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HELP !! Compression test question

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  • HELP !! Compression test question

    Hey folks,
    Just went to look at a 99 xpl that was for sale down the road. I did a
    compression test on the ski and it only had 100 psi in both cylinders. However, I have since found out i did it wrong i.e. didnt hold the throttle wide open during the test. Would this be the difference or is 100 pounds still to far off. May not have the chance to re-run the test since i told the person i did not want the ski.

    thx
    chris

  • #2
    Re: HELP !! Compression test question

    It only makes a couple psi difference. Forget it, if that gauge was accurate.
    SBT Tech Support is here to help with your problems.
    We try to answer each question quickly and accurately.
    Please do not use Private Messaging for Tech Support, use the forums.

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    • #3
      Re: HELP !! Compression test question

      Originally posted by schultztec
      I did a compression test on the ski and it only had 100 psi in both cylinders.
      That is low, however, since both cylinders are equal it is possible that your gauge is not accurate; 140-150 is more like it.

      Originally posted by schultztec
      I have since found out i did it wrong i.e. didnt hold the throttle wide open during the test
      The throttle should not make that much difference on a two stroke engine. By opening the throttle, you allow the engine to get maximum air flow. but a two-stroke with electric start (like all PWC's) will still read reasonably close without opening the throttle.


      Originally posted by schultztec
      Would this be the difference or is 100 pounds still to far off.
      If the reading is actually 100 PSI, the engine is shot...Double check your compression tester before you condemn the engine.
      John Kubiak
      Powersports Technical Training Professional
      Las Vegas, Nevada
      Sea-Doo Tech 13736
      PWC Tech since 1988 (22 years)
      PowerSports since 1976 (34 years)
      NEVER BUY TIRES AT A "BLOW-OUT" SALE
      Please do not use Private Messaging, use the forums.

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      • #4
        Re: HELP !! Compression test question

        yes i actually used 2 different guages with the same results. He also said there was only a few hours on a professional top end job.. Hmmm


        thanks for the info
        chris

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        • #5
          Re: HELP !! Compression test question

          Yeah...a professional WHAT? lol
          SBT Tech Support is here to help with your problems.
          We try to answer each question quickly and accurately.
          Please do not use Private Messaging for Tech Support, use the forums.

          Comment


          • #6
            Re: HELP !! Compression test question

            Kinda bummed, the price was right 2900.00 99 xpl, but the compression was wrong:(

            thanks for the help guys
            chris

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            • #7
              Re: HELP !! Compression test question

              The chances that both clyinders blew 100 psi is slim unless he installed ,025 pistons into a .050 hole.
              Bill O'Neal <br>
              WCM
              <a href="http://www.watercraftmagic.com"

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              • #8
                Re: HELP !! Compression test question

                Bill,
                Could be. Other than that issue, ski is in good shape. Do you think its worth 2900.00 ?? or should i just walk away. Re-building the motor is no big deal for me, I was thinking of making it a winter project and installing your big bore kit..
                thoughts ??

                chris

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                • #9
                  Re: HELP !! Compression test question

                  go take it for a run on the water . see just how good the engine is for his new topend . if it runs great then your guages are wrong , many machine shops cut the cyls way to big or or small and poof . if there cut to big it will sound like hell when running . just never ever buy a ski without running it for a good 30 min or longer run HARD run if your told to take it easy there hiding somthing .

                  ask what pistons were used .
                  PRIDE IN SERVICE<br /> <img src="http://www.sbtontheweb.com/images/forposts/4609/1.jpg" alt=" - " />

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                  • #10
                    Re: HELP !! Compression test question

                    thanks for the info. we did run the ski and it seems to run fine, starts and idles good seems to be fast "i have nothing to compare it to besides my HX and its faster than that" . If i pay 2900.00 and have to put 400.00 into the top end, is 3300.00 a bad price ??

                    thx
                    chris

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                    • #11
                      Re: HELP !! Compression test question

                      Any advice would be appreciated


                      thanks
                      chris

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                      • #12
                        Re: HELP !! Compression test question

                        I sold my 99 XPL the end of last summer for $4000 cash I dont think $2900 is bad as long as it is in good shape and you can rebuild a top end then you should be fine. If you can work on these things yourself then you can save a lot of $$ in labor.
                        Last edited by Dave96GTX; 08-31-2005, 10:28 AM.

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                        • #13
                          Re: HELP !! Compression test question

                          Sounds like a decent deal to me if it is clean.
                          Bill O'Neal <br>
                          WCM
                          <a href="http://www.watercraftmagic.com"

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                          • #14
                            Re: HELP !! Compression test question

                            Thought you guys would appreciate this !!
                            I ended up buying the ski 2800.00 bucks, dropped it in the lake to take for a ride.
                            Seems to run good, accept it would only twist at 6500 rpm. So i figured this was just a symtom of low compression/ tired motor. I figured if it would last the rest of the summer, i'll rebuild her this winter. So after a few tanks of gas were ran through it I noticed if you rode it slow for a while, it would start to load up bad and take a while to clean out. So last week i pulled it out of the water to start messin with it. HERE IS THE GOOD PART ... As I was poking around by the motor a deceided to check power valves, took off the caps and both seemed to be moving free, then I looked at the air tubes that controls them, both tube looked good from each valve to the tee and then the line from the tee went to umm ahhh NO PLACE.. WOW !!this must be a secret tuning setup haha , so after pluging the hose back into the silinoid I deceided to check the carb settings (low speed) carb 1. 3 1/2 turns out. carb 2. 3 turns out. SWEET. It just dont get any better than this. So after setting both carbs to 1 1/2 turns out I put it back in the water and Holy Sh**. It runs like a different ski tons of power accross the board and it now twists around 7000 rpms. I am soooo glad the person I bought this from had it "professionaly rebuilt" :emoticoni

                            PS I also re-checked the compression and now it shows 130 psi, wonder where the other 30 psi came from ???

                            Chris

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                            • #15
                              Re: HELP !! Compression test question

                              Better check those plugs, make sure it's not running lean.. :)



                              Oh, and by the way, I hate you....hehehe

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