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Motor size that won't break a transom

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  • Motor size that won't break a transom

    so i am currently restoring a boat, 89 bayliner 14' capri runabout. the boat currently has a 59 johnson 50hp two stoke. i would like to go bigger on the motor. before i stripped the old girl down i took her out to make sure the motor was sound and it is. i will more than likely run it till she is shot but it doesnt get up and scoot like i want it to and also it doesnt have power trim.

    so my question is how big can i safely go, and before you ask, the hull sicker with the rating on it is not to be found.

    transom dimensions are 1"(thickness)x25"(width)x20.5" (deepest part)x19"(sides). it's a v hull without tiller controls.

    i tried to find the coast guard formula but that has been no help as to what i did find, cause if it was true i would be rated for a 15hp motor by my math.

    any help is appreciated, and the transom is being redone with cast.
    Seadoo 96XP Full Resto (Sold)

    1989 BayLiner Capri 14' Full Resto
    (https://forums.iboats.com/forum/boat...pri-resto-help)

  • #2
    also if this is in the wrong spot, Admins please notify me and i will start it in the correct area
    Seadoo 96XP Full Resto (Sold)

    1989 BayLiner Capri 14' Full Resto
    (https://forums.iboats.com/forum/boat...pri-resto-help)

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    • #3
      also just found a guid and specs of what i assume to be my boat on here in a sticky, and it seems to be 50hp max. i will verify the model via title tonight. sorry for waisting time
      Seadoo 96XP Full Resto (Sold)

      1989 BayLiner Capri 14' Full Resto
      (https://forums.iboats.com/forum/boat...pri-resto-help)

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      • #4
        A newer(1970s - 80s) 50 Hp will run circles around the Fat Fifty, and do so on much less gas. Will weigh about 80lbs less and can be fitted with power trim, and have a choice of Props. The Fat Fifty has only two props to chose from and both are not easy to find

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        • #5
          I may keep it in the 50hp range with a newer one. And I did find out what model my boat is and it’s only rated for 50hp... to be honest I may beef up my transom, make it full width at 3/4” thick ply wood and the width it currently is make it 1 1/2 thick in that area. Then glass it all and glass her in.
          Seadoo 96XP Full Resto (Sold)

          1989 BayLiner Capri 14' Full Resto
          (https://forums.iboats.com/forum/boat...pri-resto-help)

          Comment


          • #6
            It has nothing to do with your transom design and everything to do with the width of the transom and the length. Also the design of the hull changes the factor 15hp would be the rough guess without the factor, but then you multiply it over depending on what category the boat is. I forget exactly how to do it but 50hp is adaquate for 14' for sure..

            If you overpower a boat you can push a boat faster than it is stable. Also, when you throttle forward the stern pushes down so you could potentially sink your boat. Your fat 50 probably makes 35-40hp at the prop where as a '89 boat was rated for 50hp at the prop. So you could go with an older pre 1985 60hp and get the same punch as a post 1985 50-55hp..

            You can probably get away with a 60hp Johnson/ Evinrude from the 80's- 2000's since the 60hp was detuned into 40's and 50's as well
            1961 Custom Craft Sea Ray- 1964 Mercury 650. In family since new.

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            • #7
              The standard engine on that boat when it was new was a Force 50hp engine, like has been said, there is a lot more than just the transom you have to take into account when you want to go bigger, boats are designed from the ground up to fit a certain specification that takes into account the full specifications of the whole boat when it comes to rating them for a certain HP

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              • #8
                Thanks for the reply’s y’all,

                ya I have found out my motor currently is a 70s motor, narrowing it down currently as to what exactly it is. But ya I don’t think I’ll be changing it much, just try to find something newer in the 50hp range
                Seadoo 96XP Full Resto (Sold)

                1989 BayLiner Capri 14' Full Resto
                (https://forums.iboats.com/forum/boat...pri-resto-help)

                Comment


                • #9
                  Kind of hard to mistake a 2 cylinder 50, for a V4.

                  BTW, the 2 cylinder 50 was only produced in the 70s from 1971 - 1975, in 76 it became a 55, then in 1980, a 60. There was a slight increase in Displacement in 76.
                  My earlier post should have said 'a newer 70s - 80s; 50, 55, 60 hp'
                  Last edited by jimmbo; June 13th, 2019, 02:43 AM.

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                  • #10
                    Originally posted by jimmbo View Post
                    Kind of hard to mistake a 2 cylinder 50, for a V4.
                    Man I am sooo green to outboards and google is a pain in the rear to try to identify the motor, until I found out where the model numbers are. And I am surprised it even had the tag still on it
                    Seadoo 96XP Full Resto (Sold)

                    1989 BayLiner Capri 14' Full Resto
                    (https://forums.iboats.com/forum/boat...pri-resto-help)

                    Comment


                    • #11
                      Sign up today
                      This is a great sight for engine visuals, Well OMC for sure.

                      http://boatinfo.no/lib/library.html#

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