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Proper friction on 38 drive shafts-gctid357538

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    Proper friction on 38 drive shafts-gctid357538

    When I hauled out last fall I checked a lot of things that I couldn't while in the water. I carefully inspected the props. This is on a 1986 3888 with 175 Hinos and what appears to be dripless shafts - both port and starboard identical in all respects that I can see. Both engines had run well all summer. I noted that port prop had a very small ding, and was relieved because it was the kind of thing that could be more or less removed with a fingernail emery board. I knew a month ago, that side had touched some tree roots fighting the wind and going into my slip. Everything else looked square and right to me and the marina owner saw it the same way. The starboard one was a little loose so that was a minor fix to tighten. I also turned them while they were in neutral. Surprisingly the port was quite a bit more stiff than the starboard. At first I attributed this to the fact that a few weeks before I had the mechanic bring his big wrenches down to tighten a dripless shaft that was dripping. Maybe he over tightened it.

    On the other hand I have no fact base to tell me what is normal. Should these shafts be loose or should they be stiff or maybe it just does not matter. Maybe I will investigate the wrong one for the wrong reason. I could not see a previous post on this so maybe it is worth canvassing

    #2
    Check both ends of the cutlass bearing to see if it is running true, it may be mis-aligned to the cutlass, even though the shaft to engine is aligned.

    You could loosen the coupling to the engine and see if it turns freely, to re-align you need to be in the water for 24 hours.
    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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      #3
      When I haul my boat I also remove my shafts and clean the interior of the cutlass bearing. They start our w/ gritty internal growth and finsih up nice and smooth. The shafts rotate freely aferwards.

      Comment


        #4
        If the dripless seal is too tight it will be very very warm or hot when you touch it. If not, then it's not the problem. There are different stresses on the hull of the boat while sitting on blocks vs floating in the water. My boat always sits on blocks at my marina and one of the things I routinely do is turn the props by hand. I can easily turn both with two fingers, but they do not spin "freely" as there is always some slight friction. If yours turn hard with one hand or you need two hands to turn them, then you likely have a problem that needs addressing.
        Two C's 1990 3888 MY, 175 Hinos, Hurth 630 Trannys
        Past Commodore Emerald Rose Yacht Club
        Member International Order of the Blue Gavel
        MMSI: 338030604

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          #5
          Here's a link to PSS shaft seals, the predominate supplier of dripless shaft seals for the last 30 years or so:

          http://www.shaftseal.com/en/categories

          You can review the proper installation procedure and determine if your mechanic did the right thing.

          Comment


            #6
            Alignment, Alignment, if the shaft seal was that tight, it would be dead. Read my first post, I have aligned a lot of engines/ shafts, when they turn hard in dry dock it is usually the alignment through the cutlass.

            There can be alignment issues, as well as a bent strut, someone that knows what they are doing needs to check it, otherwise it is all speculation on our part.

            Check alignment out of the water, then check in the water after 24 hours.
            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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              #7
              thanks all of you - I will focus on the stiff one

              Comment


                #8
                bobsyiruncle wrote:
                thanks all of you - I will focus on the stiff one
                Spray some water into the cutlass bearing, then turn it, first!
                Pat says: DO-IT-RIGHT THE FIRST TIME!

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

                Comment


                  #9
                  There seems to be some confusion of terms between stuffing boxes and dripless shaft seals. Stuffing boxes will be hot if adjusted too tight, and that will definitely bind the shaft. Dripless seals can't really be adjusted "too tight" unless the person doing it severely over-compresses the bellows.

                  And there's no need to clean a cutlass bearing. If you have the time to pull the prop and shaft, change the cutlass. They're cheap compared to the labour involved.

                  If the shaft is hard to rotate, it's worth trying to wet the cutlass and try again. If it's still tight, check the alignment carefully.

                  Comment


                    #10
                    am considering all advice - my thinking is cutlass bearing or over tightening but won't know til I return in the spring (1200 miles away) and prior to this thread did not know enough to even pursue the investigation - It has to be loose so now I know what I did not know when I started (thanks to BOC) is that it should be loose. BTW sale on locally on infrared temperature gauges - won't miss this one given what I now know

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                      #11
                      whiskywizard wrote:
                      And there's no need to clean a cutlass bearing. If you have the time to pull the prop and shaft, change the cutlass. They're cheap compared to the labour involved.

                      If it's still tight, check the alignment carefully.
                      One my boat I maintain the alignment spot on, so my cutlass bearings have never worn out. I've replaced them but they were fine.

                      As stated, I've found minute growth in the cutlass bearings that added friction, so it was easy enough to clean out. I yank my shafts at each haul to clean and inspect the running gear. It is easy enough.

                      The issue I've discovered is that there is not one single on-line resource that defines a proper procedure for aligning a vee drive. There are plenty for straight shaft. I like the Caterpillar version. People seem to use the straight shaft procedure for vee drive, but there is no reason why it would have to work.

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                        #12
                        bearings - anything out of my reach that I cannot beat with a baseball bat probably needs to get turfed and replaced even on circumstantial evidence. I am cheap but not crazy

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                          #13
                          wingless wrote:
                          One my boat I maintain the alignment spot on, so my cutlass bearings have never worn out. I've replaced them but they were fine.

                          As stated, I've found minute growth in the cutlass bearings that added friction, so it was easy enough to clean out. I yank my shafts at each haul to clean and inspect the running gear. It is easy enough.

                          The issue I've discovered is that there is not one single on-line resource that defines a proper procedure for aligning a vee drive. There are plenty for straight shaft. I like the Caterpillar version. People seem to use the straight shaft procedure for vee drive, but there is no reason why it would have to work.
                          I have aligned a few V drives, I would not wish it on anyone, not the same as straight, not in reverse on the mounts, it is trial and error. Just a comment, CUTLASS BEARINGS DO WEAR OUT!!!!
                          Pat says: DO-IT-RIGHT THE FIRST TIME!

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

                          Comment


                            #14
                            boatworkfl wrote:
                            Just a comment, CUTLASS BEARINGS DO WEAR OUT!!!!
                            Yes - good point and worth you correcting it. Even a perfect alignment doesn't eliminate cutlass bearing wear.

                            Comment


                              #15
                              boatworkfl wrote:
                              I have aligned a few V drives, I would not wish it on anyone, not the same as straight, not in reverse on the mounts, it is trial and error.
                              No it is not trial and error. There is a methodical procedure that accounts for the geometry of a vee drive with very specific adjustments based upon the measurements.

                              Yes, it is trial and error when using ALL the on-line procedures I've found.

                              boatworkfl wrote:
                              CUTLASS BEARINGS DO WEAR OUT!
                              Yes they do. They wear out very quickly when the engine is not properly aligned. They wear out more slowly when the engine is properly aligned.

                              When I replaced mine, with hundreds of hours and many years (not a marina queen), all with spot-on alignment, they looked very good, with uniform wear, no performance issues and could have continued in-service.

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