1955 Johnson RD-17 Test Prop

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  • August 20, 2025 at 3:18 pm #299114
    William Bairstow
    Participant

      Hello All.
      I have a 1955 RD-17C 25Hp and I’m at the ‘fire it up’ stage of the project.  I have a 309864 test prop but I understand its incorrect for this motor.  I haven’t been able to locate the correct prop, 388295 test prop.   from my research I believe the prop is for later models and wont provide the correct resistance resulting in higher than desired rpms while tuning. Could I ask the general audience on thoughts regarding this topic?  I usually just get it close, then tune it on the water.  It would be nice to have it more accurately tuned before I get on the water.
      Thanks in advance!

      August 20, 2025 at 10:50 pm #299130
      Tubs
      Participant

        Most will tell you that there is no substitute for having a motor on a boat when dialing in the carb settings. However running them in some type of test tank, for a considerable amount of time, may reveal an issue before you make that trip to the water. 

        A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

        August 21, 2025 at 2:44 pm #299147
        William Bairstow
        Participant

          Thanks, Tubs.

          Agreed.  Time and back ache!

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