Spark Plug for 1932 Johnson K-50

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  • April 20, 2018 at 1:53 am #9698
    Buccaneer
    Participant

      US Member

      The 3rd Edition Johnson Service Manual says the subject motor
      takes 18 mm Champion R-7 spark plugs.
      I see lots of references on the Net for #7 Champion plugs,
      but not for R-7.
      Is there a difference?

      The engine had some old Auto Lite "Transport" BT-4 plugs in it.
      I do find cross references for these, but I have idea if they’re
      correct.

      Prepare to be boarded!

      April 20, 2018 at 2:53 am #74359
      need2fish
      Participant

        http://www.gsparkplug.com/1x-champion-spark-plug-r7.html

        April 20, 2018 at 6:02 am #74362
        garry-in-michigan
        Participant

          Lifetime Member

          The 7 has a side electrode that goes over the end of the electrode, the R7 has a pin coming in from the side, used more in racing outboards. . . 😉

          April 20, 2018 at 12:23 pm #74366
          Buccaneer
          Participant

            US Member

            Thanks for the chart Garry. My 8 hp Johnson doesn’t look
            like it’s going to win any races, but maybe that was a
            selling point back in 1932….. "It has racing spark plugs"!

            I have a 6 pack of Champion D14 / 514 coming for another
            project. Will have to see how they compare to the R7 specs.

            Need2Fish……… Those plugs from Merry Old England are
            "Out of Stock", but it was nice to see the photo!

            Prepare to be boarded!

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