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  1. #1

    2003 Polaris MSX 140 HO problem

    Just picked up a 2003 Polaris MSX 140 HO. I took it out after replacing the spark plugs with the NGK PZFR6H. It did great but only got up to 50mph according to gauge. After like 5 minutes it only up to 10mph. I took a video of what was happening. Any help would be awesome
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  2. #2
    Click avatar for tech links/info K447's Avatar
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    Welcome.

    Click this link, start reading.
    http://polarispwcknowledge.shorturl....t-things-to-do

    Especially the Ficht section.

    Check cylinder compression, especially if the fuel pressure regulator inside the fuel pump has not been reinforced.

  3. #3
    Myself's Avatar
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    Do as K447 says........he literally wrote the book on this stuff!

    I had a Ficht injected Virage do something very similar. The fuel filter was plugged up and causing low fuel volume. Does it start out fine and repeat the loss of speed after it sits a day?

  4. #4
    I checked the compression on all cylinders. My tool was a cheap one so not sure how accurate it is.
    Rear is 112.5
    Middle is 112.5
    And front is 105
    I don't have a fuel tester yet. Got to see where to get one.
    I just got it so i haven't had time to throw it on the water to try that again.
    The engine will rev but it only goes like 10mph.
    Also if it helps, when i was going fast it took it a little bit to slow down to an idle. Took it like 10 seconds for some reason

  5. #5
    Click avatar for tech links/info K447's Avatar
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    The way to get your watercraft running properly is NOT to ride it on the water. There is a real risk of engine or other damage.

    'Test ride' is something you do after you are already certain you have done the necessary work.
    And after a successful on-trailer test run at the launch ramp.



    Go through the watercraft from end to end, do the recommended checks, maintenance and upgrades.

    Especially the fuel pressure regulator. Does not matter if fuel pressure is normal or very low right now. Regulator mounting must be reinforced, it can literally fall out at any time.

    Engine 'revs' but doesn't go faster than 10 mph - what RPM in the water?
    RPM info can tell us more than just speedometer readings


  6. #6
    What i meant was the guy i bought it from took it out the day i bought it to show me what it was doing.
    I haven't took it out since. It's currently apart. Trying to get the hood area apart so i can try and see if the regulator fell in or not.
    While it was out that one day, when it was only going to 10mph, the rpms only went up to 3000. At idle it was like 2700.
    Hope that helps. Im in no rush to get it on the water as i do want to get this thing properly fixed

  7. #7
    martincom's Avatar
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    Your compression measurements appear low, but all similar, and high enough where it should run OK. So I wouldn't be concerned about that and would dismiss the low reading to the gauge or test environment.

    You can source an affordable fuel pressure gauge here.


    If the engines revs up, without hesitation, but there is no thrust, the pump intake grate is likely clogged with weeds or other debris. You could have pump damage, also. You didn't report any vibration issues and that typically accompanies pump damage. It doesn't cost anything to look down the jet nozzle for damage to the impeller, however.

    As K447 mentioned, you definitely want to immediately re-enforce the fuel pressure regulator (FPR). It is not IF the FPR will fall off, but WHEN. When it falls off, fuel pressure becomes near zero. If at or near full throttle when this occurs, the resulting lean condition will almost instantly burns holes through pistons. It is a bit of a job, but it is one of those once of prevention is worth a pound of cure scenarios.

    See these threads:

    http://greenhulk.net/forums/showthread.php?t=77110


    http://greenhulk.net/forums/showthread.php?t=27510

  8. #8
    martincom's Avatar
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    Trying to get the hood area apart so i can try and see if the regulator fell in or not.
    The three stainless steel, socket head (allen wrench) bolts that hold the steering column support into the hull are notorious for the threads galling (stripping and or locking up). When this occurs, the "T" nuts that are set into a boss in the plastic steering column housing spin. At this point, the simplest thing to do is utilize an electric hand grinder to grind the bolt heads off. They can be replaced with regular stainless hex head bolts, but you will need one socket head bolt, at least, as it serves as the stop for the steering arc.

    See this thread, post #18, for repair details.

  9. #9
    Yup. Mine just spin like you said haha.
    Looks like ill have to grind heads off or get some small need nose pliers.
    For sure going to get to the fuel pressure regulator no matter what.
    Will keep updated as i can. Also going to use my small camera to look at the pistons.

  10. #10
    Here's an update to the msx140. After talking to some and doing some research, my fuel pump needed replacing. It was giving off high amps around 6. Everyone recommended the hfp-378 as the best replacement. It now reads 4.75amps. Still a little high but apparently do-able. Fuel pressure regulator was good too. Was properly secured. Still figuring out the psi and whatnot since mine won't give me a reading.
    Took the jet pump and everything off. The propeller spins freely like normal. I then investigated and found my seal or something is for sure needing replacement. Not sure if that is related to my issue.
    Here's a video of the seal https://drive.google.com/file/d/1lDG...w?usp=drivesdk

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