OMC 5.5 vs 6 Driveshafts

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  • January 29, 2017 at 2:56 pm #6215
    raglover
    Participant

      The lighttwins have multiplied. I have 2 cd15’s. one has no power head but the rest is perfect. The other is a long shaft, great power head but banged up lower and bad clamps.

      That one is easy, make one good short shaft cd15.

      Now, I really want a long shaft 6. My 6’s are early 70’s. I know the 5.5 has the two pice drive shaft, the 6 does not. Will the 5.5 shaft fit in a 6 hp powerhead? Plannng on dissecting this week, but could not help but ponder this morning.

      Thanks,

      Allen

      January 29, 2017 at 5:15 pm #52025
      frankr
      Participant

        Early 6hp (like 1965) had a two piece drive shaft with shock absorber in the lower unit. Long drive shaft for that is part number 376788.

        EDIT: Or are you saying your 6 does not have the shock absorber? I don’t think the crankshaft splines are different either way.

        January 29, 2017 at 7:09 pm #52044
        Mumbles
        Participant

          Six horse shafts are all the same from ’66 – ’75. Driveshafts used in ’76 – ’79 models had fine splines on the pinion end and will have to use the matching gear set, which will fit. ’65 and down two piece shafts will not work in the later housings.

          January 31, 2017 at 3:04 am #52180
          raglover
          Participant

            Thank you for the replies. I confirmed all the cranks are the same spline. Based on the answers and some looking at the parts I have all one piece drive shaft 6 horse motors.

            I am going to make my short shaft cd-15.

            The long shaft motor is very beat up less the power head and my short shaft has no power head (well it is in a box dismantled by P.O. And is shot)

            That leaves me a long shaft lower unit and tower. The long shaft lower has a badly chipped anti cav plate, functional but not dear to me.

            Would the cd15 entire lower with the two piece shaft bolt onto the 1971 tower? A Frankenstein for sure but my ultimate goal is to get an ugly but working (free) motor for a sea scouts sail boat. I cannot bring myself to put a cd15 in saltwater, so a cobbled ugly 6 from parts fits the bill….if I can get it long.

            I do not think the 6 powerhead will fit on the cd15. Bolts match but water flow is different due to t-stat.

            Desperately trying on this one but may be out of luck.

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