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  1. #1
    Jerry, Jerry, Jerry jerryspringer's Avatar
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    Seadoo 300 compression test numbers

    Hey guys

    gotta a few dramas with my 300 I知 sorting out, whilst doing a few checks I知 gonna do a compression test , what痴 sort of numbers would I expect to see on a 50 hour ski


  2. #2
    Cosmicbrut's Avatar
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    Brand new the compression should be around 150 psi.

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  4. #3

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    As long as the numbers are real close and over/around 120psi I probably wouldn't be to worried about it. My 16PX with about 100hrs is at 120,121,120 last time a checked it. Also the starter is weak. Also it depends how you do it, all plugs in or out, throttle open, warmed up, not warmed up. You get the picture. I kind of know what RPM it should be hitting at different times a year and i have a boost gauge so I have a pretty good idea of where the performance should be.

  5. #4
    Jerry, Jerry, Jerry jerryspringer's Avatar
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    I’m getting 130 130 125 , is that variance acceptable Dino?

  6. #5

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    Quote Originally Posted by jerryspringer View Post
    I知 getting 130 130 125 , is that variance acceptable Dino?
    That doesn't seem crazy to me. Compression isn't the only sign of engine health and lower or higher hours aren't either. If your ambitious could do a leak down and make a better determination. There are specifications for that.

    What is going on with your ski?

  7. #6
    Quote Originally Posted by jerryspringer View Post
    I’m getting 130 130 125 , is that variance acceptable Dino?
    Check each cyliner multiple times. Technique can play a part in the numbers you get!

  8. #7
    Litrebikedoc's Avatar
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    Quote Originally Posted by jerryspringer View Post
    I’m getting 130 130 125 , is that variance acceptable Dino?
    A buddy just checked his 017
    125 , 125 , 122psi cold / dry
    Seems a touch low to me! Anyone have 1630 factory spec / tolerance ?

  9. #8
    Blackhawk36's Avatar
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    As a general rule all compression lowest to highest with less than 10% variance is fine. You are within 3% and that could be attributed to how accurate the gauge is. That is very good. Remember, the compression numbers you are getting are with unboosted air. It would be much higher with the supercharger blowing.

    A GTI 155 will have higher compression than a 300 on a compression test.

  10. #9
    twelve valves's Avatar
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    Hello, I have a 2019 300px with 0hour, I will try to take the compressions this weekend.

  11. #10
    twelve valves's Avatar
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    2019 300px 0hr.
    new battery and regarged,
    cold engine,
    no spark plugs,
    trottle open wide,
    9.5 bar 9.75 bar 9.5 bar.
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