1948 Johnson Seahorse HD25 Gasket

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  • May 12, 2015 at 12:57 am #1466
    Anonymous

      I probably shouldn’t of done this but its too late now. I removed the carburetor to work on it and the gasket (pn 43-221 muffler to cylinder gasket) just disintegrated. So I need some advice from the experts. Is there anyone making these gaskets that I can buy or how can I make one myself. Any advice to solve this problem would be appreciated. Thanks in advance.

      May 12, 2015 at 2:37 am #15761
      garry-in-michigan
      Participant

        Lifetime Member

        Doug Penn may have that gasket. If not, how good are you with an Xacto knife? Most auto parts stores carry gasket material by the sheet or roll. It is just a mater of tracing the part on the material and then cutting around the lines.

        May 12, 2015 at 6:45 am #15770
        legendre
        Participant

          Hey Willy,

          Very easy to make this gasket. get some 1/32" rubber-fiber gasket material, as is sold at O’Reilly Auto. Trace out, or tap out the new gasket using the carb mounting flange as a guide. I’ve made several of them this way, it only takes about ten minutes tops to finish one off.

          May 12, 2015 at 7:03 am #15772
          thepetrolist
          Participant
            quote legendre:

            Hey Willy,

            Very easy to make this gasket. get some 1/32″ rubber-fiber gasket material, as is sold at O’Reilly Auto. Trace out, or tap out the new gasket using the carb mounting flange as a guide. I’ve made several of them this way, it only takes about ten minutes tops to finish one off.

            + 1

            I recently made one for my 1951 HD-26. It only takes about ten minutes as Legendre said, and it does work like a charm. I know that making gaskets seems hard before you try, believe me, when I was younger I did everything to not have to make my own gaskets simply because I thought it was hard.. 😆
            And it is much simpler (and quicker!) to make your own gaskets than trying to find them for sale, especially if you got a somewhat unusual engne

            May 13, 2015 at 11:16 pm #15884
            Anonymous

              Thanks for the info everyone. Doug Penn is actually sending me the gasket. If its not the right one, I will make one as all of you suggested. Thanks for your help everyone.

              May 13, 2015 at 11:53 pm #15888
              aquasonic
              Participant

                US Member

                I have made these gaskets before, and they are a complex gasket. Beyond an Xacto knife you really need a punch set. I find it hard to believe that someone can actually make a properly fitting one in ten minutes. I’d like to see that!

                Instead of making gaskets, I would much rather contact one of my vintage parts vendors from this club and buy a perfectly fitting NOS gasket at a very reasonable price. I’m talking $3.00 to $4.00 here, plus about $1.00 shipping.

                Willy, you made a good decision to go through Doug Penn.

                May 14, 2015 at 12:28 am #15891
                legendre
                Participant

                  We must be talking about different gaskets, as the one for the TD20 carb flange (same as HD25?) is roughly shaped like an isosceles triangle and has exactly three round holes. Has two 1/4" holes and one about 3/4" or so.

                  Measures about 2.5" across the base, and 1.25" or so in height.

                  May 14, 2015 at 12:52 am #15894
                  aquasonic
                  Participant

                    US Member

                    OK, now I know why we have a difference of opinion here… The TD-20 has a separate carburetor gasket with the two studs that mount to the intake/exhaust manifold. The TD-20 gasket is a simple carb intake with two holes for the mounting studs. In shape it looks similar to 1950’s and later carburetor gaskets.

                    The HD-25, on the other hand, has a carburetor that is integral to the intake and exhaust manifold. Everything is in one piece, so the only gasket is the much more complex intake/exhaust manifold gasket with all of those radius’ and ports. Check out the gasket 43-221 that Willy referred to, and you will see.

                    https://www.dropbox.com/sh/4ufxp2fhcurs … on%20Parts

                    May 14, 2015 at 1:55 am #15901
                    legendre
                    Participant

                      Ok I see the issue. The gasket being discussed is more akin to #41-337 – the one that seals the TD20 manifold to the block. And yes, it’s quite a bit more complicated than the small carb gasket I was thinking about.

                      I’ve made a couple of those larger ones as well, and the time was more like 45 minutes using a combination of a scissors and the tapping method.

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