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  1. #1

    SLT 780 problems

    I have a 1996 SLT 780 that I am having an issue with.

    On the trailer it starts up and works perfectly. Drop it in the water it works great for the first 3-5 minutes. After that time the engine just idles down to the point where you can't plain out. Let the ski sit for 5-10 minutes it will then run just fine again for 3-5 minutes.

    I am wondering if the heat sensor is enabling the limp mode on the 96 slt 780?

    If so what do I need to do to fix this?

    Does my assesment sound correct?

    Would this be the part I need to replace? SWITCH,THERMO (825C)

    Any help would be appreciated.

    Thanks,

    Yochichi


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Does the maximum RPM suddenly drop to a lower level, and just stay there?

    Or does the engine gradually reduce the maximum RPM it can run at?

  3. #3
    It gradually reduces the max rpms it runs at.

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by yochichi View Post
    It gradually reduces the max rpms it runs at.
    That does not sound like an RPM limiter issue. The RPM limiter is either engaged, or not, and it limits to a specific RPM right away when it kicks in.

    I would be thinking it is a fuel system or carburetor issue, or possibly an ignition issue.

    When it happens next, stop the engine, and crack open the fuel filler cap. See if there is a partial vacuum inside the tank. Once the pressure has relieved, tighten the gas cap, see if it then starts running properly again.

    If it does work OK after cracking open the gas cap, then replace the fuel tank venting check valves. There are two - replace them both.
    Last edited by K447; 07-09-2010 at 02:02 PM.

  5. #5
    Ok I will give that a try tonight. Thanks for your help.

  6. #6
    This problem turned out to be a brass filter on the exhaust cooling system being plugged. The engine was just overheating.

    Cleaned out the filter and the ski runs fine now. Thanks for the suggestions.

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by yochichi View Post
    It gradually reduces the max rpms it runs at.
    Quote Originally Posted by yochichi View Post
    This problem turned out to be a brass filter on the exhaust cooling system being plugged. The engine was just overheating.

    Cleaned out the filter and the ski runs fine now...
    So the maximum engine RPM was suddenly becoming limited to a fixed level when the engine became too hot - correct?

    Not a gradual RPM reduction as you continued riding...

    What about the MFD display? Was it working? Red warning lamp or HOT message?

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