Trying to turn the shaft by hand

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  • benbox
    Member
    • Jan 2022
    • 4

    Trying to turn the shaft by hand

    Hello all

    I hope to gather some wisdom from the all the salty experience around here. I am having that common problem where the A4 in our 1982 Catalina 30 runs, idles, and revs smoothly like a top when neutral, but stalls within seconds when put into gear. I have read dozens and dozens of discussion threads so I have a lengthy list of troubleshooting items. However, due to my inexperience, I am running into some issues in the first step -- checking to see if my prop shaft will turn by hand in neutral.

    1) With 2 of us boat partners gripping the prop shaft, while in neutral, we were unable to budget the prop shaft at all, not even a fraction of a mil, using our bare hands. However -- we do not have a standard stuffing tube, instead we have one of those PSS Shaft Seal systems, where the stainless steel collar is pressed against a graphite puck under pressure from the rubber bellows. Should the shaft still be turning freely by hand even with the PSS shaft seal system?

    2) Would it be a worthwhile test, if I de-coupled the prop shaft from the coupling flange at the engine shaft output, and then tried again to turn the shaft by hand? (And if I understand correctly, I should carefully use my feeler gauges when slowly re-tighten the bolts connecting my prop shaft to the coupling flange - correct?)

    We're already planning to hire a diver to check for lines or other debris fouling the prop or shaft outside the boat, but I want to check for excess shaft binding this weekend. Was just hoping that #1 above -- was already good enough indicator that my shaft binding is the issue.

    BACKGROUND: New (to us) boat had an extremely well maintained A4, and motored everywhere with no problems. At end of March, we motored 2 hours to get to a shipyard where, for the next 4 weeks, we got all standing rigging replaced. Boat was never lifted out of the water. After 4 weeks, we start the engine, put into gear, and stalled after a few minutes.

    After more attempts, the engine now stalls almost immediately (prop shaft turns 4-5 times) and then it stops). With all of this, I believe the issue is shaft binding, so was hoping to confirm.

    Would appreciate if someone could confirm if in neutral, with PSS seal, prop shaft could be easily turned.

    thanks
  • msmith10
    Afourian MVP
    • Jun 2006
    • 475

    #2
    Yes, you should be able to turn the shaft by hand. I have an old fashioned stuffing box so I don't know if the PSS is adjustable like a stuffing box, but if you can't turn the shaft by hand there's a problem. Are you sure the reversing gear is in neutral? Can you feel the forward detent clicking in and out as you move the shifter?
    Mark Smith
    1977 c&c30 Mk1 hailing from Port Clinton, Ohio

    Comment

    • Dave Neptune
      Afourian MVP, Professor Emeritus
      • Jan 2007
      • 5063

      #3
      A PSS shaft should turn very easy if truly in neutral of which the direct drive trans is extremely illusive of.

      Does it move at all or just stuck? Since you were in and out of the yard hopeful the strut if so equipped did not get bumped.

      Do check and see that the prop is not fouled as it could save a lot of trouble.

      Did the shaft turn slowly when in neutral? Does your shifter linkage feel smooth?

      Dave Neptune

      Comment

      • benbox
        Member
        • Jan 2022
        • 4

        #4
        Sounds like it's fouled

        Hi all - thank you for the answers so far. In reply -- yes, I've verified that the gear is truly in neutral. Am able to feel the detente click in, and that's why the engine immediately dies.

        Interestingly, when we first tried to move the boat out of the slip, the engine died after running a couple of minutes. Subsequent attempts showed that the engine dies progressively quicker and quicker after putting boat in gear. It feels like something might have progressively wrapped itself tighter and tighter around the shaft. Now it dies immediately after shifting into gear.

        When I last attempted to, I verified as best I could that the engine is in neutral. I could not budge the shaft, even a little.

        thanks for the tips so far. We have a diver lined up so we will know soon. I'll post the results, and I'm hoping that something obvious will be found.

