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  1. #1

    2007 Gpr won't run on cyl 3 but will on both cyl 1 and 2

    So my ski won't run on cyl 3 alone has 125 psi compression

    Tried swapping fuel injectors on cyl 2 and 3 to no avail back flushed them aswell

    did a leak down test with good results and couldn't find any leaks with soap eieither

    running out of ideas here and getting sick of it sitting on the trailer

    ski will run on cyl 1 or 2 alone but not 3 and won't get up and go on the water barely can get on plain


  2. #2
    Have you checked your spark to see if its firing? Possible bad Coil or Plug Wire maybe? Or ground inside the ignition box?

  3. #3
    There is spark yes sorry should have mentioned that

  4. #4
    Just curious how do you know it not running? Are you seeing a clean spark plug or is the cylinder coldish when you touch it? What do the other plugs look like are they lean, rich or?

    Trying to run through my thought process here

  5. #5
    If I disconnect the plugs wires on cyl 1 and 2 the ski will not run
    If I have just cyl 1 or 2 plugged in alone then it will run rough but run and I'm told it should run on each cyl by itself not well but should run

  6. #6
    What does the #3 plug look like? Also pull the #3 power valve cover off and see what it looks like. When you switched the injectors did you carry the wiring over with it....could be a wiring issue possibly?

  7. #7
    steach's Avatar
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    Quote Originally Posted by zakre View Post
    If I disconnect the plugs wires on cyl 1 and 2 the ski will not run
    If I have just cyl 1 or 2 plugged in alone then it will run rough but run and I'm told it should run on each cyl by itself not well but should run
    STOP THAT ! it's just not good.

    put in clean fuel, new plugs and go.(hook them ALL up). Check the rpm on the stock gauge at top speed.
    -better yet buy a tiny tach and gps for testing.

    The backfire(s) you produced by doing this have probable broken an intake reed...or six.

  8. #8
    No reeds are broken I just put them all in after changing the crossover plate gasket so reeds are not the issue
    I already have a pet tac aswell and I can't see what rpm I am getting as I can't get the boat above 15mph or so barely even on plane

    It has no get up and go just hits 4000 ish rpm in the water and won't climb any higher

    I didn't switch any wiring around as the injectors are all identical and can be swapped around to any position

    The motor is a 2007 so it doesn't have any power valves

    Motor also has no cat and has a dplate installed

    Thanks

  9. #9
    steach's Avatar
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    What's the compression in all 3 holes ?

    Have you tried new spark plugs ? I chased a gremlin like this WAY too long to find it was a hair crack in the ceramic insulator.
    -I'm not sure how you know which hole is not working but rotating a bad plug will produce the same trouble.

  10. #10
    YudLuz2's Avatar
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    The motor won't run on one cylinder so stop doing it. Hook up all 3 wires with new plugs. Run for one minute on the trailer with water going to your motor. Kill the motor and pull each plug and feel how hot they are to hold. Each one should have the same amount of heat. If one is colder than the other two you have a problem on that cylinder. Either dead plug or not firing correctly if its getting gas.
    Last edited by YudLuz2; 07-20-2013 at 03:39 PM.

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