1940 Johnson HA-15 W/Video

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  • September 19, 2015 at 9:23 pm #2582
    marvk
    Participant

      Had a little time today to pull apart the water pump on my HA-15 2.5hp. I’ve had it out a couple of times early this Summer, but only to have it overheat. I thought I would check out the lower end pump, before I pulled the head to see if there was a blockage in the top end.

      I did find that the lower check ball was somewhat stuck. Popped it out and polished the seat and the ball itself. Thought I would give it a run to see if that was the problem. I ran it for an hour or so, and it always was warm to the touch. If I ran it high RPMs, it was hot, but cooled down when I lowered the RPMs. Overall, it ran pretty good, but not great. I need to check the compression again to see what it actually is now. I seem to remember that it was in the low to mid 60’s when I first checked it.

      Anyway, here’s the link from today; http://youtu.be/6Am6EVd4Pr8

      September 19, 2015 at 10:24 pm #24219
      willyboy
      Participant

        Very nice! Seems like it runs pretty good to me. I’m just finishing one of those up and hope mine runs as well as yours.

        September 26, 2015 at 5:26 pm #24644
        marvk
        Participant

          I checked the compression today, and I I have 70-72psi on both cylinders. I think it should be idling better.

          To anyone who has one one of these, or similar, are the main and idle jets this sensitive? Especially the idle screw. It seems every time I advance the throttle, I have to re adjust the idle screw. Manual says to adjust the idle with the main closed, and it should then be set for low through high RPMs.

          Also, on the cooling, there are the spray holes, that spray forward against the transom. That seems to be working fine, and I don’t seem to be overheating anymore. But there is also a relief hole on the port side, 90deg off of the spray holes. Is this an exhaust relief hole, or is there supposed to be cooling water exiting this hole as well?

          Thanks,

          September 27, 2015 at 5:44 pm #24706
          willyboy
          Participant

            I have the same issues with my HA-15 MarvK, every time I advanced the throttle I had to adjust the idle screw or she would die out in 30-60 seconds. I seem to have found a happy place for my main jet setting at .545 inch from the top of the carb to the base of the main jet knob. I luckily measured that distance for some reason before I disassembled my carb for cleaning and it must have been the magic spot. I managed to get it running and keep it running in the test barrel until I decided to shut it down due to getting a little too warm,i think it cools its best when their pushing a boat. Havent been able to get back to it since as I had my gallbladder out the day after I got her running after a month and a half rebuild. I’ll have to wait on taking it for a boat ride and fine tuning it until next season unless the cold weather holds off and I heal a little quicker.

            September 27, 2015 at 9:00 pm #24719
            gjonz
            Participant

              My experience is any of the little 2.5hp from the early 1940’s to the last ones made with a wobbler pump (instead of a plunger like yours) tend to run hotter than I’m used to…but the run fine.

              You may want to check the water tubes and make sure they are tight and clear of debris so water can flow as free as possible. Just because it’s spraying doesn’t always mean the water is circulating fast enough or in large enough quanity.

              But in all likelihood it is running as intended. Albeit…HOT.

              There were issues with those motors suffering vapor lock in the fuel system owing to the carb being on the same casting as the exhaust. Mine also needed the magnets charged in the flywheel.

              Good luck!

              Greg

              September 27, 2015 at 10:21 pm #24721
              cark-k
              Participant

                Very cool!

                September 27, 2015 at 10:43 pm #24722
                brian-grigsby
                Participant

                  Sounds like it’s running good. Mine was finicky as well. Great job.

                  September 28, 2015 at 3:48 am #24745
                  marvk
                  Participant

                    Thanks guys, I guess it seems to run somewhat normal. I can run it for 15-30 min at mid RPMs and it runs well. I can even hold my fingers on the cylinder side opposite the exhaust manifold. I did at one point have the vapor lock that Greg is talking about, when I first started working on this early this spring. I was getting frustrated with it, and left it sit for a few months before I started working on it again. Now I wish I started earlier. 😳

                    I think I have the cooling problem fixed, but yes, I should check the water tubes.

                    I still don’t know what the side hole is on the port side is for? I should’ve taken a picture of it before I left the lake. I’ll get one next week if I need to.

                    Thanks guys, 😉

                    September 28, 2015 at 6:50 am #24751
                    reivertom
                    Participant

                      US Member

                      My buddy had one that ran very well and would idle down to nothing IIRC. I don’t recall any issues with having to adjust for different speed settings. I like these motors and would snatch one up if I found one close to me for sale.

                      October 4, 2015 at 4:55 pm #25117
                      marvk
                      Participant

                        Was able to get a couple of pics of the openings in question today. The 2 holes on top of each other are the cooling spray holes. The other one, with what looks like a nut with a hole in it, and the oil running out of it, I assume is an exhaust relief hole?

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