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  1. #1
    RemingtonR-15's Avatar
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    1996 Polaris SL 780 Hitting limiter

    I just rebuilt my 1996 Polaris SL 780. Everything is new including plugs, fuel lines, fuel pump, battery, all new motor from SBT. I took it out today for the first test run and it was running awesome. About 10 mins into the run it hit the 4,000 rpm limiter without any light flashing on the MFD. I had a fuel tank of fuel on the MFD and full oil tank on MFD. I shut it down and took the seat off to check and make sure I wasnt taking on any water and wasnt. I felt the exhaust and I could hold my hand on it but the jugs were a little bit warmer then the exhaust. I put the seat back on and it ran like a dream again for about 5 minutes this time and then hit the limiter again without any light on MFD flashing. So I shut it down and sat on the lake for 10-15 minutes. When i started back up it ran great again for 5 minutes again then hit limiter without any flashing light. Does anybody know what my problem could be?


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    Click avatar for tech links/info K447's Avatar
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    Were the carburetors cleaned internally, rebuilt and adjusted?

    Was the fuel system serviced, new fuel hoses, new filter, new shut off valve?

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  4. #3
    RemingtonR-15's Avatar
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    Yes I rebuilt carbs and fuel pump. Replaced all fuel lines and filters. The only thing on the fuel system thats not new is the shut off valve.

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    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by RemingtonR-15 View Post
    Yes I rebuilt carbs and fuel pump. Replaced all fuel lines and filters. The only thing on the fuel system thats not new is the shut off valve.
    My concern is whether the engine is being affected by the RPM limiter in the CDI or by some other problem that just seems like an RPM limiter.

    There is a Gray or Tan wire coming directly from the CDI module that plugs into the tab terminal board inside the electrical box. If you unplug that single wire from the terminal board, does the problem go away?

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    RemingtonR-15's Avatar
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    I have not tried that. I was concerned it might of been a overheat problem. Could something be bad thats not causing the mdf to flash but still hit the limiter. Im guessing its the limiter because it done this prolly 5-6 times and wouldnt let me go over 4150 but still idled fine. Then after letting it sit a couple mins it would run great again.

  8. #6
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by RemingtonR-15 View Post
    I have not tried that. I was concerned it might of been a overheat problem. Could something be bad thats not causing the mdf to flash but still hit the limiter. Im guessing its the limiter because it done this prolly 5-6 times and wouldnt let me go over 4150 but still idled fine. Then after letting it sit a couple mins it would run great again.
    You can test the HOT warning system. Open the electrical box and find the Tan or Gray terminal group. Use a jumper clip to short the Tan terminals to Black (electrical ground). Wake the display or start the engine. Within a few seconds you should see the HOT warning appear on the display and the red light should flash continuously.

    The overheat sensor on the carburetor engine is a simple on-off sensor that triggers when the exhaust or water tempo exceeds about 160F. When activated the overheat sensor simply grounds the Tan wire. This is the signal to the display and to the CDI module, if your model has a RPM limit mode in the CDI.

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    RemingtonR-15's Avatar
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    Ok i will give that a try and see what happens. Thanks alot K447 for your help.

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    RemingtonR-15's Avatar
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    What is the temp for the thermostat on these and about what temp should you read on your jugs if you shoot them with a laser temp gun?

  12. #9
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by RemingtonR-15 View Post
    What is the temp for the thermostat on these and about what temp should you read on your jugs if you shoot them with a laser temp gun?
    Thermostat opens around 140F on most models, but I think a few had a different temperature
    160F ?

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