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  1. #1

    Vx110 full 8000rpm, no cavitation but only 42ish gps

    Just bought a 07 vx110 with only 17hours (damaged trailer years ago) Oil level is good, plugs changed. Ski runs perfect, no noses or cavitation but only goes 42ish gps @ 8000 rpm. Impeller has slight dings in it, but I have never in a decade of playing with these things seen a impeller slow a ski 10 mph with no cavitation. Haven't measured wear ring clearance but looks good, like brand new. Did notice that it went full rpm and speed prior to throttle being wide open, not sure what to make of that with the throttle body, throttle position sensor, ect. Any ideas? I assume it has to be in the pump somewhere as the engine would not pull 8000 if it was damaged but no cavitation at all makes no sense. Please help!


  2. #2
    Formerly Ultra250 TN Aquaholic6801's Avatar
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    Those MR 1 engines run around 10k rpms

  3. #3
    no they run at 8150.

  4. #4
    is the gas fresh?

  5. #5
    is 42 gps?

  6. #6

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    Anything make a home in the exhaust? My 2012 VX turns 8100rpm at 52-53mph gps but will read 5 higher.

  7. #7

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    I have a 2014 vx deluxe and my son has one identical bought the same day.
    They did run neck and neck ,now my son has some slight dings in his impeller and i mean slight . Now i steadily walk away , doesnt take much to effect performance especially when not much performance too start with.


  8. #8
    mwend's Avatar
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    Check the air filter and air box to make sure its all clean; no insects, animals, or oil.
    Now the screws to get in there are a bit of a pain. You can just remove the black rubber
    fitting that connects to the intake manifold and run the waverunner without it connected for testing.
    If it is still at 42 mph then the air intake is not the issue.

  9. #9
    boudin's Avatar
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    If your airbox screws are rusty they can be tough to remove. Unbolt the electrical relay box (2 12mm nuts), unplug it, and move out of the way. You can now easily get to the 2 12mm bolts that hold the airbox in and remove it entirely, even with the fuel line still attached.

    Keep in mind that the airbox bolts on the left side (air intake side) you do not need to unbolt, just the ones on the right side. The airbox will slide right out.

    -Greg

  10. #10
    Did you ever figure out your problem? I have the same symptom (almost exactly) on my 2010 VX.

    Fuel tank was pulled and swabbed clean and fresh gas added with ringfree. Air Filter was fully removed, new plugs, fresh oil, swapped a suspect coil pack and swapped out the pump for a known 50+mph gps pump from Boudin. 45/46GPS. Looks like 8000 rpm but it is actually running 7730 to 7800 max on a LONG 80 mile run using a tiny tach.

    After that run:

    1. Sent injectors into Injector RX. They found 3%, 3%, 5% and FAIL on one injector. Cleaned all and they are all good now. Took it out and No improvment at all in top GPS speed. The last 1/5th of the throttle does nothing.
    2. Tested fuel pressure. 48psi idle and under throttle.
    3. Tested compression and the rear cylinder was way low. 130psi compared to 210 to 220 in all the other 3. This is AFTER an 80 mile run with no signs of missing. Everything sounded great...it was just missing some oomph.

    I'm gonna do a leak-down test next (thanks for the idea Boudin) and fell fairly confident that I will find my missing compression, RPMs and oomph in the fact that one of the exhaust valves are stuck partly open.

    This ski has been sitting around for a couple years by the looks of it when I picked it up. There was a hole burned in the bottom of the water box that the current owner didn't even know about. Looks like a busted ski was passed from person to person for a bit and never did get running.

    How was your compression (without putting any oil in the cylinders?).

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