1949 Mercury KF3 Comet

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  • March 4, 2026 at 11:27 am #305687
    Aidan Smith
    Participant

      US Junior Member

      Working on fully restoring a KF3, as I have been made aware they aren’t the most common thing.

      Mine is looking worse for wear. It has a Scintilla mag, and it runs decently at mid speed, but struggles and stalls when I try to open it up.

      Carb is decently clean as well. I have spare Scintilla parts as well if need be. Has anyone worked on one before?

      I am guessing it shares an impeller with the Mark 6, as the lower midsection and unit look similar. Mine pumps plenty of water, so not too worried at the current moment.

      Tank has a softball-sized dent in the side, so I am looking for an ideally dent free tank.

       

      Any help with this would be great, thanks!

      "Shells sink, dreams float. Life's good on our boat."
      1949 Mercury KE-4
      1952 Mercury KF-3,-5,-7
      1952 Mercury KG-7Q

      1937 Evinrude Scout
      1938 Elto Pal
      1946 Evinrude Ranger

      March 4, 2026 at 9:22 pm #305958
      Waunnaboat
      Participant

        US Junior Member

        Maybe you are having throttle linkage issues if it is stalling like that?  Have you run it for longer periods?  if the coil or condenser are bad they will sputter up and stall when you throttle them up or they will run for around a minute when at slower speeds.  Try checking out the throttle linkage and then replace the condensers as a good measure even if you figure it out with the throttle.  I had a ke7 with Bendix and it did exactly what you described, and I suspect the condensers or coils were the issue but I had difficulty removing the flywheel and offloaded the motor instead of fixing it because I’m into the older stuff anyway.

        "Outboards seem to multiply exponentially..........I find that for every finished project, there are two more waiting to be completed."

        March 4, 2026 at 10:16 pm #305980
        Aidan Smith
        Participant

          US Junior Member

          Waunnaboat,

          I figured out my issue. There was a small grit that was stopping up the carb from fuel flow, and also the points reset themselves to fully closed when I tightened the screws, and didn’t notice!

           

          Thanks!

          "Shells sink, dreams float. Life's good on our boat."
          1949 Mercury KE-4
          1952 Mercury KF-3,-5,-7
          1952 Mercury KG-7Q

          1937 Evinrude Scout
          1938 Elto Pal
          1946 Evinrude Ranger

          March 5, 2026 at 7:30 am #306055
          fastjohn
          Participant

            US MEMBER PAY BY CHECK

            Impeller is the same as a KF-5, not a Mark 5 or 6.

            1 user thanked author for this post.
            Aidan Smith
            March 7, 2026 at 10:24 am #306915
            Aidan Smith
            Participant

              US Junior Member

              Perfect… I think I have some extras, but for now it seems to be pumping plenty of water. Thank you!

              "Shells sink, dreams float. Life's good on our boat."
              1949 Mercury KE-4
              1952 Mercury KF-3,-5,-7
              1952 Mercury KG-7Q

              1937 Evinrude Scout
              1938 Elto Pal
              1946 Evinrude Ranger

              March 7, 2026 at 12:30 pm #306978
              green-thumbs
              Participant

                US MEMBER PAY BY CHECK

                Mercury made several runs of KF3, Each different in some way, Final version had Repco/Phelon magneto,

                Louis

                March 7, 2026 at 1:08 pm #306992
                Aidan Smith
                Participant

                  US Junior Member

                  I have # 359922, which is a KF-3(1). It has the Scintilla mag, but works great.

                  I read the paper wrong, it is a 1949 instead of a 1950.

                   

                  "Shells sink, dreams float. Life's good on our boat."
                  1949 Mercury KE-4
                  1952 Mercury KF-3,-5,-7
                  1952 Mercury KG-7Q

                  1937 Evinrude Scout
                  1938 Elto Pal
                  1946 Evinrude Ranger

                  March 7, 2026 at 9:56 pm #307210
                  Tubs
                  Participant

                    Aidan Smith wrote:

                    Waunnaboat,

                    I figured out my issue. There was a small grit that was stopping up the carb from fuel flow, and also the points reset themselves to fully closed when I tightened the screws, and didn’t notice!

                     

                    Thanks!

                    Learning by experience. Self-taught. Someone could have told you to always re-check the gap after tightening the screw. Could have red it some where. But the lessons that you teach yourself your not likely to ever forget.    

                     

                     

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

                    2 users thanked author for this post.
                    David Bartlett, Aidan Smith
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