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Shaft to long.

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  • Shaft to long.

    I am the proud owner of a 1990 Mako 231 with a 2001 Evinrude 225 HP FICHT.

    I’ve spent every summer on dauphine island, Alabama for the past 6 years wishing I had my own boat.

    “My wife said is be careful what you wish for”

    I’m new to (saltwater boating) and this boat is my project I’ve dreamed about for years.

    The boat is very good condition overall. There is a little sagging in the gas tank cover that and a few cracks in the gel-coat that I will be repairing. I plan on painting the boat with awl-grip but I need to fix the motor mount problem first. The boat has a jack plate installed and it is at is maximum lift of 7+ inches, and the motor shaft still seems to be to long. The higher it sits on the jack plate the more pressure it puts on the middle of the transom (acts like a pry bar). There is a bow in it now. Its looks like if my transom was full height this outboard would bolt right up.

    My question is how do you calculate outboard motor shaft length for a boat?

    Where should the lower unit of an outboard set in the water in relation ship to the keel?

    If this motor was sized for a full transom can I still install it on an engine bracket with swim platform?

    (I would be happy to post pics if I could figure out how)

    Any help will be greatly appreciated

    Lloyd Holland[br]Auburn, Alabama.

  • #2
    To calulate transom height, measure from the top of the transom to the bottom of the boat. Use the mako link on the home page to find more info on your boat. Your motor must have an XXL shaft. If you are going to run the setup as is, you should reinforce the transom where the motor bolts up(top). A piece of 3"-4" angle aluminum should work. This distributes the weight across a broader area. I also would suggest supporting the motor(putting a block of wood under the skeg) while the boat is not being used. I think you should be able to find a bracket that fits your needs. Good luck, Tony.
    79 Mako 23[br]85 Wellcraft 18 fisherman[br]Hammond, La.


    • #3
      Spectrout77 (Tony)

      Thanks for quick Response. I called D&D marine this morning they are open 9am to 9pm 7 days a week and got the scoop.

      My boat should have had a 25” shaft motor not the 30”, which I have now.

      Not bad news.

      I was planning enclosing my transom and installing an engine bracket. Don at D&D suggested installing a RT-7 (twin eng bkt) with swim platform for extra flotation, and mounting the new bracket for a single 30” shaft motor.

      I plan on keeping this boat for very long time and I see Twin Honda 4 strokes in the future. Don said if I repower boat I would need to buy two 25”shaft motors mounted 14” off of centerline. He said I would have plenty of adjustments with the new motor mounts to get proper height adjustment.

      What Don told me sound correct and addresses my 30”shaft motor I have now, the extra flotation I want and the possiblity of twins 4 strokes when the Evinrude give out or leaves me stranded in the big pond.

      Let me know if I am missing any thing.

      Great site


      Mako 231
      Lloyd Holland[br]Auburn, Alabama.