History of the FD Johnson series

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  • September 18, 2015 at 10:50 pm #2576
    wiscoboater
    Participant

      Hi guys,
      My collection of the FD’s just keeps growing. I have a 59, 63, 67, and just picked up a 76 ( I know, the 76 is not technically a FD but basically the same powerhead ). I’m trying to educate myself here on the motors and have a few questions. My 59 is an 18hp. In 66 I believe they were upgraded to 20hp. Later, in 69 or 70 they became 25hp. Not much really changed on the power head through those years. I have been told the big jump from 20 to 25 was due to some enhanced exhaust tuning in the leg and possibly some re jetting in the carb. What gave them the 2hp increase in 66?
      Was it carb, or exhaust? Or was it a change from how they were rated, Flywheel VS prop HP numbers? I’m trying to put together the fastest FD package I can using the motors at my disposal. Anyone have any info or thoughts?

      September 18, 2015 at 11:20 pm #24166
      frankr
      Participant

        US Member

        Don’t believe everything you hear. Even me. But if you will listen, the 18 and 20 were the same engine, but with a bit higher compression in the 20. As for the carburetor, I think they were the same, but can’t swear to it without measuring the venturiis. That stuff about rejetting is BS. 18 and 20 were made in the same years, so it isn’t the way they measured it either. As for the 25, there were a number of changes. Different pistons, different cylinder head, different exhaust tuning, different carburetor, etc. Don’t you dare to think you can make a 25 from an 18 by swapping any one thing. You will probably make it worse. If you want the fastest FD (22 cubic inch), get at 25 to begin with. Better yet move up to a later model with thru-the-prop exhaust. Or just get a 35 and be happy.

        September 18, 2015 at 11:28 pm #24167
        chris-p
        Participant

          They did not start measuring hp at the prop until the roughly the mid 80s. Much after the motors you have listed there were produced.

          I have played with swapping parts for Saturday rainy afternoon fun. As Frank stated, things only go downhill. If you want a 25, get a 25.

          September 18, 2015 at 11:37 pm #24168
          wiscoboater
          Participant

            That’s the thing, I don’t want a 25. I want to either use the 63 or the 67, but I love the looks of the 59! To many motors, to many decisions… NOT ENOUGH BOATS!!

            September 19, 2015 at 1:09 pm #24203
            fleetwin
            Participant

              US Member - 2 Years

              OK, you like your 59 FD, I agree! Loved the graphics/and cover on those engines! I did NOT like that cheesy plastic applique used on the 1960 models!
              Don’t screw around with your 59, leave it as is. Get a tiny tach, and try different props/motor heights/transom angles.

              September 19, 2015 at 4:15 pm #24211
              reivertom
              Participant

                US Member

                Playing with props/pitches may bridge the difference between your 18 and 20 to the point it won’t be that noticeable.

                September 19, 2015 at 10:40 pm #24222
                wiscoboater
                Participant

                  I have a killer bronze 8 1/2 X 11 2 blade that fits the 59… so I guess this will be the set up. Nobody hate me, But I’m going to throw the Estart from the 63 on it. J/E’s are the best!

                  September 21, 2015 at 7:13 am #24302
                  enrico-italy
                  Participant

                    I’m wondering why the 1976 fd isn’t "tecnically" a FD.
                    The difference between 1975 and 1976 22c.u. models (here in Europe) was minimal, and a lot smaller than (i.e.) the 1968–>1969 ones.

                    The differences in 1959-1967 (as I know ) are also only in upper cover shape. Technically I noticed only the new AC fuel pump in 1960 and the fixed carb high speed jet in 1963.

                    The major FD evolution IMHO is in 1967-1970 era.

                    Between 1967-1968 OMC renewed the leg (with internal exhaust pipe and external squared design), the gearcase (squared design) and the prop (coming from 9 1/4×11" to 9×10") ,

                    The 1969 18/20hp P.H. is completely different from 1968. OMC changed carburator (completely, not only venturi size) intake manifold (larger carb flange), condensed fuel circuit (with external hose from intake to to bypass cover). They also made the 25 hp model with the same innovations and different Cyl head, rods, pistons and crankshaft

                    Last (estetical) big change came in 1971: changed the midsection ( carrying handle, steering housing and dumper covers) and the upper cover assembly.

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