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  1. #1

    New 07 Kawasaki 12F Owner ? about compression test and top sepeed

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    Last edited by TheGrayt1; 10-25-2019 at 10:29 AM.

  2. #2
    RLACEMAN's Avatar
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    You should be seeing a good 5-7 mph more on this ski, at least on the speedo, Its best to check speed with a gps & that should be about 52-53 under ideal conditions. Can you see what the rpms are running at full speed, they should be right at 7000rpms, if its higher then you may have some impeller damage, high oil level can reduce some rpms a little, checking the oil level on the F12 & 15's the rub rail about where the handle bars are & toward the back right before it curves need to be at the exact same height when checking. I'm not sure about the compression test, with an electric fuel pump fuel is being pumped when cranking, this model may have a feature that when you hold the throttle wide open while cranking it will not pump fuel, I think my 15F was like that. Someone else would have to advise you about the ignition if you can pull a fuse for it & still crank the engine.

  3. #3
    Pain is fear leaving your body.... rlovebk's Avatar
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    There are a few reasons why your speed could be lower than it should. #1 is pump - is tolerance correct? Impeller good? Vanes chipped or bent?
    You'll want to get oil level correct. Plugs good? (Always torque and use anti-sieze)
    You can safely check compression by loosening tip sensor and turning it over. This will allow you to turn motor over but no fuel pump. Or you can just do 1 plug at a time. Must be WOT and number not as important as that they be within 10% of each other. I say number not as important as your tester may say 200LB and mine may say 150LB. Balance (+/- 10%) is whats important.
    I always run premium in my 12 and I suggest you do the same. The 12F is a high compression engine and though all sources will say you can run regular I never do. Also ECU # 32 (last 2 digits) can be problematic. Pistons crack. This will push oil out of the engine. Should yours begin to slow and smoke stop it and you should be able to just replace a pistone and walla - it's fixed.
    Good luck. It is a great little ski.

  4. #4
    Quote Originally Posted by rlovebk View Post
    There are a few reasons why your speed could be lower than it should. #1 is pump - is tolerance correct? Impeller good? Vanes chipped or bent?
    You'll want to get oil level correct. Plugs good? (Always torque and use anti-sieze)
    You can safely check compression by loosening tip sensor and turning it over. This will allow you to turn motor over but no fuel pump. Or you can just do 1 plug at a time. Must be WOT and number not as important as that they be within 10% of each other. I say number not as important as your tester may say 200LB and mine may say 150LB. Balance (+/- 10%) is whats important.
    I always run premium in my 12 and I suggest you do the same. The 12F is a high compression engine and though all sources will say you can run regular I never do. Also ECU # 32 (last 2 digits) can be problematic. Pistons crack. This will push oil out of the engine. Should yours begin to slow and smoke stop it and you should be able to just replace a pistone and walla - it's fixed.
    Good luck. It is a great little ski.
    Pardon my ignorance but where is the tip sensor located and I should disconnect it before doing the compression check?

    Also where is the ECU lcoated ont his ski and I will check the number.

  5. #5
    steve45's Avatar
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    I bought some small, round bubble levels to check the oil level on my 4-strokes. Just lay it on top of the head when the boat is in the water. Pull the dipstick out and wipe it off, then push it halfway back into the engine. Lean on the 'Ski to get the bubble level, then quickly push the dipstick in and pull it back out.

    I tried gluing a level on one engine and it self-destructed the first time out. Couldn't take the heat or vibration.

  6. #6
    Here is a pic of the back of the pump if this helps anyone.
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  7. #7
    steve45's Avatar
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    Can't really see a whole lot in the pump picture. Could be damage to the leading edges of the blades, could be too much clearance between the impeller and housing, could be the fins on the stator being damaged, etc.

    The tip over switch is located behind or under the glove box. It's a square black box with a mounting bracket and a 'this side up' label.

  8. #8
    boudin's Avatar
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    Before doing the compression test, from the front of the ski, reach in and pull out the electrical plug from the fuel pump. A pair of needle nose might be needed to squeeze the connector and pull it off. It does not sound like a compression issue, though.

    You said it was a bit rough when you water tested and got 48 mph. I would water test on smooth water first before pulling a pump apart, etc. It might have just been the conditions. 200lb driver, full tank of fuel, rough conditions, you might only see 48 for sure. Also check with a GPS v relying on the speedo.

    I would agree with others to run higher octane in the 12F, especially in hot weather. I've seen several with cracked pistons due to detonation. The older ones did have a fuel curve issue (that can be remedied by a re-flash), but the 07 should be fine. Those were more of the first year 12Fs back in 2003/early 2004.

    -Greg


  9. #9
    Quote Originally Posted by boudin View Post
    Before doing the compression test, from the front of the ski, reach in and pull out the electrical plug from the fuel pump. A pair of needle nose might be needed to squeeze the connector and pull it off. It does not sound like a compression issue, though.

    You said it was a bit rough when you water tested and got 48 mph. I would water test on smooth water first before pulling a pump apart, etc. It might have just been the conditions. 200lb driver, full tank of fuel, rough conditions, you might only see 48 for sure. Also check with a GPS v relying on the speedo.

    I would agree with others to run higher octane in the 12F, especially in hot weather. I've seen several with cracked pistons due to detonation. The older ones did have a fuel curve issue (that can be remedied by a re-flash), but the 07 should be fine. Those were more of the first year 12Fs back in 2003/early 2004.

    -Greg
    Just so I can check where is the computer located on my ski and what number is the updated or good ecu?

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