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  1. #1

    780 SLX only bogs in water

    Well, this is the main reason for joining this forum. I've read multiple threads on fixing the problem I am dealing with, but all seem to have vague or different resolutions. My ski is a 1995 (I believe) 780 SLX with the Fuji engine. It has what look to be aftermarket carbs (black, Vortex Ocean Pro air filters on top of black carbs and fuel rails) and it originally would die at WOT in the water when I turned sharply or jumped a wake. I found what I believe was the issue. The electrical box was full of fuel and water (thanks to the previous owner) and was causing things to short out when the mixture made contact with the plug wires or something. Well, I got the box sealed up nice and tight and dry. I put the ski in the water to test it and it would only go to around half speed (I believed it to be in limp mode), but I replaced the fuel filter, lines, and cleaned the petcock, as well as cut the wires from the fuel level sending unit as my MFD is SHOT anyway. Now it revs higher, but it takes it a while to do so when it is in the water. Out of the water, it revs out like a raped ape; but the second it hits the lake, it bogs like crazy and won't rev out until I hit a wake after five minutes of trying to get on plane. It will rev out for a second when I hit a wake, but as soon as it is fully back in the water, it drops RPM just fast enough to stay on plane (feels like about what 1/2 throttle did when it ran perfect except for the dying issue). So now I am at a loss for ideas. Any help would be greatly appreciated.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Have the carburetors been taken apart, internally cleaned, and rebuilt using OEM rebuild kits?

  3. #3
    Quote Originally Posted by K447 View Post
    Have the carburetors been taken apart, internally cleaned, and rebuilt using OEM rebuild kits?
    Do you think that could be it? I've pulled them apart, and everything was still in marvelous shape. Diaphragms, jets and all were clean as a whistle, as well as the small fuel filters. I still blew everything out with carb cleaner and an air compressor.

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Are you sure it is actually running on all three cylinders?

    Do they get equally warm?

  5. #5
    .
    Last edited by BigMeetch; 06-01-2013 at 11:28 PM.

  6. #6
    Quote Originally Posted by K447 View Post
    Are you sure it is actually running on all three cylinders?

    Do they get equally warm?
    They all feel to be about the same temperature after running it.

  7. #7
    Polarisitis loonatik's Avatar
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    Check for air bubbles in fuel line.
    Also, what are your current screw adjuster settings?

  8. #8
    la90043's Avatar
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    i put in a new fuel pump in there with high quality fuel line for that pulse line. that cheap colored fuel line collapses within itself causing fuel starvation.

  9. #9
    BlueFishCrisis's Avatar
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    Quote Originally Posted by loonatik View Post
    Also, what are your current screw adjuster settings?
    +! - When you pulled the carbs apart, assume you removed the high and low speed needles as well and inspected them?? What are they currently set at??

  10. #10
    la90043's Avatar
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    Quote Originally Posted by la90043 View Post
    i put in a new fuel pump in there with high quality fuel line for that pulse line. that cheap colored fuel line collapses within itself causing fuel starvation.

    And then actually everything is a hit and miss when you have no history on your 780. Thats why everything must be gone through and done correctly so that there is a history on it. you start from the tank checking all all valves there. then look at every fuel line no kinks. clamps tight and not biting the hose. inline fuel filter. petcock. fuel pump. pulse line. and then each individual carb. no air leaks or fuel leaks.

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