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1998 cierra 2855 - loss of prop power

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    1998 cierra 2855 - loss of prop power

    I just got the above boat last fall and didn't get it on the water much but had it out yesterday and suffered a mechanical issue. I was hoping some of you more experienced boaters could point me in the right direction for troubleshooting. So, I was cruising at about 27 MPH and had a constant RPM at this speed. All of a sudden the boat loses about 75% of propulsion and the engine revs higher as the boat came off plane. It felt like the rear prop dropped off! So I am able to limp it back to the marina at low speed and low RPM (although the engine would still rev high I wasn't about to do so because the power wasn't getting to the props). The outdrive is the Bravo 3 (the one with two counter rotating props).So I get to the marina and both props are on the boat and they both are turning at least at low RPM. Also, since it happened at the marina I noticed a loss of drive oil. It is a good thing I was close to the Marina when it happened. Any ideas?

    #2
    ................
    Originally posted by sprad1970 View Post
    I just got the above boat last fall and didn't get it on the water much but had it out yesterday and suffered a mechanical issue. I was hoping some of you more experienced boaters could point me in the right direction for troubleshooting. So, I was cruising at about 27 MPH and had a constant RPM at this speed. All of a sudden the boat loses about 75% of propulsion and the engine revs higher as the boat came off plane. It felt like the rear prop dropped off! So I am able to limp it back to the marina at low speed and low RPM (although the engine would still rev high I wasn't about to do so because the power wasn't getting to the props). The outdrive is the Alpha 3 (the one with two counter rotating props).
    That would be the Bravo III drive.
    (the A drive is a Dog Clutch drive, and is always a single prop)


    So I get to the marina and both props are on the boat and they both are turning at least at low RPM. Any ideas?
    In some cases this points to a spun propeller hub.
    It could have also been caused by something becoming caught on one of the props.

    I would install your spare props and give it a try.
    If this corrects the issue, you'll want to take the other set in and have them checked!

    Rick E. Gresham, Oregon
    2850 Bounty Sedan Flybridge model
    Twin 280 HP 5.7's w/ Closed Cooling
    Volvo Penta DuoProp Drives
    Kohler 4 CZ Gen Set

    Comment


      #3
      Thanks for the correction Bounty. I am still trying to learn about this darn boat. A little more history that may give some insight. When I got the boat last fall I did take it out a couple of times and had a loss of drive oil (alarm from hell). I had the mercruiser folks at the marina check it out and they put in new seals in the lower unit and new prop seals. Could they have not torqued correctly and would a loose prop hub cause the leaking of drive oil? I have no spare props, at this point, but even if I hit something I don't see how the drive oil would leak out. I can pull a car engine and am somewhat mechanically inclined but will admit I am an outdrive idiot. I am 99.5% certain I hit nothing.

      Comment


        #4
        ...........
        Originally posted by sprad1970 View Post
        Thanks for the correction Bounty. I am still trying to learn about this darn boat. A little more history that may give some insight. When I got the boat last fall I did take it out a couple of times and had a loss of drive oil (alarm from hell). I had the mercruiser folks at the marina check it out and they put in new seals in the lower unit and new prop seals.
        Could they have not torqued correctly and would a loose prop hub cause the leaking of drive oil?
        I would say doubtful, and no!

        I have no spare props, at this point,
        I would want to have spare props on board..... or at least at a location where they could be accessed.

        but even if I hit something I don't see how the drive oil would leak out.
        A severe impact can damage a prop shaft. A bent prop shaft may cause a prop shaft seal to leak.

        I can pull a car engine and am somewhat mechanically inclined but will admit I am an outdrive idiot. I am 99.5% certain I hit nothing.
        Rick E. Gresham, Oregon
        2850 Bounty Sedan Flybridge model
        Twin 280 HP 5.7's w/ Closed Cooling
        Volvo Penta DuoProp Drives
        Kohler 4 CZ Gen Set

        Comment


          #5
          OK. So I will keep bent prop shaft on the list of potentials but I felt no vibration. Rick, what are your thoughts on a worn out engine coupler as a cause?

