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1994 Polaris SLT SBT Motor Problems

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  • 1994 Polaris SLT SBT Motor Problems

    We put a SBT Shortblock motor in a customers ski this April. Everything went smooth on the install. When the customer got the ski to the water, the ski only would turn 4200 RPM's. The customer brought the ski back to the shop for me to go test. We ran the ski, and the ski would never turn over the stated RPM's. We rebuilt the carbs, drained the fuel tank, troubleshot the electrical box etc. After all we did, nothing changed. We removed the motor to find that the woodruff kew holding the flywheel had failed, throwing off the timing. We went to the local Polaris shop, and purched a OEM Polaris woodruff key. The Polaris OEM key was considerable different from the key used by SBT. The Polaris OEM key seemed more beefy, and was tapered on the rounded side unlike the SBT Key. We finally get the motor back together, and started putting the motor back into the ski. While doing so we noticed that the rear crank seal on the motor was sticking out of the case about 1/8" out of the case. I opeted to call SBT, and they gladley sent me a call tag for me to ship off the motor once again.

    After we received the 2nd remanufactured motor, the intall went smooth as uaual. I did not replace the SBT woodruff key account I did not have one on hand. I finally get this ski to the lake, and now the ski will only turn 4900 RPM's. After inspecting the motor and going threw all the hoops, I noticed that the 2nd SBT motor had the rear crank seal sticking out of the case like the 1st motor.

    I have yet to pull the motor again, but I'm afraid that I might have sheered the key again. I did all the testing on the 2nd motor, and there was no apperent back fire. "NOTE" the Polaris flywheel was in good condition, the pto, driveline, and pump were also in good working condition with no apperent vibrations etc. All this was was cleaned, inspected on both motor installs.

    My question is, has anyone had this type of problem? Does SBT have any suggestions on what might have happened? Did SBT rebuild the first motor that they shipped me? Could the problem be in the SBT crank.

    Needless to say I have exhausted myself trying to get this ski back on the water for my customers. My customers have been without a ski since April. I am out countless numbers of hours working on this ski, not to mention driving 85 miles one way to do the testing on the water.

    Can anyone help?
    SAMORA'S SKI PERFORMANCE
    WWW.SSPRACING.COM

  • #2
    Re: 1994 Polaris SLT SBT Motor Problems

    You may not have heard it, but I bet you did have another backfire.


    Woodruff keys are ONLY there for helping you properly align the flywheel during assembly - it doesn't matter if they are tapered, or even look pretty. In actuality, they are not even needed. The ONLY things keeping the flywheel on and in time are the taper and the torque on the end nut/bolt. If your flywheel slipped, it was improperly installed, or some part was defective. The most common mistake I see if someone not knowing about or leaving off the spacer between the nut and crank - only using the nut. This prevents proper torque and allows the flywheel to spin every time. After that happens, you get poor running and backfires - and it only takes one to blow out rear seals, especially on Fuji engines.

    No we never rebuild the same engine, you got a new one off the shelf.
    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: 1994 Polaris SLT SBT Motor Problems

      Bill,

      I do understand that the key is only used for alignment. I aligned the key/fly on both motors, installed the lock washer, and used the correct bolt for the Polaris motor. The flywheel taper seemed to be fine, no apparent gouges, warpage etc. I torqued the flywheel down to 20, 40, then 60' pounds. The specs came from my Clymer Polaris manual. I will have to double check wheat the final torque specs are as I don't have the manual in front of me. I spun the motor, and everything spun fine. I put the PTO coupler, and torqued it, then the fly once more. I also used a Snap-On torque wrench.
      Last edited by sspracing; 08-22-2005, 01:06 AM.
      SAMORA'S SKI PERFORMANCE
      WWW.SSPRACING.COM

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      • #4
        Re: 1994 Polaris SLT SBT Motor Problems

        The spec is 65, 60 is close enough.
        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


        • #5
          Re: 1994 Polaris SLT SBT Motor Problems

          Yea, I checked the book, and we torqued it at 65' #'s. Is there any other thing that might be wrong?
          SAMORA'S SKI PERFORMANCE
          WWW.SSPRACING.COM

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          • #6
            Re: 1994 Polaris SLT SBT Motor Problems

            Nothing I haven't already mentioned.
            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


            • #7
              Re: 1994 Polaris SLT SBT Motor Problems

              The polaris book says to use red loctite on the tapper. The rear seal was cocked sideways when my sbt 780 arrived. Is there a problem with the seals you guys are using? I pushed it back in place before installing the engine. Won't the PTO keep it from coming out? Maybe I should check it tomorrow when it's light out. I thought I had an air leak but it was a high idle and sticky carb linkage.
              He who dies with the most toys Still dies! So have fun with them 1970 SS 396 Chevelle, 86 ATC 250R (RAD valve,K&N, FMF gold series, bandit XC's), 97 XLT600SP (SLP tripple pipes, reverse, EPI clutch kit), 95 SL750 (all the bolt on's) & 96 SLX