        Ben

        Comment

        • Dave Neptune
          Afourian MVP, Professor Emeritus
          • Jan 2007
          • 5063

          #5
          Trans basic

          First there is no real neutral or reverse in the direct drive. The "detent" only locks the trans in forward. To use reverse pressure needs to be applied to the shifter to hold in reverse as there is no means for the trans to hold itself in "reverse". Now neutral is sort of in between however t due to the friction of the mechanism the trans can and usually does spin a bit when in the neutral range of shifter position. Depending on how the trans is adjusted there can be a little or a lot of drag in the neutral range.

          How does the shift cable look and does it move smoothly? Any rust or wires poking out of the sleeve?

          When the engine is idling in neutral is the shaft turning at all?

          You could put a mask on and stick your head under water and take a look or wait for a diver.

          Dave Neptune

          Comment

          • Sam
            Afourian MVP
            • Apr 2010
            • 324

            #6
            Good advise - this sounds exactly what happens when a dock line, piece of line or even a large plastic bag wraps around the prop shaft. Had to go down with googles and a knife in across my mouth and then cut it away.

            Comment

            • edwardc
              Afourian MVP
              • Aug 2009
              • 2511

              #7
              Originally posted by Dave Neptune View Post
              ... You could put a mask on and stick your head under water ...
              Or try a GoPro on a stick.
              @(^.^)@ Ed
              1977 Pearson P-323 "Dolce Vita"
              with rebuilt Atomic-4

              sigpic

              Comment

              • benbox
                Member
                • Jan 2022
                • 4

                #8
                Interesting change in behavior

                Hello skippers

                I've finally had some hands-on time with the boat and the engine since my previous attempt at turning the prop shaft. Inexplicably the behavior has changed, so now it's a bit of a nautical mystery. Here is the latest behavior that I've found, after working the engine room for quite some time over last 2 evenings.

                1) This time, after double-checking that the transmission in truly in neutral, I reached down into the bilge to turn the shaft. Shockingly, now it turns easily just using my right hand. It's possible that my previous attempt was not truly in gear. But it seems clear that the propshaft is not bound - it can turn quite easily.

                2) I started the engine, and both during and after warmup while in neutral, I looked in the bilge and the prop shaft was in fact slowly free-spinning. So, clearly, double-confirmation that propshaft binding was not the problem.

                3) After warmup of about 20 minutes (during which I observed some interesting behavior changes from before the rigging refit - to be detailed later), I then attempted to replicate my shipmate's experiences -- to no avail. I kept the RPM idling at 1200 rpm, 1000 rpm, and 800 rpm, and shifted into gear. The engine under load bogged down a couple hundred rpms -- but did NOT stall. I repeated this at all 3 above rpms, both with the choke open and closed. Same result -- when in idle, and shifting into both forward and reverse, I **could not stall the engine** at all 3 of those RPMs.

                My shipmates / co-skippers and I are baffled. Just 2 days before, shifting into gear from neutral at idle killed the engine almost instantly, as in within seconds. We have no explanation... and a degree mistrust of the engine now; but I kept experimenting:

                Now the observed subtle differences in engine behavior from before the rigging refit:

                - Before, upon cold start, once the engine turns over and starts, I would immediately push in (open up) the choke, and as I would push it in, the engine would instantly start running faster, so that I could throttle back down to idle for the remainder of the warmup.

                - However, now, when I initially, and reach over to push in/open the choke, the engine starts to stumble and slow down. I have to close the choke again to keep it running and warming.

                - Before, when I backed off the throttle all the way back down to bottom when the engine was partially warm, it would continue to idle at around 750. Now, when i do so while partially warm, the engine dies.

                - Now, with the transmission in either forward/reverse gear, and engine fully warm, with choke pushed in (open), it can idle just fine. However, when I open up the throttle with the engine in gear and under load, the RPMS *do not advance* and engine feels unhappy. But, I then immediately pull out/close the choke, the RPMs would start to rise and suddenly I have power to the props where it can churn water.

