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  1. #1

    Vibration, hesitation, and loss of RPMs..

    Well.. sooner or later my modded ski was bound to give me some sort of problem.

    Last thursday I went on a longer ride. The ski ran strong all day, in fact, I hit my personal best on GPS.
    On the way back in it began hesitating a little bit but still ran strong. On Saturday, It ran ok for a little while and then began vibrating and sputtering when accelerating hard from a dead stop. The problem got progressively worse throughout the course of the day and I stopped riding it. When I got home, I noticed it took on a little water but nothing major. I changed the spark plugs and looked everything over finding nothing out of the ordinary. At this time, I assumed something electrical or ignition related must have gotten wet. I took it out again yesterday (monday) and it was running awful. It was hitting about 7800rpm, hesitating, sputtering, etc- particularly on the low end. It did seem to smooth out a bit at higher speed but again, was only hitting around 7600-7800rpm Id like to get back in the water by Thurs or Saturday at the latest... so its time to troubleshoot. Any ideas?

    The ONLY thing I did out of the ordinary prior to this was use shitty gas from a boat dock. I had a half tank of 93 octane and put in 20 dollars [roughly 6 gallons] of 89oct (because I didnt know until the kid already pumped it).. but that should have still been satisfactory. That load of gas has since been cleared out anyhow and refilled with fresh 93.. there were no metallic flakes on the spark plugs so no signs of detonation..


  2. #2
    JFizzleJR's Avatar
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    I suggest you un-do your intercooler pipe/coupler from the throttle body and blast a WOT run to see if water is coming out of the pipe.

  3. #3
    mrbtd's Avatar
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    Have you checked the S/C slip ?

  4. #4
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    I had a similar experience when my Riva gen1 IC blew the core

  5. #5
    Interesting. Its only been about six hours since I did all these mods...

    I have not looked at anything mechanical at this point. I only looked it over to see what may have gotten wet because there was water in it. I changed the plugs and dried it out. Now its time for a closer inspection.

    I have not checked the slip. Im going to have to research to see how to do it and make that first on the list. That should be done six hours or so after installing a new SC anyhow.

    Ill look into the intercooler as well. You guys are thinking there may be some blockage?

  6. #6
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    Quote Originally Posted by twelvesorbetter View Post
    Interesting. Its only been about six hours since I did all these mods...

    I have not looked at anything mechanical at this point. I only looked it over to see what may have gotten wet because there was water in it. I changed the plugs and dried it out. Now its time for a closer inspection.

    I have not checked the slip. Im going to have to research to see how to do it and make that first on the list. That should be done six hours or so after installing a new SC anyhow.

    Ill look into the intercooler as well. You guys are thinking there may be some blockage?
    Not blockage..Check the IC for water and you can also pressure test it by capping the water exit and pressurizing the core..

  7. #7
    Will do. The very first thing im going to do is inspect the pump and wear ring. 9/10 times vibrations under acceleration are related to cavitation and have something to do with the pump. After that, ill check the IC and then the SC.

    Does anyone have a how-to on checking the slip? I should do that anyway after six hours or so.

  8. #8
    wear ring does not look chewed up... prop is clean.

  9. #9
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    Checking the slip is simple.. Pull your charger, put a rag on the gear and hold with channel locks(if you don't have a gear tool) and use a torque wrench to turn the nut clockwise and adjust the wrench to the proper break then read the wrench

  10. #10
    SC and IC appear to be fine. Im going to ride my XP tomorrow and then pull the pump out on saturday morning for inspection. The issue has to be somewhere in there.

    Im getting ready to go 2Rude so I need to get whatever this hiccup is straightened out before I can move forward.

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