1958 Johnson RDS-20 35hp

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  • June 2, 2026 at 6:01 pm #320644
    firedome
    Participant

      Hi all;

      Just got this motor on an unusual 1958 16′ Oasis Craft Sirocco (Boise Idaho made for 3 yrs, sold to Owens).

      The motor is locked up, hope to free it, but may be looking for an equivalent parts motor for it. I’ve had a few ’55 to ’64 OMC big twins.

      What years would have the same block & electrics for an easy swap? I know a ’58 Lark is pretty much identical except for trim/color.

      Cosmetics need work, who makes the correct paint now that Peter in Ontario has retired?

      Does anyone repro the (or know a source for good used 3 plastic badges on the front & rear of the cowl?

      Thanks in advance for any and all help.

      Roger in Colorado

      June 2, 2026 at 6:13 pm #320647
      firedome
      Participant

        PS:  is there any significant difference other than trim between the RDS-20 and  RD-19c?

        The parts catalog for the RDS-20 seems hard to source but the RD-19c is fairly plentiful.

        Same for ’58 Lark vs Big Twin.

        thnx,

        Roger A.

        June 2, 2026 at 7:04 pm #320649
        Don
        Participant

          US Member

          Yes, there are many differences between the RDS-20 (super quiet model), and the regular RD-19C models.  Keep looking, the proper parts manual will turn up…

          June 2, 2026 at 8:18 pm #320651
          JACQUES
          Participant

            drop the GC  to see if the lock-up goes… pull starter may be locked up…did you try in neutral in case there is a safety mechanism  or  throttle set to high    see page 313 from the bible….?

             

            to service…… download this FREE  bible book .. it covers all your needs  store on your PC  or print locally

            https://www.socalaomci.com/library/johnson_service_manual_10th_edition.pdf

             

            Joining AOMCI has priviledges 🙂

            June 3, 2026 at 12:22 pm #320713
            outbdnut2
            Participant

              US Member

              In 1958, the 35 Lark and the 35 Johnson Super Sea Horse you have  became the first 35s to have a  fuel pump, a thermostat and the super-quiet lower.  Much different powerhead and cooling passages than the big twins, and standard Johnsons of the same and past years. Note in 1956-57, the Lark and Javelin was only a fancy outer shell, but that all changed for 1958. The 58 Lark and Super Sea Horse are similar inside but have different cowl mounts.  The powerhead and lower is very similar to the 1959 35s (all OMCs) and the 1960 -61 40 HPs, but those have one-piece fiberglass covers.  In 1962, the 40s got a total redesign of the crankshaft and related parts to make them more robust – you can tell these 40s by the much bigger nut on top of the flywheel.

              Dave

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              Sam M.
              June 3, 2026 at 6:20 pm #320767
              firedome
              Participant

                All good information, many thanks to you all.

                I’ve had a 1955 Big Twin 25 (manual start), a 1962 Speeditwin 28 electric,  and a 1963 Lark 40 over the years… great motors all.

                It’s my feeling the OMC big twins from early ‘5os was one of the best big-ish motors ever made by anyone. I’ve had 6  x ’58 to ’76 OMC crossflow V4s and 3 x 3 cylinder OMC inlines and love those as well, but the big twins are my favorite.  We could ski behind our 25 hp  E-rude on our little plywood ’58 Broadwater 14’ runabout “back in the day”!

                I’m aware the the ’58 Super Sea Horse and ’58 Lark were essentially the same excepting the cowl & cowl pan, and trim/color. So I  ordered a ’58 Lark Parts manual which will work fine in the meantime since can’t find the Johnson one for less than 4 times the price!

                Any info on who sells the correct paint colors now?

                I did source the 2 front plastic cowl emblems, but still need the rectangular one for the rear.

                The boat is an unusual one that came on a ’58 Tee Nee trailer with the cool “pontoon” shape wheel fenders with aerodynamic taillight.

                The windshield has a unique fiberglass frame rather than the usual plexiglass with aluminum trim.

                I have located a correct potential parts motor too, a 1958 Lark, if needed.

                Thanks again to all.

                June 3, 2026 at 10:58 pm #320808
                outbdnut2
                Participant

                  US Member

                  For paint , go to https://vintageoutboardpaint.com/

                  Those old 25s/1956 30/1957-59 35s all would pull two skiers out of the water if they weren’t really heavy people.  Lots of low end torque.  the 35s and 25s from about 1976 on up will struggle to do that, and forget it with the 4-strokes, but all these newer models use less fuel.  When I was a teen, the neighbor and I at the cabin used to ski double behind their 1958 18HP on  a decked, 14′ Alumacraft model F.

                  Dave

                  June 4, 2026 at 2:01 pm #320902
                  firedome
                  Participant

                    Torque for sure!

                    Our neighbors at the lake the Stevens bought a 18 or 20′ Kayot pontoon in’58 with a Johnson 50 V4. They’d ski behind that big thing too! Those early V4s were real torque monsters, but not fast on a light boat with that big gear case.

                    June 5, 2026 at 11:08 am #320997
                    seakaye12
                    Participant

                      US MEMBER PAY BY CHECK

                      Marine Engine seems to have the Parts Pictorials and listings for both the RDS-20 and the 19.

                      https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1958&hp=35

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