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  1. #1

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    slx 785 little power

    I have a problem with my slx... It will start and run but the throttle is limited and cuts out. The pistons/cylinders are fine.. Is there a rpm limiter or something that would be causing this??? The throttle cable is not stuck either... there is a red light that stays on the display also but no there is no readout as to what the problem is.. any help would be greatly appreciated. thx!!


  2. #2
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Most likely going into limp mode. That will limit the engine RPM to 4200, and the red light is a normal indication of this.

    Is the fuel or oil gauge reading low? Only other thing that can cause limp mode is an overheat.

    Once you find the problem, go ahead and remedy it. But in the mean time, you can unplug the grey wire from inside the elec box. That will prevent the CDI from limiting the RPM.

    NOTE: you shouldn't use this as your fix, just a "band aid" for the time being. Find what's the cause and fix it!!!!

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Red flashing light?

    And NO message display?

    Is there any moisture inside your MFD display?

    Do you have a low reading (1/4 tank or less) for either oil or fuel?
    Either one can trigger RPM limit (depending on the model).

    The other trigger for RPM limit is the engine temperature sensor.

    Open the electrical box, and find the Tan wire connection (engine overheat sensor). Unplug the Tan wire, and see if the red lamp goes off.

    If it does, check the Tan wire to the sensor for damage or shorting to the engine. If the wire seems good, then replace the sensor.

    If disconnecting the Tan wire makes no difference, then the problem is with the fuel or oil levels. The fuel level floats are known to get heavy over time, and no longer float properly in the gasoline. If your fuel level is reading lower than the actual tank level, replace the fuel float.

  4. #4

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    Thanks for the info.. I will check it out and see what I find....

  5. #5

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    I opened the electrical box and disconnected the tan wire...The red light stayed on, so I put it back the way it was.... I should mention that the display light is not flashing and stays on all the time with no words in the display.. I disconnected the battery cables and put them back on..I hit the starter button to roll it over and the light did not come on...Also, the fuel and oil levels appeared on the display.. I didn't run the engine long since it was out of the water... I brought it home and may hook up the hose to it tomorrow and do some more troubleshooting. Maybe it is the fuel/oil sensors........

  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Out of the water with a cold engine, you can idle for about 20 seconds without any worries.

    At the moment I don't recall whether the MFD is supposed to flash or just illuminate the red light.

    You can unplug the connector from the back of the MFD. The red light will go out of course, but you check whether the full engine RPM are now available.

    Sometimes if the sealed MFD gets water inside it can go crazy and affect the engine operation.

  7. #7

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    I connected the battery back up to the machine the other night and hooked up the water hose.. I started it and no red light and I could get the rpm's up over 5000.... It ran fine... It shouldn't make a difference in the water when it is under a load should it????????? I am taking them back up north tomorrow for the weekend...

    On a different note. I have some amsoil and if I want to switch over oils can I just pour it in or should I wait till it is low?

  8. #8
    100 MILES OF HEAVEN AND I AM SMACK IN THE MIDDLE KEYZBUM's Avatar
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    Quote Originally Posted by tealducks View Post
    I connected the battery back up to the machine the other night and hooked up the water hose.. I started it and no red light and I could get the rpm's up over 5000.... It ran fine... It shouldn't make a difference in the water when it is under a load should it????????? I am taking them back up north tomorrow for the weekend...

    On a different note. I have some amsoil and if I want to switch over oils can I just pour it in or should I wait till it is low?
    exh. valves opening?

  9. #9
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by tealducks View Post
    ...I started it and no red light and I could get the rpm's up over 5000.... It ran fine...

    It shouldn't make a difference in the water when it is under a load should it?

    On a different note. I have some Amsoil and if I want to switch over oils can I just pour it in or should I wait till it is low?
    It makes a HUGE difference when the impeller has a water load on it. Without the water load, even a half broken engine can get the RPM up.

    If you want to be sure it is working, you must water test it.

    In general, you can mix 2-stroke oils.

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