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  1. #1
    dubl-z's Avatar
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    MSX 140 fuel gauge reading half when empty?

    Can anyone help? I have 53 hours on my ski.. the fuel regulator fell into the gas tank and I was able to fix it for 150 bucks thanks to this awesome site!

    but in doing so when I put it all back together my fuel gauge reads 1/2 a tank when its empty... I took out the fuel pump yet again and thought it was a loose wire... Nope.. I even replace the whole gauge assembly and still reading incorrect... Which leads me to believe I have a short.. but I have checked every wire and every connection... Has anyone else run into this?

    THanks..


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome to the Hulk

    I presume you found the service manuals, which can be downloaded from here.

    How did it cost $150 to fix the fuel pump?

    When the fuel pump was out, was the metal arm for the float bent out of shape?

    Connect an ohm meter to the fuel sender wires. Black and Pink.

    Full tank is 33 ohms, empty tank is 240 ohms. Does your sender provide the correct resistance when the float position is near empty?
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  3. #3
    dubl-z's Avatar
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    Thanks...

    While I had the fuel pump out I thought I better replace it!
    Aswell as re attaching the fuel regulator... I took the entire pump to my auto parts store and they were able to cross it over to a carter p74656m or 71-138s.even know polaris has a patent on it the carter people told us we were on the right track.
    I had to swap out the pump and filters. ..$150

    Thanks for your advice..tommorow I will throw a meter on it and see what it reads....

    I had already printed out the service manual from your advice to somebody else..

    Big Thanks...

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by dubl-z View Post
    ... I took the entire pump to my auto parts store and they were able to cross it over to a carter p74656m or 71-138s...
    I had to swap out the pump and filters...
    What exactly did you end up with?

    The round pleated filter in the bottom of the OEM Polaris fuel pump assembly is a special water repelling filter. It prevents water from getting into the inner pump section from the main fuel tank.
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  5. #5
    dubl-z's Avatar
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    Ive taken a pic of the two fuel pumps side by side..

    It appears you have helped me yet again! Fuel gauge is working properly.. I had bent the float..

    I really appreciate you taking the time to send me pics!

    Question: 1) I have been looking for a 6 degree pump wedge but have only found 5 degree. Do you know of a source for a 6 degree?

    2) What are your thoughts on that chip sold that claims 25 hp?

    3) Ive noticed lately that when my ski gets warmed up I lose top end and thrust taking off.. I just ordered a thermostat and oil filter since ive never serviced them..

    Again.. Thank you.........
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  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by dubl-z View Post
    Ive taken a pic of the two fuel pumps side by side..
    Question: 1) I have been looking for a 6 degree pump wedge but have only found 5 degree. Do you know of a source for a 6 degree?

    2) What are your thoughts on that chip sold that claims 25 hp?

    3) Ive noticed lately that when my ski gets warmed up I lose top end and thrust taking off.. I just ordered a thermostat and oil filter since ive never serviced them...
    1) Six degree wedges - have a look in this thread
    Question for guys running 6* wedge

    There are wedges from two degrees to eight degrees. Some are harder to find than others, but they are out there.

    2) Stay away from that eBay chip power booster thing!

    A few of us are working on ways to boost the Polaris Ficht engines, but these engines are different from everything else out there, so it ain't so easy

    3) Is there a difference between just warmed up and when the engine is hot, in terms of WOT maximum sustained RPM?

    My 2004 MSX 140 runs 6800-6900RPM at WOT, on smooth water. The oil filter just keeps the oil clean that feeds into the engine for lubrication.

    Make sure the oil pump is working properly. There is an index mark on the pump arm, and another on the pump body. Use small mirror and light to see them. Adjust the oil pump cable after adjusting the throttle cable.

    Check the throttle cable for correct slack (adjustment is described in the service manual).

    Also make sure the throttle plates really are opening all the way to the stop when the throttle is fully squeezed. You might want to put some light oil lube (not WD-40) on the throttle shafts and the throttle and oil cables.

    If none of this helps, it is possible the TPS needs replacing, but this is less likely than the other things mentioned.

    Also make sure the fresh air feeds into the hull are not blocked or kinked. These tubes do need to lead into the lower part of the hull to prevent flooding when the hull is capsized.

    You can check if fresh air supply is the problem by riding with the seat off. If the missing RPM and power come back right after you remove the seat (and leave it on the dock), then you know the engine is having trouble breathing.

  7. #7
    dubl-z's Avatar
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    Now hesitating

    K447-

    Took the ski out for the first time today.. Did great.. Well until about an hour into my ride. Now its hesitating bad.. and taking a while to get up to speed.. I checked all my wire connections including battery which the negative was loose.. but that did not take care of my problem. It started all of a sudden..

    Any Ideas?

    I had a new tps installed about 3 hrs ago... ?

    Thanks..

  8. #8
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by K447 View Post
    What exactly did you end up with?
    Fuel pump wise?

    Quote Originally Posted by dubl-z View Post
    ...Took the ski out for the first time today.. Did great.. Well until about an hour into my ride.

    Now its hesitating bad.. and taking a while to get up to speed.. I checked all my wire connections including battery which the negative was loose.. but that did not take care of my problem. It started all of a sudden..

    ..I had a new tps installed about 3 hrs ago...
    Check your fuel pressure.

    Any time the engine is not producing the expected power, do NOT 'push' the engine. These 2-strokes will not put up with under fueling.

    Also check the spark plugs for fouling, and make sure the plug wires are tight.

    Any warning messages or red light on the NGI display?

  9. #9
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    Fuel pump- I just swapped out the pump and the filters.. they were all identical .. into my old fuel pump housing assembly..

    I left my ski in the water.. per your remark of the 2 stroke not liking the underfuel just in case.

    I went to pull it out ot the water and It ran perfect..

    I tested the fuel pressure when I got home 27psi.

    Plugs were not fouled at all.

    No red light or any indicators..

    Is there a coil that can go bad? Im looking at the schematic and it doesnt show one in the electrical?

    Thanks...

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by dubl-z View Post
    ...I went to pull it out ot the water and It ran perfect..

    I tested the fuel pressure when I got home 27psi.

    Plugs were not fouled at all.

    No red light or any indicators..

    Is there a coil that can go bad? I'm looking at the schematic and it doesn't show one in the electrical?...
    So right now, it is running just fine?
    No problems or symptoms at all?

    27 PSI sounds a bit high, but I don't know that you should mess with it.

    If you clamp the return fuel line, does the pressure rise even higher? It should, which indicates that the pressure regulator is flowing fuel, and is not clogged or stuck.

    Not sure what coil you are referring to.

    There are three ignition coils, three spark plug wires, three spark plug caps, and three windings in the stator for powering the EMM, ignition and injectors.

    Might want to make sure the ignition coil grounds are good. They ground through a metal tab under the coil mounting bolts, then to the engine itself.

    Remove the mounting bolts that provide ground, clean the tab and the bolt and the mounting spot on the engine, then reassemble.

    When I cleaned my ignition coils up, I bent the grounding tab on each slightly differently, so the tab would be in direct contact with the engine, not spaced away by the washer. I slipped the washer in on the other side of the tab, and put it back on the engine that way.

    Also clean up the mounting of the ignition coil bracket to the engine.

    Keep in mind that Loctite is an insulator. When you put it on the threads of a bolt, it may prevent the bolt from actually making metal to metal electrical contact. Clean out the old thread lock material with a thread tap and die for the bolt and the hole.
    Last edited by K447; 06-25-2009 at 07:37 PM.

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