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  1. #1

    MSX 150 revs out of control up to 7900 rpms...wont stop

    Hi, I have a 2004 MSX 150 Turbo. I have not used it for a few years (seating under a tarp) but still in awesome shape. I bought a new battery and did an oil change. It started right up. It revs in neutral and in reverse but when I have it in the forward position, it revs out of control up to 7900+rpms but then I turn it off quickly. I re-try it and same thing happens continually. What problem could I be having? Please help


  2. #2
    Banned User
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    I have heard you need to start it in reverse out of the water to prevent that

  3. #3
    I have tried that and it still continues. After, I re-start it in reverse and then If I lightly hit the forward throttle, the rpms will go up and down but if I put it on the full throttle, it will not stop.

  4. #4
    Kosh's Avatar
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    Quote Originally Posted by Rhett View Post
    I have tried that and it still continues. After, I re-start it in reverse and then If I lightly hit the forward throttle, the rpms will go up and down but if I put it on the full throttle, it will not stop.

    Don't panic! This is a known idiosyncrasy.


    Put it in the water and it will settle down, possibly will behave itself out of the water after that but just in case always start it in reverse.


    Enjoy.

  5. #5
    If its out of the water when doing this, I would just adjust ur throttle slightly. From the bit ive been working on these things, it does not take much at all to get the rpms flying. Its not like a car that has so much parasitic drag. Even if the throttle body is open ever so slightly more than it needs to be, it will go crazy. Try disconnecting the throttle cable from the throttle body and then starting it up.

  6. #6
    ripcuda's Avatar
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    Welcome to Green Hulk!

    Yep... as Kosh said... that's "normal" for the MSX 150. When starting it out of the water, leave the reverse lever engaged. Put it in the water and it'll behave normally.

    Oh... and the MSX 110/150 doesn't have a throttle cable actuated throttle body. It's an e-throttle... throttle by wire. The throttle cable from the trigger goes to a PPU unit under the hood where it's converted to an electrical signal for the ETB (electric throttle body).

    Cheers!

  7. #7
    Quote Originally Posted by ripcuda View Post
    Welcome to Green Hulk!

    Yep... as Kosh said... that's "normal" for the MSX 150. When starting it out of the water, leave the reverse lever engaged. Put it in the water and it'll behave normally.

    Oh... and the MSX 110/150 doesn't have a throttle cable actuated throttle body. It's an e-throttle... throttle by wire. The throttle cable from the trigger goes to a PPU unit under the hood where it's converted to an electrical signal for the ETB (electric throttle body).

    Cheers!


    Thanks. I wasbt sure if it was drive by wire. Isnt there an adjustment on the throttle body anyway? I just find that kinda weird a waverunner revs like that ya know.

  8. #8
    ripcuda's Avatar
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    Yeah... the MSX 110/150's behavior of reving up real high when out of the water is pretty odd. It's because it's e-throttle that this happens. On any cable actuated throttle... this couldn't happen. The ECU is trying to maintain a high/cold idle and then any throttle input seems to overwhelm(?) its programming and sends it over the top. It's got to be in the programming... or rather a lack of some sort of fail-safe in the programming. I'd like to have thought Polaris would have gotten it all sorted out in follow-on years with the Weber if they hadn't bailed on the PWC market.

    Cheers!

  9. #9

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    any ideas if the problem still persists in water ?

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