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Thread: 1998 slt 780

  1. #1

    1998 slt 780

    ski starts fine idles fine runs fine up to 4150 rpms then it begins to stumble it will smooth out if i bring it back down below 4150.i have replaced plugs air filter fuel seperator assembly and drained all fuel replaced with fresh also it runs premix what to do next ???


  2. #2
    Tony's Avatar
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    Does it feel like it's hitting the rev limiter? Any letters or red lights flashing on the MFD? Double check your model and/or year, they didn't make a SLT780 in 1998.

  3. #3
    maybe 96 yes lopwr and other lights flashing but they have been like that since i bought it last year and it ran well started doing this about a month ago when a friend was riding

  4. #4
    la90043's Avatar
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    you have to find out what is making the lights flash. the motor protects itself from damage by not letting it rev to its maxiumum potential. thats why it only revs to 4100

  5. #5
    when this first started a friend was riding in a very weedy area at low speed i see nothing in impeller is it possible something clogging internal cooling system and how would i check ???

  6. #6
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    This is just a TEST, not a fix.

    Open the elec box and remove the grey wire from the board. See if the ski runs good again.

    If it does, you're in limp mode and something is wrong. That's why the engine is limited.

  7. #7
    la90043's Avatar
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    When you're on the lake/river/sea and the boat will not go past 4100 rpm take the seat off and touch the heads/cylinders/exhaust. Are they untouchable? will water sizzle on it? does the motor seem way too hot to the touch? you should be able to place the palm of your hand on all these items for a short period of time at least........................

    You can have a over heating problem. clogged passage. clogged exhaust pipe screen.

    be careful. the motor is telling you that something is wrong and you can ruin the motor. seize it.

  8. #8
    la90043's Avatar
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    take out and clean out the fitting screen on the exhaust.

    its number 9 here http://fiche.worldofpowersports.com/...pe=13&A=24&B=5

    ALSO CHECK THE INLET SCREEN AT THE JET PUMP

    ALSO CHECK THE THERMOSTAT AND POP OFF VALVE IN THE COOLING RAIL
    Last edited by la90043; 08-11-2009 at 02:30 PM. Reason: SPELLING

  9. #9
    pulled cooling rail ? yesterday was clear. pulled thing on end of it. was clear.i pulled hose off T that goes to back and started with hose and got good solid stream.pulled hose at rear that goes through hull put garden hose on and got good spray out nozzle.pulled hose off nipple that diagram says is filter and got needle size stream out. as to wiring did not find grey wire found light blue.found tan black red pink so i unpluged all at back of display.will fill with fuel add 2 bottles of seafoam and take it out saturday and see if i solved anything will check heat of engine while riding.let u know what happens.

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Gray RPM limiter wire is inside electrical box, not behind display.

    Does your MFD display work?

    Any warning message along with the red light?
    There is only one red light, the details show up on the display itself.

    HOT means the sensor is indicating overheat.

    Low Oil or Low Fuel are self explanatory

    LoPwr means the MFD is detecting very low battery voltage. Either the wiring for the MFD has a problem, the battery is failing, or the charging system has a problem.

    Sometimes an MFD will show LoPwr when there isn't actually any problem. In that case, the MFD can be reset, which often fixes the problem.

    Multi-Function Display (MFD)

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