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    shafts turning

    Today I was at the boat doing a routine check. While the engine room hatches were up, I decided to start the motors and let things run awhile and create some heat. With the twin Hinos idling and in neutral, I noticed that both shafts were rotating. I double checked and kicked each motor in and out of gear while tied up and returned the shifters to neutral. Both shafts continued to spin. Does this happen on other's boats too? Is there some sort of transmission adjustment that would solve this? Thanks.

    Keith
    1986 3270, twin 110 Hinos
    Olympia, WA

    #2
    Pretty normal
    1989 3888
    Nobody gets out alive.

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      #3
      Pretty well normal. It's just the fluid being circulated. Mine rotate with the flow of the river.
      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

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        #4
        Weird.

        My shafts don't spin if I'm not in gear. 38 with 175 Hinos

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          #5
          Maybe you have newer cutlass bearings than the OP
          Stan
          2001 Bayliner 4788
          Underhulls
          Bow & Stern Thrusters
          Hydronic heater
          330 Cummins

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            #6
            Mine do not spin in neutral...even out of the water while winterizing...
            1988 3888 "Liberty"
            Twin Cummins 6BT's 210hp
            Onan 8.0
            Boating Raritan Bay

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              #7
              My cutlass bearings are ancient.

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                #8
                Here is something to think about. If shafts are well aligned they ought to spin freely. If the shafts do spin freely it would not take much force by fluids circulating in the trans to cause them to turn in neutral. One might wonder if the shafts are not turning somewhat in neutral if the shaft alignment might be off? On larger boats all bets are off with the boat on the hard as hull flex can cause alignment to be off.
                Tony Bacon,
                Washougal, WA
                Caspian
                1997 3788 Twin Cummins 250hp

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                  #9
                  Any current in your moorage?
                  1989 26' then 1994 32' now 2001 39'

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                    #10
                    Shafts should only turn in neutral if there is significant current (2+Kn), i.e they are back driven by the props.

                    There are no torque converters in these transmission, only two clutch packs that are activated/compressed via oil pressure depending on actuator position, either forward or reverse. If the shaft is turning without current, one of the clutches is not releasing completely. Either the clutch pack is distorted (overheat etc) or the spool valve/actuator that directs oil pressure needs to be rebuilt.

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                      #11
                      Originally posted by gsholz View Post
                      Shafts should only turn in neutral if there is significant current (2+Kn), i.e they are back driven by the props.

                      There are no torque converters in these transmission, only two clutch packs that are activated/compressed via oil pressure depending on actuator position, either forward or reverse. If the shaft is turning without current, one of the clutches is not releasing completely. Either the clutch pack is distorted (overheat etc) or the spool valve/actuator that directs oil pressure needs to be rebuilt.
                      Must be what is happening with mine. There is no significant current where I am moored and it only happens with the motors running. Will this cause future problems?
                      Keith
                      1986 3270, twin 110 Hinos
                      Olympia, WA

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                        #12
                        Kieth, That is quite common , noticed quite a few Velvet Drive's do that as well. Quite often it will do it when first started up, then quits as the oil warms up. Haven't heard of it being an issue.
                        1987 3218 135 hp Hino's
                        Bremerton Yacht Club
                        '07 Guzzi Norge

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                          #13
                          I'd make sure your actuator is fully in the center idle position by detaching it temporarily from the shift cable. If that does not fix it, I'd change the transmission oil, replace the filter or clean the filter screen. Make sure you have the appropriate oil weight. This may not fix it but at least you have clean oil in there. Eventually, the clutch packs might have to be replaced.

                          Recently I looked at a boat with 8V92s and ZF gears. When the broker started the port engine, the boat surged forward against the dock lines due to the same issue. The broker also insisted that it was not uncommon. But it turned me off. No way I'd want to maneuver a 65' boat in a marina with one gear stuck in forward until it "warmed" up.

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                            #14
                            When I rebuilt my Velvet drives the shafts turned while in neutral for most of one season, following season they did not spin.
                            Does it only happen when cold?
                            Pat says: DO-IT-RIGHT THE FIRST TIME!

                            Bayliner 3870 "ALASKA33)
                            Twin 350 GM power
                            Located in Seward, AK
                            Retired marine surveyor

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                              #15
                              Originally posted by boatworkfl View Post
                              When I rebuilt my Velvet drives the shafts turned while in neutral for most of one season, following season they did not spin.
                              Does it only happen when cold?
                              Great suggestions. Now I am curious about the temperature thing. Guess I will have to take her out on a run and check for the shaft spin in neutral after everything is warmed up. It seems relatively minor and I don't notice it being a problem while idling in and out of gear getting into/out of my slip. Thanks!
                              Keith
                              1986 3270, twin 110 Hinos
                              Olympia, WA

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