Upgrading a outboard motor

Discussion in 'Bubba's Outboards' started by tntitans21399, Dec 17, 2007.

  1. tntitans21399

    tntitans21399 New Member

    Messages:
    82
    State:
    Tennessee
    I bought my first boat last jan., & it came with a 1972 55HP Chrysler outboard. I don't think I am getting all 55HP out of even thou the compression level on both cylinders were great. It pushes me (by myself) at about 21mph, it is a 16ft fishing bass boat, but if someone else is in the boat it drops down alot. So that's why they upgrade.

    My question is. I was talking to find who has been boating for years, and he said I should look at a new engine (90's) same 40-50HP would be better then a 80's 75-85HP. He said I would be better to get a newer engine with less HP then a older with more HP. He said the newer engine may have less HP but it actually perform about the same.

    I was wondering what your thoughts were?
     
  2. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Probally what he is trying to get at is the way outboards are rated now.
    They are horsepower rated at the prop not the crank.
     

  3. tntitans21399

    tntitans21399 New Member

    Messages:
    82
    State:
    Tennessee
    Which would you pick? The older more HP or the newer less HP?
     
  4. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I wouldnt go less then I had. True, the newer motors are probally lighter and rated differently but its not that BIG of a difference.
    If my boat was sound in its workings and I knew the motor I had was putting out like its supposed to and I didnt feel it was enough, I would size up.
    Just dont be disappointed if you increase the engine by 20 HP and see little difference.

    Horsepower isnt always the answer to speed. Weight can be and is always in the equation.
    At some point the horsepower to weight ratio increases substantially to make up for the weight you are adding in horsepower and fuel.
     
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If you go with a older motor in the 75 to 85 h/p then you are going to add a bunch of extra weight. If you want more h/p then my suggestion would be to go with a 3 cyl 70 h/p in the late eighties or ninties.
    Like mark said you need to look at the set up before you will see much of a difference. It needs to be dialed in to the boat in other words.
    I have a 17 footer with a 1972 50 h/p and it pushes that boat with three good people and all the gear at 30 mph by gps but I dialed it in so when you decide what you want to do then post here and we will help you set it up.
    The motor needs to set at the right height on the transome and then choose the right prop for optimal performance.


    What brand of boat do you have and what year. It may be suffering from water logged foam being to heavy to push or the prop could be all wrong.
     
  6. tntitans21399

    tntitans21399 New Member

    Messages:
    82
    State:
    Tennessee
    I have a 1972 16ft Terry Bass Boat, and I have heard from some people that Terry Boats were made solid which makes them a little on the heavy side. I really like the boat and the layout so I don't want to upgrade the boat just the motor.

    I have came across a couple of motors before, didn't have the funds at the time, from a 60HP up to a 85HP. And if a 60HP could do what I need it then I that would be fine & don't have to get a 85HP, but I wouldn't want to spend the time & money on a 60HP to find out it does the same as my current 55HP. But I can only guess that a newer engine with the exhaust out the prop with a bigger prop would make a big difference, even with the same HP. I'll try to add 2 pictures of my prop vs a newer prop type.

    The first pic is what is on my boat, and the newer type (where the exhaust comes out the prop) is the black one. The picture of my prop isn't the greatest picture, but it gives you a idea on what I'm talking about not only upgrading for a newer stronger engine but also more of a prop to push the boat.
     

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