speeding up my 25 h.p suzuki?

Discussion in 'Boat Repair Help' started by catfishslayer, Sep 24, 2006.

  1. catfishslayer

    catfishslayer New Member

    Messages:
    27
    State:
    Illinois
    A friend of mine was told that you could take a carborater from a 40 h.p and put it on a 25 h.p and also had to advance the timing this guy was able to get his boat to go around 30 to 35 mph on a 18 ft jon boat he also had a mercury instead of a suzuki. I was wondering if anyone has heard of doing this and if its possible and a safe thing to do.I would like to try to get alot more h.p out of my 25 h.p suzuki if possible??????
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Cheaper to buy a bigger motor. There is more to raising the h/p then just the carbs. You start changing timing without the exhaust being modified to then you are in for some over heating.

    If you want more speed the look at your set up and put a tach on it and set the motor for best performance according to how high it is on the transom.

    As for trying to super tune more h/p out of one I just won't do that but then again that is my thoughts.
     

  3. screamnclickersc

    screamnclickersc New Member

    Messages:
    755
    State:
    S.C.
    I had a 95' Suzuki 25hp 3 cylinder-it was plenty fast.I wouldn't advise mis-matching parts.The oil injection is set up for the 25's carburation,not to mention the other possilbe variables.
     
  4. Pogo

    Pogo New Member

    Messages:
    96
    State:
    North Carolina
    I don't know your engine, but carb changes on two stroke motors is an old idea.

    When I was racing motorycles (decades ago) bumping up the carb throat size was a very popular method for increasing horsepower.

    More recently, last year I installed carbs from a Suzuki 8HP (21mm) on a Suzuki 6HP (18mm) and had no problems, but from the head down, they were identical engines in all respects. This similarity extended to the carb mounting stud spacing ... the 8hp carb fit the same bolt pattern as the 6hp.

    In this case, I did not change the head, nor bore it to match the larger throat size. With a dremel tool, I merely fluted the edge of the head intake to a rounded contour, opening the intake size to 21 mm and emulating a velocity stack shape. This whole project was done with the engine still hanging on the transom and took about 90 minutes.

    Since the timing specs for both the 6 and 8 were the same, there were no adjustments to be made.

    I don't know of this sheds any light on your question, but remember that in this case, the head and carb were the ONLY differences between engines. Otherwise they were from the same parts book. If you have to rebore the head and mounting studs, I'd definitely think twice.
     
  5. screamnclickersc

    screamnclickersc New Member

    Messages:
    755
    State:
    S.C.
    Try to keep the boat light.Over weighting can hurt the performance(those sinkers are heavy!)