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  1. #1

    Low compression on both skis...what to do now?

    Under previous advisement, I have checked the compression on both my skis. A little background first;

    I had problems with my ski after adding non Yamalube oil to the reservoir. Very slow acceleration out of a hole or from the start.. I ordered the d plate and sensor chip. When I removed the cat, it was dislodged into the exhaust. I figured that was the reason for my issue. Yesterday at the lake, it was much improved, however still the acceleration I was used to prior to adding the Pennzoil. Checked compression today, and on the gp1300, I am getting readings of 80ish psi per cylinder. My XLT1200 is showing readings even lower at 70ish per cylinder. I know these are very low compression readings, is it possible I am doing the test wrong? Assuming the test readings are correct, what is my next step to curing my problem/problems? thanks in advance


  2. #2

    Join Date
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    Pennzoil will clog your catalytic converter. Now that the "D" plate is installed, the oil is no longer a part of the equation/problem.

    Did you make sure that you collected all of the pieces of the catalytic converter? Did you also check your water box for any loose parts?

    Have you checked your power valves to see if they cycle FULLY open and closed? When was the last time they were serviced/cleaned?

    What are your RPM's

    I do not even think that you can generate an explosion to generate the power stroke at a cylinder pressure of 70 psig. For this reason I don't think your test readings are accurate, although they might be relative. It is not good that they read so low, but it is good that the cylinders read within 10 psig of each other. Did you use a professional grade compression tester like Proto or Snap-on?

  3. #3

    Join Date
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    First off how old is your compression tester ? Is the o ring good on it ? These are things to figure out. If the compression is within a few lbs i highly suspect the tester to be the issue. Maybe consider getting a new one before anything else. After that go on to other things. Anything stuck in the intake grate area ? is the wear ring looking good ? Any change in anything else ? Fuel, elevation or lake/river?

  4. #4
    Quote Originally Posted by salty View Post
    Did you make sure that you collected all of the pieces of the catalytic converter? Did you also check your water box for any loose parts?

    Yes, removed and inspected water box during install.

    Have you checked your power valves to see if they cycle FULLY open and closed? When was the last time they were serviced/cleaned?

    I am still new at this whole game, I have not inspected the power valves, and do not know how/where to.. Advice?

    What are your RPM's

    I did not record RPM's this last time out on the lake, I will say that the peak rpm's seem to be fine. Going out this weekend, will check rpm's.

    I do not even think that you can generate an explosion to generate the power stroke at a cylinder pressure of 70 psig. For this reason I don't think your test readings are accurate, although they might be relative. It is not good that they read so low, but it is good that the cylinders read within 10 psig of each other. Did you use a professional grade compression tester like Proto or Snap-on?
    Quote Originally Posted by richdash View Post
    First off how old is your compression tester ? Is the o ring good on it ? These are things to figure out. If the compression is within a few lbs i highly suspect the tester to be the issue. Maybe consider getting a new one before anything else.

    The compression tester is brand new, just bought it from Autozone.

    After that go on to other things. Anything stuck in the intake grate area ? is the wear ring looking good ? Any change in anything else ? Fuel, elevation or lake/river?
    Intake grate/wear ring/prop are all in new condition... no changes in fuel or elevation, just the oil used in the ski.

  5. #5
    agsbill's Avatar
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    Are you sure the tester is NEW? AutoZone has a loaner program.....you buy the tester and after you use it you can return for a full refund.

    I checked the compression on my GP1200R using two different testers from AZone and got readings 25psi apart...brand was OEM.

    Bill

  6. #6
    Bought it new in the package, i believe it is "OEM" brand. Is it easy to mess up a compression test? I removed one spark plug, put the tester in, pulled the throttle and started the ski...

  7. #7

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    Goodyear Hater,

    You are gonna catch a little flak now. Did you use the search feature? Many posts regarding correct compression test procedures exist on the site. Read them then re-do test and post new results.

  8. #8
    I did use the search feature, used the steps included in the "HOW TO DO A COMPRESSION TEST", did everything according to the steps besides unplugging the pv, as indicated earlier in the post I do not know where/ how to disconnect/inspect them.

  9. #9

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    You say "started the ski" I assume you mean cranked or did you actually have it running. Compression test should be done with all plugs removed and open throttle. What you are looking for is a difference between cylinders, if they are all the same chances are your gauge is defective.

  10. #10
    i mean cranked, yes..

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