Home Forum Ask A Member 1931 Johnson OA-55 – Phase 2

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  • #294220
    Tubs
    Participant
      Pretty cold here right now but things could be warming up a bit next week. Not warm enough to put water in the barrel but maybe opening the door for some bench testing. Forecast that far out aren’t reliable. Could change to snow by then.

      A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

      #294221
      Sam M.
      Participant

        Canada Junior Member

        Tubs, it looks like you’ve made lots of progress!  I’m curious, what’s the purpose behind this motor having 2 piston rings near the top of the piston and 1 more way below?

        #294226
        Tubs
        Participant
          Cant say why they had the 3rd ring. Unless there are some documents around there is no way to know for sure . However we can speculate. My first guess would be controlling the fuel charge as the piston pass over the ports. Or possibly to improve crankcase pressure. Or maybe is to stabilize that heavy cast piston so it doesn’t rock in the cylinder. Or to keep oil between the upper and lower rings for better lubrication. This is early in engine design. Things were being tried only to be dropped as they didn’t really work as intended, cost didn’t justify the benefit, but most likely, same as today, engineers have to keep coming up with something different, no matter how well something works, if they want to have a job.

               

           

          A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

          2 users thanked author for this post.
          #294230
          T….in Wisconsin
          Participant

            US Member

            .

            #294239
            Tubs
            Participant
              I posted the first power head pictures before I had removed this other cylinder. When I pulled it back there was a piece of the back fire suppressor sticking out. There was just enough of it remaining to keep it from going into the crankcase. This, and water pump key, would seem to indicate this motor had a death wish. Rings, same as the other side. Freed up pretty easily except for the top ring. Stuck in the area of the exhaust port. I broke it however. Except for having around .005 to .006 of taper, the cylinders look to be in good condition. With all this carbon I’m surprised there is 0 scoring of the pistons or cylinders.

                   

              6A

              A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

              #294253
              Bob Wight
              Participant

                US Member

                Good thing you decided to open up the crankcase – not much more run time and that back fire gizmo would have been down into the guts of the case.   I wonder how many motors got destroyed by those suppressors.

                Bob

                1937 Champion D2C Deluxe Lite Twin
                1954 Johnson CD-11
                1955 Johnson QD-16
                1957 Evinrude Fastwin 18
                1958 Johnson QD-19
                1958 Johnson FD-12
                1959 Johnson QD-20

                “Every 20 minute job is only a broken bolt away from a 3-day project.”
                "Every time you remove a broken or seized bolt an angel gets his wings."

                #294272
                Tubs
                Participant
                  I think this is my 5th or 6th Johnson with this power head. Didn’t have a reason the remove the cylinders in any of them. They have moved on so I can’t check if the back fire suppressor is still in any of them. I think if I get anymore of these I’ll slide at least one cylinder back far enough to check if they are still in there.

                       

                  A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

                  #294351
                  Tubs
                  Participant

                    I went back and forth on weather to remove one of the end caps of the tank and decided not to. Working on the tank I got to the point where it wasn’t worth the time to remove what dents remained. This tank doesn’t need to be polished. Just needs a little filler. Wanted to see what I could do for the end caps. I aired up the tank and using a heat gun and my hammer, I began working on one end. Turns out that the only thing holding the end cap on was a little solder, just on the edge of the end cap. Apparently I got the cap hot enough that the solder let go. The end cap flew off, ending up on the floor, folded up like a taco. Don’t have a picture as I was somewhat concerned weather I would be able straighten it back out. The Boathouse repair took about an hour and a half. It’s close enough no one will noticed. Being that I now had one end open I began looking for something to use to straighten the cap on other end. The 2″ PVC pipe with a union and end cap, over a towel, worked well. The union and end cap were left over from a rear pinion seal install on my truck not too long ago. Now, having access to the inside of the tank, I wanted to work on the remaining dents a bit more before soldering the cap back on. There is a link to a video link for those who may be interested.
                    https://youtu.be/wEB_ZG23usA

                     

                    7A
                    7B

                     

                    A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

                    #294357
                    bob-d
                    Participant

                      US Member

                      Yep this tank repair is just Tubs showing off again😂.
                      Seriously Tubs, the tank came out spectacular…and that’s without the paint and decal. You gave us all a masterclass on tank repair. Thanks for the great write up and video. Interesting find with the fire suppressors. I have never seen any in that bad of shape.
                      I have  Callie 5 speed that backfired constantly. It turned out to be the mixture screw letting in too much air . Very spectacular I might add!
                      I suppose this motor might have been banging for a while to break them up? I’m sure you will figure it out once you get it into the barrel.
                      PS Don’t forget to throw the Cub in the barrel too. Can’t wait to see that run as well.

                      Bob D

                      #294359
                      Bob Wight
                      Participant

                        US Member

                        Another great piece of work, Tubs.   Well done.

                        Bob

                        1937 Champion D2C Deluxe Lite Twin
                        1954 Johnson CD-11
                        1955 Johnson QD-16
                        1957 Evinrude Fastwin 18
                        1958 Johnson QD-19
                        1958 Johnson FD-12
                        1959 Johnson QD-20

                        “Every 20 minute job is only a broken bolt away from a 3-day project.”
                        "Every time you remove a broken or seized bolt an angel gets his wings."

                      Viewing 10 posts - 11 through 20 (of 27 total)
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