                Now I speculate that my co-skippers probably run into something similar - I've asked them, but they don't remember specifically the choke setting when they ran into the stalling problem. I think maybe they had the engine in gear, throttled up, but choke was open (as per normal procedure), but the engine stumbled and died under load.

                Given that I'm a relative newbie at playing with carbureted engines, I'm guessing from the behavior changes, having to choke the engine under higher throttle/load, and generally the engine being happier with the choke closed -- I guess that we have an abnormally lean mixture happening. Would those of you with more experience think the same?

                I have a hypothesis as to how this came about -- when we went into the yard for the standing rigging refit, we motored across the bay and ran the gas tank quite low, below the 1/4 full mark. Perhaps if we were sucking in gas near the bottom, that some old debris must has gone past the filters and into the carburetor, and just the smallest bit of debris in one of the jets would contribute to this lean running condition.

                Hopefully watching Don's carburetor cleaning tips on Youtube and attempting the job would be a good step. Might there be other items that we can check first? (for example, we have 2 in-line fuel filters, I guess one of which is a polish filter), cleaning those out first before taking off the carb might be an easier first step. Any additional suggestions?

                I hope our saga has been entertaining

                Ben

                Comment

                • edwardc
                  Afourian MVP
                  • Aug 2009
                  • 2511

                  #9
                  It sounds like you're right on top of it. The behavior you are describing is very consistent with a fuel supply obstruction, most likely in the carb.

                  I would recommend first siphoning some gas out of the bottom of the tank and examine it for debris or water. If you've got dirty gas, you must clean up the tank; otherwise, the problem will just keep coming back no matter how many times you clean the carb.
                  @(^.^)@ Ed
                  1977 Pearson P-323 "Dolce Vita"
                  with rebuilt Atomic-4

                  sigpic

                  Comment

                  • ndutton
                    Afourian MVP
                    • May 2009
                    • 9777

                    #10
                    Originally posted by benbox View Post
                    we motored across the bay and ran the gas tank quite low, below the 1/4 full mark. Perhaps if we were sucking in gas near the bottom, that some old debris must has gone past the filters and into the carburetor, and just the smallest bit of debris in one of the jets would contribute to this lean running condition.
                    FYI, you're ALWAYS sucking gas from the bottom. The elbow on the top of the tank (where the fuel hose connects) has a tube that draws all the fuel from the bottom of the tank.
                    Neil
                    1977 Catalina 30
                    San Pedro, California
                    prior boats 1987 Westsail 32, 1970 Catalina 22
                    Had my hands in a few others

                    Comment

                    • benbox
                      Member
                      • Jan 2022
                      • 4

                      #11
                      I'm posting an update after the troubleshooting work the last couple of weeks, so that we can close out this thread. We finally proved that the problem was water in the fuel. First of all, we siphoned out all the gasoline from the tank, and we saw a significant separated amount of water at the bottom of the glass that we poured the sample gas from the tank into.

                      Second and most significantly, we ran a test where we completely bypassed the fuel system: we pulled the fuel hose from the carburetor and routed it to a spare gas can with a spare length of fuel hose, and then we hung a source of fresh clean gasoline (a small bottle) from the cabin head, and gravity-fed clean fuel to the carburetor via another length of fuel hose.

                      Using this fuel bypass contraption, I started the A4 and after some initial hesitation, the engine finally ran as it should. It throttled up quite easily without needing any choke, was able to run in high RPM under load, and the choke behavior at startup seems to be back to normal. Naturally, had the carburetor been gummed up with any debris, simply running know fresh fuel through the system should not have solved it.

                      So next step is to fill up the now-fully drained tank with fresh clean gas and hopefully have a fun un-eventful Memorial Day sail coming up.

                      One more thing:

                      A friend of ours does some side work diving and cleaning the boats at our marina. Last weekend we had completed work on a neighboring boat, and because he's nice, and because he knows about our difficulties, he swam over to our boat to take a look. And -- he cut away and removed about 2 yards of a length of dock line wrapped around our prop.

                      Amazing... it's never just the one thing.

                      Thanks everyone for their advice.
                      Ben

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