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  1. #1

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    Operating RPM - MSX 140

    Really quick. What is operating RPM for 2003 MSX 140? Rev Limiter is at 7,200, so something less than that I assume.


  2. #2
    Lake Mead Bum & BTLS Mark starflight's Avatar
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    I think K447 gets 6800-6900 on flat water on his.

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by starflight View Post
    I think K447 gets 6800-6900 on flat water on his.
    Correct

  4. #4

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    Well isn't that just great. Must be not firing on all 3. It starts out at maybe 6200-6300, then it pulses to 6500-6550. That is it. The hick-up at idle is back as well, so I am going to put my spare EMM in to see if that resolves it. If not, then a pin to pin continuity check on the stator and possible pull the motor and replace. SHIT!


    Hope I didn't smoke my Mag. piston again.

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by Koodat View Post
    ...Must be not firing on all 3. It starts out at maybe 6200-6300, then it pulses to 6500-6550...

    The hick-up at idle is back as well...
    Are you feeling or hearing any pulsing or odd exhaust note at max power, or is it just the MFI RPM display jumping around?

  6. #6

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    You can hear a mis at 4800, then you can identify a surge when it hits at 6300 because the rpm moves up to 6550 and the mph moves up with it. I pulled the injectors to make sure they were shooting gas into the cyl. and the fuel pump is brand new. The TPS has 4 hours on it. I have checked all connections and will go over cables to see if there is freying, but I am pulling toward stator or EMM.

    It all has to do with that stupid pulsing at idle. It drops a cyl. (99% sure it is the mag.) and picks back up. Maybe a bad injector. Just trying to narrow it down.

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by Koodat View Post
    You can hear a mis at 4800, then you can identify a surge when it hits at 6300 because the rpm moves up to 6550 and the mph moves up with it.

    ... I have checked all connections and will go over cables to see if there is fraying, but I am pulling toward stator or EMM.

    It all has to do with that stupid pulsing at idle. It drops a cyl. (99% sure it is the mag.) and picks back up. Maybe a bad injector. Just trying to narrow it down.
    Remind me - have you had the flywheel off this engine?

    As far as I know, these injectors rarely fail. The problem is almost always something else.

    The failure points are;
    TPS (Throttle Position Sensor)
    EMM
    stator
    flywheel magnets
    45 volt capacitor
    wiring and connections
    CPS (Crankcase Position Sensor)
    fuel injectors

    If the magnets come loose from the flywheel, they shift around and can cause weird effects.

    I agree that is it probably the EMM or the stator, but I include loose flywheel magnets in the stator category.

    Do you have another EMM you can try?

    If the stator ohms out OK, and the cranking AC volts are OK, then the best option might be to send it off to DFI Technologies. If they say the EMM is OK, then dive into the stator.

  8. #8

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    Flywheel has been off. I have a spare EMM. I got a procedure from another thread to check the stator. Like a "pin to pin" continuity check. Motor was completely torn apart and re-built and has 4 hours on it. In those 4 hours: Mag. piston and new fuel pump. No errors of MFD and the digital wrench gave it a thumbs up after cylinder re-build and new fuel pump, so I will plug new EMM in and scratch that off 1st.

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