Announcement

Collapse
No announcement yet.

717 rotary valve gear 1998 gts

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • 717 rotary valve gear 1998 gts

    I have a 717 with a destroyed rotary valve gear. My problem is I can not find why the gear stripped . There is no damage on the valve that would indicate a object stopped the rotation of the valve. What else would cause the failure? There was oil in the chamber. There was brass stuck in the steel crankshaft gear. I have cleaned this gear up and it looks ok. I would like to use the crank and buy the SBT rv shaft and gear only. Is this ok to reuse this crankshaft. Is it ok not finding the cause of the failure? The valve,shaft and bearings do not look overheated.
    Thank you,
    Jeff:emoticonb

  • #2
    Re: 717 rotary valve gear 1998 gts

    No one can guess without good pictures. Attatch some here and we can give you a better answer.
    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


    • #3
      Re: 717 rotary valve gear 1998 gts

      Is it possible that this bad RV shaft is a shaft that came from an engine that had stripped the brass gear, or was this motor a virgin that had never been worked on before this happened?
      Bill O'Neal <br>
      WCM
      <a href="http://www.watercraftmagic.com"

      Comment


      • #4
        Re: 717 rotary valve gear 1998 gts

        Originally posted by Bill O'Neal2
        Is it possible that this bad RV shaft is a shaft that came from an engine that had stripped the brass gear, or was this motor a virgin that had never been worked on before this happened?
        I very certain this motor had never been apart before. Also, the gear on the shaft is jamed up tight to the spring. The end of the shaft that goes into the inner bearing shows wear on one half the diameter.Like It was spining inside the bearing and bent. I don`t know if this was the cause or the result of the damage. Lastly the inner bearing has a grease shield on the side toward the oil. I don`t know if it should be there. I have not pulled that bearing yet.
        Thank you,
        Jeff

        Comment


        • #5
          Re: 717 rotary valve gear 1998 gts

          Originally posted by Technical Support
          No one can guess without good pictures. Attatch some here and we can give you a better answer.
          I`ll see if I can get a camara.
          Thank you,
          Jeff

          Comment


          • #6
            Re: 717 rotary valve gear 1998 gts

            I think what may have happened was the spring has lost the tension that holds it extended and provides full contact of the brass gear with the steel gear on the crankshaft. As the brass gear moves away from the steel gear, it shears the brass gear and then the shaft gets bent. This is not common, but I have seen it a couple of times before. You will know for sure if the new spring hieght is substaintually higher than the old spring hieght when you place them side by side.

            If that is not the case, then the brass gear is just jammed over, compressing the spring and it will not slide back to the proiper position because the shaft is bent.

            Either way, you will need a complete new shaft, seal, spring and gear setup and a new bearing in the case. All brass must be out of the steel gear. It must be completely clean of any brass that may have been smeared into the gear.

            The oil shield on the RV bearing is exactly as it comes from Sea Doo.
            Bill O'Neal <br>
            WCM
            <a href="http://www.watercraftmagic.com"

            Comment


            • #7
              Re: 717 rotary valve gear 1998 gts

              Originally posted by Bill O'Neal2
              I think what may have happened was the spring has lost the tension that holds it extended and provides full contact of the brass gear with the steel gear on the crankshaft. As the brass gear moves away from the steel gear, it shears the brass gear and then the shaft gets bent. This is not common, but I have seen it a couple of times before. You will know for sure if the new spring hieght is substaintually higher than the old spring hieght when you place them side by side.

              If that is not the case, then the brass gear is just jammed over, compressing the spring and it will not slide back to the proiper position because the shaft is bent.

              Either way, you will need a complete new shaft, seal, spring and gear setup and a new bearing in the case. All brass must be out of the steel gear. It must be completely clean of any brass that may have been smeared into the gear.

              The oil shield on the RV bearing is exactly as it comes from Sea Doo.
              I have put the engine back together as stated above. I would like to replace the rotary valve and cover, as it is scored. The sea doo manual said it is a 159 degree? I think it is a 147 degree? This is out of a 1998 gts. Please help. Also could this scoring have cause the rotary gear to strip?
              Thank you,
              Jeff

              Comment


              • #8
                Re: 717 rotary valve gear 1998 gts

                No, scoring does not cause a gear to get stripped, but whatever caused the scoring was probably the cause of the RV gear failure. In other words, someting was loose inside the engine. It got caught in the port and hit by the rotary valve when it came around, That stopped the RV from turning and THAT stripped the gear.
                If you have a Sea Doo with a 718 engine, the Rotary Valve spec is a 159 degree valve, timed at 147 degrees plus or minus 5 degrees opening timing and 65.5 degrees plus or minus 5 degrees closing timing.
                Bill O'Neal <br>
                WCM
                <a href="http://www.watercraftmagic.com"

                Comment


                • #9
                  Re: 717 rotary valve gear 1998 gts

                  Originally posted by Bill O'Neal2
                  No, scoring does not cause a gear to get stripped, but whatever caused the scoring was probably the cause of the RV gear failure. In other words, someting was loose inside the engine. It got caught in the port and hit by the rotary valve when it came around, That stopped the RV from turning and THAT stripped the gear.
                  If you have a Sea Doo with a 718 engine, the Rotary Valve spec is a 159 degree valve, timed at 147 degrees plus or minus 5 degrees opening timing and 65.5 degrees plus or minus 5 degrees closing timing.
                  THANK YOU, NOW I UNDERSTAND, JEFF

                  Comment

                  Working...
                  X