          Comment


            #6
            Classic spun hub symptoms. Have the leg pressure tested for leak.
            P/C Pete
            Edmonds Yacht Club (Commodore 1993)
            1988 3818 "GLAUBEN”
            Hino EH700 175 Onan MDKD Genset
            1980 Encounter Sunbridge "Misty Blue" (Sold)
            MMSI 367770440
            1972 Chevrolet Nova Frame off Resto-mod in the garage
            Boating on the Salish Sea since 1948

            Comment


              #7
              Blown coupler would be my first though although that usually is accompanied by the smell of burnt rubber.
              Dave
              Edmonds, WA
              "THE FIX"
              '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
              (.030 over-Vortec top end-part closed cooled)
              The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
              Misc. projects thread
              https://www.baylinerownersclub.org/f...56-gctid789773

              Comment


                #8
                No hub to spin on B3 props
                Dave
                Edmonds, WA
                "THE FIX"
                '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
                (.030 over-Vortec top end-part closed cooled)
                The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                Misc. projects thread
                https://www.baylinerownersclub.org/f...56-gctid789773

                Comment


                  #9
                  A lot of good ideas but which one would cause the leaking of the drive oil as well? So far, as Rick surmised, only a bent prop shaft would cause both symptoms. There was no smell of burnt rubber as I changed the oil after I pulled in and would have smelled it. So perhaps it isn't a worn engine coupler.

                  Comment


                    #10
                    Coupler splines could also be the issue. Poor alignment can tear up the splines in the coupler over time. Alignment should be checked every season if the boat is used often.
                    Dave
                    Edmonds, WA
                    "THE FIX"
                    '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
                    (.030 over-Vortec top end-part closed cooled)
                    The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                    Misc. projects thread
                    https://www.baylinerownersclub.org/f...56-gctid789773

                    Comment


                      #11
                      How low was the drive oil reservoir? And was it recently serviced?
                      Dave
                      Edmonds, WA
                      "THE FIX"
                      '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
                      (.030 over-Vortec top end-part closed cooled)
                      The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                      Misc. projects thread
                      https://www.baylinerownersclub.org/f...56-gctid789773

                      Comment


                        #12
                        Originally posted by builderdude View Post
                        How low was the drive oil reservoir? And was it recently serviced?
                        Last fall new prop seals/lower unit seals were replaced. The reservoir was at half by the time I got back to the marina. I then saw the oil in the water coming from the lower unit.

                        Comment


                          #13
                          Originally posted by builderdude View Post
                          No hub to spin on B3 props
                          Good point but from everything I am reading it would be the least likely. My luck it will turn out to be it though.

                          Comment


                            #14
                            Originally posted by sprad1970 View Post

                            Last fall new prop seals/lower unit seals were replaced. The reservoir was at half by the time I got back to the marina. I then saw the oil in the water coming from the lower unit.
                            So no use since the “service”?
                            Recently serviced with new seals and she’s visibly leaking indicates a poorly done job or as Rick suggested a bent shaft. The loss of thrust with increasing rpm could be related but let’s hope it’s coupler related.
                            Id suggest pulling the drive to verify:
                            -where it’s leaking from.
                            -check propshaft runout
                            -check engine alignment.
                            -examine rubber coupler and its internal splines.
                            Dave
                            Edmonds, WA
                            "THE FIX"
                            '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
                            (.030 over-Vortec top end-part closed cooled)
                            The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                            Misc. projects thread
                            https://www.baylinerownersclub.org/f...56-gctid789773

                            Comment


                              #15
                              Originally posted by builderdude View Post
                              So no use since the “service”?
                              Recently serviced with new seals and she’s visibly leaking indicates a poorly done job or as Rick suggested a bent shaft. The loss of thrust with increasing rpm could be related but let’s hope it’s coupler related.
                              Id suggest pulling the drive to verify:
                              -where it’s leaking from.
                              -check propshaft runout
                              -check engine alignment.
                              -examine rubber coupler and its internal splines.
                              I had it out last year twice after the new seals were put in with no issues. When I dock the boat I always check the rear for petrol in the water in addition to walking around the boat.

                              Comment

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