1957 Johnson 10 Help

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  • September 30, 2018 at 12:42 pm #11394
    scubachuck
    Participant

      US Member - 2 Years

      I have a 1957 Johnson 10 that runs great and idles great but some days will run for 5 seconds and dies starts up then dies so on and so on again does matter if i pull choke out still dies. Glass bowel is always full and no water in the gas

      have replaced coils points condensers wires and plugs

      have rebuilt carb and also replaced carb from another motor

      September 30, 2018 at 2:39 pm #83740
      frankr
      Participant

        US Member

        As a temporary test, remove the filter from the glass bowl. If it runs now, the filter is partially clogged and restricting the fuel flow into the carb. BTW, "full" is not the normal condition for the glass bowl. Almost empty is normal. Capillary action or something like that.

        September 30, 2018 at 2:43 pm #83741
        scubachuck
        Participant

          US Member - 2 Years

          Thanks will try when I get home
          when I took the other carb off another running motor it did the same thing but will try

          September 30, 2018 at 2:48 pm #83742
          scubachuck
          Participant

            US Member - 2 Years

            was thinking about trying a different flywheel because whatever the problem it affects both cylinders

            September 30, 2018 at 3:01 pm #83744
            outbdnut2
            Participant

              US Member

              You may have a small piece of foreign material you can hardly see sometimes blocking the hi speed jet in the bottom of the float bowl or it could be below the float needle seat – that seat has a very small opening and it doesn’t take much upstream of it to block it. It could be a fragment of an old rubber gasline hose.
              Dave

              September 30, 2018 at 3:19 pm #83745
              Steve D
              Participant

                Tank holding pressure? Cap on tight?

                September 30, 2018 at 5:02 pm #83751
                Mumbles
                Participant

                  If the motor has the original fuel and air lines going to the connector, the lines will get brittle and crack over time causing a leak in the air line. If the airline is leaking, it can’t pressurise the tank and the motor will starve for fuel. Also, if the tank is almost empty, it can take a little while for the air pressure to build up and pumping the thumb button on the tank a few times will be necessary to keep the motor running until there is enough air pressure to deliver the fuel to the carb. After running the motor for a short while, you should hear the sound of pressurised air escaping when you crack open the tanks filler cap.

                  October 1, 2018 at 11:36 pm #83845
                  fleetwin
                  Participant

                    US Member - 2 Years

                    Like Mumbles says, if the pressure tank/system/line is not working properly, it will create a crankcase leak/lean condition like you describe….Perhaps the fuel connector orings are messed up letting air leak out of line that is supposed to pressurize the tank…I would think you would be able to see/hear air escaping through the connector, but who knows…

                    October 2, 2018 at 4:12 pm #83879
                    scubachuck
                    Participant

                      US Member - 2 Years

                      thanks all for the help The problem was the gasket for the fuel cap sometimes it would seal and other times leak air
                      Again thank you all

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