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  1. #1

    Join Date
    Jul 2009
    WA USA

    MSX 150 No Start Issue. No Spark

    Hi, I'm trying to get an old MSX 150 up and running. It's been sitting for a while. I'll put the key in and it will just crank and crank. I pulled the coils and spark plugs out and cranked it and I was getting no spark off the plugs. Also When I put the key in I don't hear any beeping or clicking noises like my old Seadoo RXP used to do when I plugged in the key. I don't know if these machines do that or not as I'm new to polaris. Thanks.

  2. #2
    Kosh's Avatar
    Join Date
    Sep 2007
    Get that battery up to full charge or substitute it for a known good one. If the voltage drops to 10.8v the ECU will not allow spark or injector pulse. This can happen while cranking on a marginal battery.

  3. #3

    Join Date
    Jul 2009
    WA USA
    Yeah I'm going to check it out on the multi meter while cranking and see. That battery has been sitting dead for a year and I just fully charged it yesterday. It seems to have a lot of juice cranking hooked to the battery charger but to my understanding it needs to be above 10.8 V to activate everything.

  4. #4

    Join Date
    Jul 2009
    WA USA
    Weird. Unplugged it from the charger and I put the key in, heard the Fuel pump prime and it fired up. Can there be any common intermittent ECU or electrical issues with these that would make them not start randomly?

  5. #5
    ripcuda's Avatar
    Join Date
    May 2010
    Newman Lake, WA
    With a stock shutdown module (SIFB)... inserting the lanyard doesn't always do the same thing. I can't explain it any better than the service manual. See the note part.

    System Interface Box (SIFB)
    The primary function of the SIFB is to power--down the ignition system in the event that the lanyard is left inserted
    in the stop switch for more than two minutes. Without the SIFB, the ignition system would remain powered--up
    by the battery, and the battery would completely discharge.
    A secondary function of the SIFB is to convert the reverse switch signal so the ECU can interpret the signal when
    the reverse switch is closed, thereby limiting engine RPM.

    How It works
    The SIFB will disconnect the ECU ignition circuit and go
    into the “sleep” mode in the event that the lanyard is left
    installed in the stop switch for more than two minutes. This
    also holds true whenever the operator pushes the stop button
    momentarily while the engine is running.
    In the event that the operator removes the lanyard from the
    stop switch while the engine is running, the SIFB does
    To power--up the ECU after the SIFB has entered the
    “sleep” mode, the operator must re--insert (if removed) the
    lanyard into the stop switch, and press the start button.

    NOTE: The SIFB remains in the mode in which it
    was put into by the operator’s last action. For example,
    the SIFB will allow the ECU to power--up immediately
    when the lanyard is installed if the operator’s
    last action was removing the lanyard to kill the
    Conversely, if the operator’s last action was leaving
    the lanyard in the stop switch for more than two
    minutes or stopping the engine by pushing the stop
    button, the ECU will not power--up until the SIFB
    “sees” a start signal generated by the operator
    pushing the start button.
    So what your experiencing with hearing the system power up when you insert the lanyard isn't a bug... it's a feature!

    I'd bet the reason it didn't start previously, was as mentioned... weak battery. Be careful jumping or charging the battery while starting it.


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