1969 25hp Evinrude Low Speed carb and flywheel torque

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  • June 22, 2017 at 2:42 pm #7396
    mas
    Participant

      US Member - 2 Years

      Hi,

      I’m helping a friend with his 1969 25 hp Evinrude. I’m rebuilding his carb and checking over the magneto. I’ve got lot’s of factory service manuals…but nothing that new. I do have the parts diagrams from marine engines….so a couple of questions:

      What is the initial low speed setting for the carb?

      What is the torque for the flywheel nut?

      I did notice a "plastic seat" for the low speed needle in the rebuild kit…first time I’ve seen that. Anything else special I need to look out for?

      Thank you,

      Mas

      June 22, 2017 at 4:11 pm #60132
      amuller
      Participant

        The torque spec is 40-45 ft lbs. I’ve been working on one of these. (Need a hood for a 69).

        These motors are highly stressed at 25 hp. If there is any question about the fit of the flywheel to the crank I would lap.

        There is an OMC manual for these here: http://boatinfo.no/lib/evinrude/manuals … .html#/588

        June 23, 2017 at 12:07 am #60149
        mas
        Participant

          US Member - 2 Years

          Thanks…I’ll look over the fitment of the flywheel.

          Also, what is the best way to install the low speed plastic seat. My first thought was to seat it with the needle…but I’m thinking better of that. The taper of the needle may cause the plastic to crack. I bet Evinrude made a special tool…something with a shoulder??

          Also, any recommendation of the initial carb setting 3/4?

          Mas

          June 23, 2017 at 2:02 am #60161
          amuller
          Participant

            Are you talking about "314166 — BEARING, NEEDLE VALVE. ALSO AVAILABLE IN CARBURETOR REPAIR KIT – ORDER PART NUMBER 383892 (1 required per assembly)" There is a pic on Marine Engine and it does look like a plastic bit. I don’t know a thing about it. The manual I linked above might have some info in the carb section. Offhand It doesn’t seem that plastic would have adequate dimensional stability for that application.

            June 23, 2017 at 3:39 am #60163
            mas
            Participant

              US Member - 2 Years

              Yup…that’s what I’m talking about! It’s plastic!

              Mas

              June 24, 2017 at 4:33 pm #60247
              fleetwin
              Participant

                US Member - 2 Years

                http://www.marineengine.com/parts/johns … etor+Group
                #28 is the plastic needle valve cup/seal. #29 is the friction washer that keeps the needle from spinning freely.
                These carbs had not fiber washers and collar nut on the needle valve, these items for two functions. First, the fiber washers formed a seal that keeped outside air from being sucked into the low speed circuit through the needle threads. Secondly, tightening the collar nut jammed the fiber washers against the needle valve so it won’t just spin freely.
                I have wondered why the original design changed, and just asssssumed it was a cost savings. But, I have had a change of attitude, remembering that the original 55hp 3cyl models shared this carb body, and all that crazy linkage linking the needles together so all three needles could be turned together using that adjustment knob on the lower motor pan. You would never be able to turn the needles together if all three carbs had the old style fiber washers and collar nuts.
                So, you want to make sure #28 is in place, or the engine will run lean at low speeds….

                June 24, 2017 at 8:43 pm #60256
                mas
                Participant

                  US Member - 2 Years
                  quote fleetwin:

                  So, you want to make sure #28 is in place, or the engine will run lean at low speeds….

                  I’m finding it difficult to ensure that this in place…I’m sure OMC had a special tool?? I ended up using the back end of a drill bit to line it up…who knows if it is seated properly. I know that it is square from visual inspection, but unfortunately I did not take measurements to measure depth of seating.

                  Mas

                  June 25, 2017 at 3:26 pm #60301
                  fleetwin
                  Participant

                    US Member - 2 Years

                    I agree, very difficult to do both, verify its presence, and properly seat a new one….I think the easiest way to install a new one is to mount it on the needle and gently thread both items in place together.
                    There is no special tool for removal, most just sharpen/bend the end of stiff wire (such as control cable core wire) to snag the bushing/seal and pull it out….
                    Am hoping everyone here will come up with some slick ideas to verify its positioning/install/remove it….
                    I’m thinking the best way of knowing if it is in place/properly positioned is if you have difficullty trying to thread the needle in, or the engine idles lean no matter how far out the needle is set….

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