO.
    2. If it does happen to hook up at like 3-4mph it jumps up enough to unload the prop and then cavitates.
    3. when accelerating WOT from say 20 mph the ski porpoises about five or six times before it settles down (then its pretty solid) but it is annoying having to lean over the bars to settle it.

    I know the 800 grate, 87mm nozzle, and under pitched prop all lead to cavitation but do you guys think its bad enough that just a quick blip of the throttle should cavitate? The pump and transom plate seal looked great after the ride so thats not it.

    When you guys holeshot, do you trim the nose down until your underway then bring it back up to keep it from jumping out of the water enough to become unhooked?

    I know I could shim the tabs to loose the porpoise but how are guys riding without tabs (assuming it would be even worse then)?


  2. #2
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    Quote Originally Posted by porksword View Post
    I finally got a chance to get out today for about 20 minutes to get some RPM readings from the 14/20 for the repitch.

    While I was out I noticed a few things.
    1. anything over half throttle from a dead stop it cavitates like a MOFO.
    2. If it does happen to hook up at like 3-4mph it jumps up enough to unload the prop and then cavitates.
    3. when accelerating WOT from say 20 mph the ski porpoises about five or six times before it settles down (then its pretty solid) but it is annoying having to lean over the bars to settle it.

    I know the 800 grate, 87mm nozzle, and under pitched prop all lead to cavitation but do you guys think its bad enough that just a quick blip of the throttle should cavitate? The pump and transom plate seal looked great after the ride so thats not it.

    When you guys holeshot, do you trim the nose down until your underway then bring it back up to keep it from jumping out of the water enough to become unhooked?

    I know I could shim the tabs to loose the porpoise but how are guys riding without tabs (assuming it would be even worse then)?

    hippity-hoppity...

    I always trimmed down and leaned forward, took off, and trimmed up while walking backwards into a crouching position...

  3. #3
    MR. SCOVILLE UNIT SUCKMYWAKE's Avatar
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    While I was out I noticed a few things.
    1. anything over half throttle from a dead stop it cavitates like a MOFO.
    2. If it does happen to hook up at like 3-4mph it jumps up enough to unload the prop and then cavitates.
    3. when accelerating WOT from say 20 mph the ski porpoises about five or six times before it settles down (then its pretty solid) but it is annoying having to lean over the bars to settle it.


    ah sounds so familiar. is this the new um setup???

  4. #4

    launch control

    ? I have an o5 and the electronics are suppose to keep the rpms/fuel right at the optimum sweet spot to keep the nose up/hop from happening. I've got the 1300 grate and IR's plate and have never had a problem getting out of the hole.
    that being said, when I install the Jet works this week , it may change everything.

  5. #5

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    The 800 grate is not meant to holeshot. It will cavitate even on a stock ski.

  6. #6
    Actually this is the standard setup. I was planning on trying the "new" setup after the repitch. I think im going to slap on the 1200 grate and 85mm nozzle to see if there is a big diference today.

    mxvet, when you install the jetworks you will probably see more cavitation because the low end bog will be decreased.
    before adding the 150 psi head, timing key, 800 grate, VF reeds, jetworks, and some other air mods. I could pin the throttle at a dead stop with the 14/20 and have zero cavitation.

  7. #7
    Quote Originally Posted by Ronn25 View Post
    The 800 grate is not meant to holeshot. It will cavitate even on a stock ski.
    So thats probably the big part of the problem then. Thanks.

  8. #8

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    Yes, the 1200 will solve your cavitation problems, if it doesn't then you have other problems. At 20mph, your barely on plane, if your running an angled plate it will want to lift the front out on the water if you nail it at that speed. Now at 35-40mph it should accelerate nicely without triming down.

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