1959 golden jubilee 18hp

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  • June 10, 2024 at 1:56 pm #288237
    Craig Allen
    Participant

      US Member

      hey guys. I am working on a 59 golden jubilee 18hp. I have the motor running at 3/4 throttle and shut it down to slow rather quickly and shear the woodruff key on my magneto cam. it shears above the cam so i believe the flywheel is shearing it off. I have sheared 2 keys in a row. one came on the motor, the other from a hardware store. Any ideas as to what is causing my problem? Thanks.

      June 10, 2024 at 2:49 pm #288241
      The Boat House
      Participant

         

          The key is just for alignment. Is the crankshaft and flywheel taper clean and free of oil or grease. This could be causing the flywheel to slip. If that doesn’t solve your problem you would want to lap the flywheel to the crankshaft checking the fit. Tubs
         

         

         

         

         

        June 10, 2024 at 2:57 pm #288242
        The Boat House
        Participant

          .

          June 10, 2024 at 3:37 pm #288243
          bobw
          Participant

            US Member

            I agree you should lap the flywheel to the crankshaft to ensure a proper fit.   Also, I found out on a previous restoration job that a woodruff key from the hardware store may not be quite the exact fit, so better to order the correct key.    Finally, after lapping the flywheel/crankshaft tapers and installing a new key, be sure the flywheel and crank tapers are perfectly clean and dry and the flywheel nut is tightened to the correct torque of 40 to 45 ft. lbs.

            Bob

            1937 Champion D2C Deluxe Lite Twin
            1954 Johnson CD-11
            1957 Evinrude Fastwin 18
            1958 Johnson QD-19
            1958 Johnson FD-12
            1959 Johnson QD-20

            “Every 20 minute job is only a broken bolt away from a 3-day project.”
            "Every time you remove a broken or seized bolt an angel gets his wings."

            June 10, 2024 at 7:00 pm #288246
            Craig Allen
            Participant

              US Member

              thanks for the info guys . i’m embarrassed to ask, what do you mean by lapping

              June 10, 2024 at 7:23 pm #288248
              Steve D
              Participant

                From a couple previous discussions….

                Mumbles: “I do it on almost every motor I build. It gives peace of mind knowing the tapers on the crank and flywheel fit together properly.

                Get yourself some Clover Leaf or other fine lapping or valve grinding compound and apply a thin coat onto the crank taper. Lower the flywheel and turn it back and forth. Lift the flywheel and turn it 90 degrees and repeat. Don’t turn it in circles! Keep doing this until the tapers are a dull gray over their length which is an indication of the amount of contact area. Cleaning and reapplying as you go is necessary and a final clean to remove any grit and oil film is mandatory.”

                https://www.aomci.org/forums/topic/lapping-flywheel-to-crank-taper/

                https://www.aomci.org/forums/topic/lapping-flywheel/

                June 11, 2024 at 5:43 pm #288260
                Craig Allen
                Participant

                  US Member

                   

                  thanks steve, i think i have the idea of lapping

                  June 11, 2024 at 9:50 pm #288262
                  Steve D
                  Participant

                    I learned about it myself from some of those guys in the discussions.

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