Sparkplug Neptune 15B2

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  • July 25, 2024 at 6:29 pm #289434
    Ronald Smith
    Participant

      What plug does a Neptune 15B2 use?

      July 26, 2024 at 9:51 pm #289453
      joecb
      Participant

        US Member

        Doing a little research in the “Old outboard Book” looks like your motor is a 2 Hp Muncie/ Neptune that uses a Champion 6M  Gap .025

        superseded by a Champion K15J. That may still be an old number, but see where it leads you

        Joe B

        PS, really not critical , my $0.02 worth

        August 1, 2024 at 2:15 pm #289579
        Ronald Smith
        Participant

          Thanks. I cross referenced the K-15J to an Autolight. Got a Neptune 15B2 in a package deal for 3 motors. $40 each. Also an Evinrude 4407 Ranger and a Johnson TN27. All have spark and compression. So, I put a carb I kit in it. The cork was dry and pristine. So I gave to several coats of hot fuel dope. Cleaned the tank. Still trying to find a good way to do that. First acetone. Came out only slightly yellow with varnish. Then denatured alcohol with nuts. That really got a lot out. Then Rust-Oleum rust remover. Dilute phosphoric acid. My next tank will try muriatic acid. Now with your help and a plug, test fire. Will pull mag rotor and clean points if needed. Pictures later. Also ordered the Old Outboard. Thanks again.

          August 2, 2024 at 7:16 pm #289590
          joecb
          Participant

            US Member

            While we are on the subject of spark plugs… you may or may not know that the “J” sufix on obsolete Champion plugs indicated a plug that has a shortened ground electrode, where the ground electrode only extends to the center of the positive electrode. These plugs were intended to minimize carbon deposit shorting across the gap. You can convert any Champion plug to a “J” by filing back the ground electrode. I have heard that the “J” had its origin as in,  Johnson Outboard Motors… perhaps.

            Joe B

            August 3, 2024 at 8:16 am #289593
            stanley
            Participant

              US Member - 2 Years

              Well,Champion was making a”J63” plug in 1920,before Johnson started outboard production.It was a 18mm plug,semi aircraft style and was early motorcycle plug.The AC regular metric version was the Johnson factory installed plug in the early A models.

              August 3, 2024 at 10:35 am #289595
              joecb
              Participant

                US Member

                The “J” I was referring to is the sufix “J”… comes AFTER the plug number, as in K 15 J

                Joe B

                August 3, 2024 at 11:59 am #289596
                stanley
                Participant

                  US Member - 2 Years

                  Joe,I apologize,I read right past the “suffix” in your comment.It is interesting that early on AC was Johnson factory plug and then about 1930 Champion took over.I wonder what the reason was for the switch.

                  August 3, 2024 at 2:30 pm #289598
                  joecb
                  Participant

                    US Member

                    I had heard that by the early thirties AC then a division of General Motors had all their production capacity dedicated to GM vehicle production. They weren’t messing around with other lines.  If true , makes sense.

                    Joe B

                    August 3, 2024 at 4:40 pm #289603
                    stanley
                    Participant

                      US Member - 2 Years

                      That does make does make sense.A great book that covers a lot of those early days of the auto industry is “Fast Times of Albert Champion”,founder of both Champion and AC.

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