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Thread: How fast ?

  1. #1

    Join Date
    Mar 2011
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    How fast ?

    Just rebuilt a 98 951 engine and replaced the wear ring. It's revving to about 6900 (measured on the ski meter). How fast should it go by gps on flat salt water ? Everything standard as far as i now


  2. #2
    what ski? if its an xp around 60-62 stock dependent on water conditions/temp/outside temp/elev

  3. #3

    Join Date
    Mar 2011
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    Yes should have mentioned that's it an xp.

    I'm just about to gps mine again but i last time it was 55mph - so i changed the ear ring and it still did 55mph. always been a bit dissapointed with it.

    Engine was stuffed - crank seals and bearings were totally worn out (half the bearings missing !) so i rebuilt it bottom and top ends and it didn't seem a heap better.

    i've never had the speedo above 55mh which seems wrong

    I'll wait for the next gps run

  4. #4
    how much compression in each cyl? was the prop chewed up at all when you did the wear ring? hows the bottom of the hull?

    I hear ya on this one, my xp gps at 53 last summer, wasnt exactly happy

  5. #5

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    after a rebore and new cylinders compression is 135psi on both cylinders - it was a bout the same before the rebuild. Might get 140 psi if i use a use a bigger battery. That's on my gauge and no idea if its accurate. I no 150 is the ideal but after a rebore new cylinders and rings the comnpresion should be as good as it gets right ?

    I measured the volumes of the cylinders at top dead centre and they were in spec with the manual. Engine is revving to about 6950 which is about 350 rpm more than before the build.

    Prop wasn't bad. Yeah bottom of the hull and ride plate are not the best. Planned that as a winter job to get those shiny.

    Made it worse that i had a go on another ski same as mine at christmas time and it was markedly more powerfull and faster all round - even from tickover it practically jumped out the water. Owner knew nothing about skis so might have been standard and might not have. Visually the engine was bog standard.

    Feel i'm missing something - just no idea what. Don't have any mates with similar ski so i have nothing to compare with. Gut feel though 0 it should have more go.

  6. #6
    Quote Originally Posted by southernflip View Post
    I no 150 is the ideal but after a rebore new cylinders and rings the comnpresion should be as good as it gets right ?


    Feel i'm missing something - just no idea what. Don't have any mates with similar ski so i have nothing to compare with. Gut feel though 0 it should have more go.
    951's blow 135 psi, so you are right on

  7. #7
    do you have the trim set in the right spot? Im not sure on the xpl hulls but you probably want it a little above center

  8. #8

    Join Date
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    good point on the vts - since the rebuild the the vts hasn't been working and was set pretty much level so might have to get this fixed now.

  9. #9
    you dont have to replace the vts to get the nozzle where you want it, you can just turn the worm gear behind the vts motor to get it where you want it.

    Although having a working vts is a huge perk

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