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Outboard Engine Weights

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  • Outboard Engine Weights

    Can anyone tell me the weight difference between a 1989 Mercury 50 and a 1973 Mercury 115 Inline 6? Bought a bigger motor for our pontoon and am curious about how the transom will hold the bigger motor.


  • #2
    Re: Outboard Engine Weights

    Whats the max.hp rating for your toon?If its 115hp or greater and your transom is soild,then go ahead.If transom is suspect or its over the max hp. rating,then id say no.And one more thing,2 strokes are meant to be ran WOT.If that 115 is too much for your boat and you plan on running 1/2 throttle all the time,youre not going to be doing it any favors.


    • #3
      Re: Outboard Engine Weights

      Thank you for the reply. Do you know where I can find what the max hp is for the toons? I looked all around the transom and cant find anything? I took it to our welder to see if he thought it should be reinforced and he seemed to think it was fine the way it is, but I wanted to see what the weight difference is we are talking about. I have manuals for both motors but I can't find it there either.

      Thanks again

      Not sure if this matters but the pontoon is a 1980 28'


      • #4
        Re: Outboard Engine Weights

        There should be a plate somewhere inside your boat that states the maximum person capacity,weight capacity and max hp capacity.It is required by law on all boats.If it doesnt have one,you need to contact the boat manufacturer and/or do some searching to find out the maxes.Im sure there will be people come on here and say just do it or dont worry about the plate or what not.You can do whatever you wish.Good luck.


        • #5
          Re: Outboard Engine Weights

          That inline six weighs about 300#. I would think that 50HP motor is in the 200-220# range.

          Are they both 20" shaft length?


          • #6
            Re: Outboard Engine Weights

            Dry weight on that 89 50HP is 188 pounds according to my sources. That makes for a hefty weight difference between the 50 and the 175. From what I've been told, the max hp of a boat is all about weight and manufacturers are somewhat generous in their max ratings. It's a marketing point...

            You can put the max rated motor on a boat, but you generally get a little better performance with something at about 2/3 or so than the max rating. You lose a few mph, but you run more efficient because there is less weight bogging the boat down. It also frees up some available weight capacity for carrying people or gear.

            You should be able to get hold of the manufacturer of the boat to see what the max weight, person, and HP capacities are. That'll let you know how much you can really drop on there.

            Either way, if you do put the 175 on there, you should consider shifting some weight to the front to balance things out.


            • #7
              Re: Outboard Engine Weights

              When did the 175 come into the picture ?


              • #8
                Re: Outboard Engine Weights

                Um... Ooops... I meant 115...