1948 Sportwin Woes

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  • June 1, 2015 at 12:52 am #1650
    marvk
    Participant

      I offered to look at a ’48 3.3hp Sportwin for a co worker of mine. He gave it to me early last Fall. He started to work on it himself, and realized he was in over his head. I got it with the carb and all it’s parts in a bucket. It didn’t have a spark in either plug, so I took the ignition apart, cleaned, dressed, set the points, and got a spark on both. I got it all back together, but by the time I was ready to try it out, old man Winter came along.

      Today I tried it for the first time. It did finally start, but it runs pretty poorly. Adjusting the low speed didn’t seem to do anything. I’m assuming it’s a carb issue of some sort, but I’m hoping someone can suggest where to start on this old girl. Cooling seems to be working fine. I ran it for about 10 minutes and the spray was barely warm.

      I made a small video. It can show you, better than I can tell you.

      http://youtu.be/DdamLTp1UmM

      June 1, 2015 at 1:05 am #17319
      Buccaneer
      Participant

        US Member

        I wish mine ran that good, lol. I rather dislike that carb with the air shutter.
        If I get it started sometimes it would run at fast speed, but would usually
        die out trying to transition to a slower speed…. or visa versa. I still wonder
        if I got the pistons in backwards!!! After messing up my shoulder from pulling
        on it, it’s back on the "back of the rack"! Hope you have better luck.

        Prepare to be boarded!

        June 1, 2015 at 2:18 am #17324
        jasonh
        Participant

          I don’t think shutter linkage is working or hooked up. It sounds like spark is advancing but carb and air intake isn’t opening up.

          June 1, 2015 at 2:34 am #17327
          jasonh
          Participant

            Perhaps the throttle spring, #29, is not hooked up?

            June 1, 2015 at 3:05 pm #17352
            marvk
            Participant

              I think you are on to something Jason. When I assembled it back together last Fall, I remember not being sure where the other end of the spring attached to. I’m gathering info this week so I have a better idea of what to look for. I left it up at the lake, so I won’t be able to look at it ’till this weekend.

              Thanks,

              June 3, 2015 at 12:10 pm #17492
              marvk
              Participant

                Can anyone enlighten me on how this actually is supposed to work? I’m not familiar with this type of carb.

                Thanks

                June 3, 2015 at 1:38 pm #17497
                Buccaneer
                Participant

                  US Member

                  Marv, read this thread for a little more info on those carbs……

                  viewtopic.php?f=2&t=705

                  Prepare to be boarded!

                  June 3, 2015 at 3:12 pm #17502
                  marvk
                  Participant

                    Thanks Bucc, I’ll give it a read. I think it’s something in the throttle linkage, and/or the air shutter isn’t set right, or maybe a part is missing, or just not hooked up correctly.

                    June 3, 2015 at 5:02 pm #17509
                    jasonh
                    Participant

                      The other thing worth noting is the cam follower rides inside mag cam which is opposite most motors. Although I do not suspect this is issue with yours. I am sticking with spring or rod not being hooked up.

                      June 6, 2015 at 2:28 am #17677
                      marvk
                      Participant

                        I had a chance to look at it more closely tonight. Jason, you were kinda right. Although I had everything hooked up correctly, the extension throttle spring, (#29) has been stretched and doesn’t overcome the friction of the throttle shutter, so it was effectively like it wasn’t hooked up at all. I’ll either have to try and find another one, or cut this one shorter and reshape the hook.

                        If I understand how it works, the spring tension keeps the cam roller tight up against the follower, and moves the throttle shutter (#32). The rod links up to the cam lever (#43), and that’s connected the the air shutter (#60). 😕

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