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              • #8
                Re: 1994 Polaris SLT SBT Motor Problems

                one of my customers had to twist my arm to put a engine in his polaris lol but i used the SBT engine and its been great . theres only one way for a flywheel to come loose , it was loose . ive had cranks with keyways that could not be used , and never had a flywheel come off { had a PTO come of once } now we dont talk and work at the same time lol .
                it only takes one back fire to blow a seal out .
                PRIDE IN SERVICE<br /> <img src="http://www.sbtontheweb.com/images/forposts/4609/1.jpg" alt=" - " />

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                • #9
                  Re: 1994 Polaris SLT SBT Motor Problems

                  Can you safely push the PTO side crank seal back into the case without splitting the case? The motor seems to run fine with it popped out. I have yet to pull the flywheel to check it. I'm assuming that you have to pull the motor once again to get the fly off. Has anyone did this by removing the fuel cell etc. Let me know.
                  SAMORA'S SKI PERFORMANCE
                  WWW.SSPRACING.COM

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                  • #10
                    Re: 1994 Polaris SLT SBT Motor Problems

                    Originally posted by Polaris_Nut#1
                    The polaris book says to use red loctite on the tapper. The rear seal was cocked sideways when my sbt 780 arrived. Is there a problem with the seals you guys are using? I pushed it back in place before installing the engine. Won't the PTO keep it from coming out? Maybe I should check it tomorrow when it's light out. I thought I had an air leak but it was a high idle and sticky carb linkage.
                    No there is no problem with the seals - but if you had a seal like that when you received the engine, it was an assembly error for sure. Did you call Warranty?
                    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


                    • #11
                      Re: 1994 Polaris SLT SBT Motor Problems

                      Originally posted by sspracing
                      Can you safely push the PTO side crank seal back into the case without splitting the case? The motor seems to run fine with it popped out. I have yet to pull the flywheel to check it. I'm assuming that you have to pull the motor once again to get the fly off. Has anyone did this by removing the fuel cell etc. Let me know.
                      No you can not safely and securely push a seal back in - it should not be out of the groove in the frist place. The reasons it's running is because the inner seal is still holding - but if/when that ones goes, you have an air leak and will immediately burn down the rear cylinder.
                      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


                      • #12
                        Re: 1994 Polaris SLT SBT Motor Problems

                        SBT,

                        I pulled the flywheel from the SBT motor, and the wood ruff key was not sheered. Everything looked clean behind the mag, and the timing mark was centered with the split on the case. NOW, what would cause the rear pto seal pop out on the SBT Motor?
                        SAMORA'S SKI PERFORMANCE
                        WWW.SSPRACING.COM

                        Comment


                        • #13
                          Re: 1994 Polaris SLT SBT Motor Problems

                          Without a backfire it could have been assembly error, or any kind of hydro lock in the rea cylinder, of any liquid. Call in to Warranty and obviously we'll exchange it.
                          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


                          • #14
                            Re: 1994 Polaris SLT SBT Motor Problems

                            Originally posted by Technical Support
                            Without a backfire it could have been assembly error, or any kind of hydro lock in the rea cylinder, of any liquid. Call in to Warranty and obviously we'll exchange it.
                            I must be missing something here. I don't see how you could blow out the rear seal without blowing out the inner as well. Wouldn't the inner have to blow and then the outer? Mine was assembly error. I called today. It will becoming back soon. Thanks. (DON'T FORGET, RED LOCTITE ON THE TAPER)
                            He who dies with the most toys Still dies! So have fun with them 1970 SS 396 Chevelle, 86 ATC 250R (RAD valve,K&N, FMF gold series, bandit XC's), 97 XLT600SP (SLP tripple pipes, reverse, EPI clutch kit), 95 SL750 (all the bolt on's) & 96 SLX

                            Comment


                            • #15
                              Re: 1994 Polaris SLT SBT Motor Problems

                              SBT,

                              This is the second time that this has happened on this ski with the SBT motor. 2 motors that I will have to pull, and reinstall. This is why I'm trying to figure what might be happining. I specifically inspected the 2nd SBT motor's rear seal. The 2nd motor was shipped with the seal in place. Something happened. Might the 2nd motor be the 1st motor that SBT shipped me this April? If so, maybe something is not right with the case or the crank. All in all, I'm just wanting this ski behind me. I want some answers, so maybe the 3rd motor install goes in, and runs correctly.
                              SAMORA'S SKI PERFORMANCE
                              WWW.SSPRACING.COM

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