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  1. #1

    Any harm in adding a switch to intentionally trigger limp mode?

    Hi all,

    Quick question. I have a 1996 SLT 780 and a 1997 SLTX 1050.

    I boat on a lake that gets very busy on some weekends. Wakes and the washing-machine effect get horrendous, and I'm not into getting pounded to death on the ski.

    Seems the sweet spot for cruising through this mess is about 4000 rpm, around 20mph or so. It is hard for me to hold this RPM/speed for an extended period of time. Seems the power band on these motors comes on right about this rpm and makes it difficult to keep the motors from surging above 4k then back down.

    I was thinking of adding a switch in my fuel float wires so that I could break the circuit to temporarily trigger an empty gauge, which would cause the boat to engage the 4K rpm limiter.

    Is this a bad idea?


  2. #2
    Click avatar for tech links/info K447's Avatar
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    Completely disconnecting the fuel float circuit will cause the MFD to display no fuel level bars at all. I suspect it would not trigger a ‘Low Fuel’ RPM Limit under this condition.

    You can more directly trigger RPM Limiting by grounding the ‘Overheat’ wire (Tan or Gray, varies depending on the module and year). This wire runs into the electrical box from the engine temperature sensor on the water manifold.

    Normally I advise against cutting into the sealed wire harness, but you could rig up a short ‘wire extension’ between the factory wire end and the actual sensor, and then route a tee’d wire from there up to your ‘low speed mode’ switch. When the switch is grounding that sensor wire you will see a HOT warning on the MFD display.

    Note: The RPM limiter works by temporarily killing ignition to one or more cylinders, but it does not affect the fuel mixture going into the engine from the carburetors. So while in RPM limiting mode some percentage of unburned fuel will be going right through the engine and out the exhaust. This will degrade fuel consumption.

  3. #3
    I like Boobs. wetwolf's Avatar
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    Yeah, you might end up fouling plugs as well. Might want to have some on hand just in case.

  4. #4
    Alternately, could you grab an aftermarket throttle wheel and rig up a second thorttle on the other side that is adjusted to only allow 3800-4000 when pulled to the stop?

  5. #5
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    These guys are onto something.

    How about just turning the throttle cable adjustment screw back some? (give it some slack)

  6. #6
    Sooo...how much for the 780? stimpsonjcat's Avatar
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    You're all SLTs...unless you are running with crew just stand up. ;P

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