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  1. #1
    big83bronco's Avatar
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    Question Figure this out!

    Ok so shooter rode my boat this weekend at teh Savannah ride and figured out my boat is spinning the prop liek a mofo out of teh hole, but on top end i cant even turn it to 7000 rpm's. Go figure that one out?

    I know I need more prop on bottom due to spinning out of teh hole, but if I go more prop, I will kill my ski on top end.

    I just dont understand how I can have my cake and eat it to now. I am Soooo close to 70 but just cant get there. The prop I have checked out to a perfect 13/19 repitch off of an original 14/20 pitch with perfect clearance on my wear ring. Pump shoe is good, sealing job is getting a slight bit rough on the edges, but that will be a winter project!

    WHAT GIVES GUYS?


  2. #2
    flyboy's Avatar
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    where's your problem, 13/19... go have it bent to a 14/19, or even a 14/18

  3. #3
    big83bronco's Avatar
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    That is the thing, I should be spinning that prop a whole lot faster on top, but im not. The bottom end isnt really that big of a problem for me, its teh top end. If I have the power to turn it on bottom end, I should have the power to turn it on top too.

  4. #4
    Something has to be slipping. Either the prop is slipping in the water "cavitation" or elsewhere. The boat has more resistance on take off which would make it slip then, but it wouldnt make since with a direct drive to turn more rpms on the bottom than the top unless you have slippage or another issue. I dont think the prop pitch is where the answer lies.

    Is it an efi boat? If so maybe its in your top end setting on the controller. Just a thought.

  5. #5
    big83bronco's Avatar
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    Nope its a carb. boat. Once its on plane it pulls strong up to about 6800 then it slowly gets to 6910 then wont turn anymore. Im thinking it may be a bit rich on top, but teh heat isnt helping RPM's either.

  6. #6
    Thats probably all it is then is the heat. You are correct in the fact that the heat alone will make it run rich on top since the air isnt as dence as when its cool. I wouldnt do anything just yet and try it on a cooler day. On the ATV that I race I have to rejet about every 25 degrees for best results, If I dont the setting for 10 degrees in the winter is a FAT PIG at 100 in the summer
    With a jet ski though its not quite that extreme. your probably just on the upper edge of your jetting.

  7. #7
    2000 GPRXP 4tec shooter98xpl's Avatar
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    Run your ski wide open throttle for about 10 seconds, pull the landyard while running WOT. Pull your plugs and look at them to determine if your rich or not. I would have done this for you, but I was beat Sunday and ready for the long drive home. Either do that or bring your ass up here this weekend, your choice, Heat will reduce your rpms and your speed.
    SHOOTER

  8. #8
    All hail the Chief! fullboogie's Avatar
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    Plug chops are ok, I guess, but I would tune with a good tach (i.e. Pet 2100). That's the best way to jet and make final tuning of the adjusters, in my opinion.

  9. #9
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
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    Hello bis83bronco, You have something wrong and i think it's in the pump shoe. With the compression you are running and the things you have on the ski you should be way over 7000 rpm's with a 13/19. I think your pump shoe is pulling down on high speeds and that would explain why you cavitate with your hole shot. And low rpm's at high speeds because the pump shoe is probally pulling down and causing drag. On my wifes xll 1200 motor i am turning a 05 pump with a dynafly 14/20 setback at 7240 rpm's 90 degress water and air.

  10. #10
    2000 GPRXP 4tec shooter98xpl's Avatar
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    Jim, we have already told him to redo his pump shoe, but he is hard headed. After looking at the pump shoe and the way it was sealed, it definately needs to be redone. Thats why we had told him to bring it up here and we would help him reseal that pump shoe up the right way. But you can only offer, its up to his slack ass to come up here, hahahaha. But he definately needs the pump shoe redone. With the prop he is running which is my 14/20 repitched to a 13/19, I was turning the prop 7150/7180 at 71/72 mph on my ski. I had less compression than he does, so I know he should be able to turn that prop better than I could. Tim bring the ski up this way and we will re-do your pump shoe for you and try another pump liner in place of the one you have and see if that cures the problem. His ski was also rich on the bottom end as well.
    SHOOTER

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