Announcement

Collapse
No announcement yet.

HX 720 ENGINE IGNITION TIMING

Collapse
This topic is closed.
X
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • HX 720 ENGINE IGNITION TIMING

    Bryan,
    I was going over the SBT installation instructions in anticpation of the arrival of my SBT engine.

    Since I have already removed the engine and stripped the parts off the core for return to SBT I would like to know the best way to adjust the pick-up coil timing plate on this engine during re-assembly.

    The 1996 720 Sea-Doo engine DOES NOT use an "MPEM" module or Sea-Doo hand held programmer for ignition timing.
    The OEM manual talks about adjusting the plate using a timing light but recommends 6000 r.p.m. as the engine speed when doing so.

    Since the engine wont be broken in at first, wont this r.p.m. compromise reliability ? Is there a "non-desructive" method to assure proper ignition timing in this scenario ?

    Also, what seems to be very important is the timing mark on the PTO flywheel, and its' proper alignment with the crankshaft. Since this end of the crankshaft is threaded and the PTO//Coupler on the HX is torqued onto the crankshart, wont the position of that PTO timing mark vary in final position from engine to engine in relation to the TDC of the front piston and front charging flywheel and subsequent orientation of the timing plate ?

    This is all a bit confusing to me and the instructions dont address this at all.
    I know the proper advance//retard timing is critical to the engine and dont want to cause a problem through ignorance.

    Also, after I reinstall/time a new Rotary Valve and re-assemble the RV side on the intake assembly and OEM oil system, I plan on taking the engine to a dealer to have it pressure tested, then, when it passes, have them re-install the PTO Coupler and front Charging Flywheel.
    What is the proper test pressure and duration that the engine pressure test must pass ? I want to be very sure I have NO PROBLEMS before re-installing this engine !

    Please advise.
    Dave
    DAVID_HX_XP_RX-DI

  • #2
    You do not need to reset the timing when swapping engines. All you need to do is make sure you bolt the stator back in the correct position - aligning the tick mark on the stator with the tick mark on the case - that sets the base timing.

    You need to hold 5 psi for 3 minutes.

    Comment


    • #3
      Bryan,

      Where exactly are these "Plate and Case" tick marks ?
      Is there a digital picture somewhere in the SBT web site for the 720 engine?

      David
      DAVID_HX_XP_RX-DI

      Comment


      • #4
        Stator pics:
        Attached Files
        Last edited by Technical Support; 07-08-2004, 03:31 PM.

        Comment


        • #5
          O.K. Bryan,

          After rubbing of the beige colored coating in that area of the stator plate I found the tick mark. I needed to use a jewelers eye piece to even see it !
          (but its there,,very minute though)
          The tic mark on the case was a little more obvious but still a very faint impression.

          Strange that the OEM shop manual dosnt even mention these marks. Only someone very familiar with the engine would even know they exist !

          Now,,,,, if I line these marks up, is my timing set,,, or is there any further adjustment needed ?

          David
          DAVID_HX_XP_RX-DI

          Comment


          • #6
            That's all you need to do.

            Just so you know, anytime you have a stator plate with slotted holes like that, that is to adjust the alignment and there will always be a tick mark on them. Sometimes there is a corresponding mark on the case, sometimes it aligns with the case halves themselves (Polaris).

            [ July 11, 2001: Message edited by: Bryan Glynn - SBT Webmaster ]

            Comment


            • #7
              Good Advice...........

              Thanks Again Bryan !

              The digital photo made all the difference.
              Have rebuilt my Carbs. and adjusted jetting and Pop-Off,,, pressure tested (and fixed) fuel delivery system hoses//clamps.

              Now all I need is a visit from Fed-X with my engine....................

              David
              DAVID_HX_XP_RX-DI

              Comment


              • #8
                is this mark on the 580 motors also?

                Comment


                • #9
                  Yes. 580, 650 and 720.

                  Comment


                  • #10
                    Bryan, thanks a lot for this thread... this helped my 650X engine a lot, i know run factory pipe, 44 buckshots, and milled head. runs great! thanks!
                    "Lifes Journey is not to arrive at the grave safely in a well preserved body... but rather SKID IN SIDEWAYS totally worn out shouting... HOLY SH*T WHAT A RIDE!!!"

                    Comment


                    • #11
                      How about seadoo 787 motors?

                      Comment


                      • #12
                        787 has no such adjustment.
                        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


                        • #13
                          If you take the flywheel off and crank out how is the timing set

                          Comment


                          • #14
                            Rusty, electronically with a dealers' programmer.
                            Bill O'Neal WCM
                            <a href="http://www.watercraftmagic.com" target="_blank">www.watercraftmagic.com</a>

                            Comment


                            • #15
                              Re: HX 720 ENGINE IGNITION TIMING

                              Originally posted by Technical Support
                              787 has no such adjustment.
                              about the 787 seadoo xp 1997 how do you set the timing on it

                              Comment

                              Working...
                              X