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  1. #1
    Jimnut's Avatar
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    95 XP800 - won't rev and lack of power

    I recently purchased a 95 XP800 for a price I couldn't pass up. I have had it on the water a few times now trying to troubleshoot why the motor feels as if it has no power at all. Some of the things I have done so far are:

    Replaced grey fuel lines
    Cleaned carbs and internal filters (everything looked very nice inside)
    Cleaned rave valves
    replaced wear ring

    It behaves pretty good. Will idle just fine but terrible throttle response and it never really feels like it opens up and revs like it should. ( I have a 95 SPX with the 657x engine and it is easily twice as fast and exciting to drive). 3/4 - full throttle is required just to get on plane at any decent pace. Again my 650 SPX will walk all over this thing.

    Tonight I removed the water box and then took apart the water regulator and the rubber diaphram was in really bad shape and wasn't sealed at all which effectively rendered it useless. Also noticed that the box had a lot of water in it (few inches deep when you looked down the exit port. I've read up on how the box needs to clear itself out to reach max RPM's and obviously that isn't helping the situation but It doesn't seem like that would cause all of my issue.

    I have also done a compression check and the readings are 150 (mag) and 155 (pto). The motor was rebuilt 4 years ago.

    Sorry for the long post but I am running out of ideas on what is holding back the RPM's and the power I know this machine is capable of. Any suggestions on what I should check out next?


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  2. #2
    >> Tonight I removed the water box and then took apart the water regulator and the rubber diaphram was in really bad shape and wasn't sealed at all which effectively rendered it useless. <<

    That would be a bad issue for what you are describing... Replace the water regulator...

  3. #3
    Joe Stang's Avatar
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    Is the baffle busted inside the box as well?

  4. #4
    Jimnut's Avatar
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    There was nothing rattling around in the box when I had it out so I'm assuming its fine. I also just swapped rectifiers with a known good one from a 96 xp and while it seemed to run better I think it was due to fixing the water regulator more than anything. I'm getting to a loss on this thing. I am about to rebuild the carbs just to rule them out but they appear to be in great shape.

    Anyone have any other idea's?

  5. #5
    you say you cleaned the carbs but did you check your pop off pressure if so what was it and did you check the needle and seat for leaks i did the same thing cleaned the carbs but didnt check my pop off pressure and the ski had no balls at all ran get at idle and putting around but no speed on the top end. i ended up taking the carbs off and taking them to all pro water sports local shop to have the pop off pressure checked and it was wrong lol put the carbs back on and away i went ski runs 58 ish all day long now .

  6. #6
    Jimnut's Avatar
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    I did not check the pop-off pressure when I had them apart. That sounds like the next thing I need to do.

  7. #7
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    yeah..that carb spring is at least 18 years old.... those little 787 xp's scare me..a whole lot of power in a sleeper hull. Little tight on the inside however...

  8. #8
    i think if you get those carbs done that you will be alright good luck and post bacck if it fixes the problem

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