1940 Johnson KA-10 9.8 hp

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  • July 25, 2015 at 11:07 pm #2112
    Buccaneer
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      US Member - 1 Year (includes $3 online payment fee)

      I picked up a 1940 Johnson KA-10, 9.8 hp today.
      Is there any parts diagrams floating around for these
      models?
      I seen two other Johnsons, one also a KA-10, and
      the other looks almost identical except it has a rewind
      on it. What model might have that been?
      Thanks, Buccaneer

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      July 26, 2015 at 5:25 am #20891
      Mumbles
      Participant

        The K motor with the rewind would probably be a KD 15. I’ll have to look but I’m sure I have diagrams for the earlier KA 37, 38 and maybe a KA 39. These motors are all similar with minor differences but the one thing they do share is the 8:1 fuel ratio.

        July 26, 2015 at 1:38 pm #20902
        Buccaneer
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          US Member - 1 Year (includes $3 online payment fee)

          Wow……. no wonder it’s not froze up……. probably an inch
          of oil residue inside the crank case!
          The guy wanted $150 each for the KA-10 and the other one with a
          rewind. I was out of trunk space and money by that time, but
          felt okay as I got my KA-10 with an antique foldable stand
          for $100. The only thing that appears missing is the little
          cover that goes over the spark plugs in back.
          With the cylinder configuration it has, with one piston
          over the top of the other on the back side, would it be
          alternate firing with two coils?
          Thanks.

          Prepare to be boarded!

          July 26, 2015 at 3:11 pm #20907
          Mumbles
          Participant

            Yes, they are smooth running alternate firing motors. They have a very large rotary valve with two sealing rings on the crank and I think this is why they need the oil rich mixture. There’s no water pumps on the KA 37 – 39 so a hose has to be hooked up to a fitting on the bottom of the cylinder to run them on a stand. Here’s a mag.

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