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Honda 25 HP.

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  • Honda 25 HP.

    Because the spec's are the same is there a procedure to increase the horse power of a 25 to 30?

  • #2
    Welcome to Iboats,

    Why would you like to increase the HP ? If both OB's are same CC, the restrictions could be : timing advance/carb synch, carb model, reed valve plate, valves, props, etc. Upgrades costs will depend entirely if it's a 2/4 strokes carbed or fuel inyected model. Check both 25-30 HP spare parts manual and see which parts differs. The upgrade could turn into a costly one depending on how many parts need to be bought and swapped..

    Happy Boating
    Last edited by Sea Rider; September 6th, 2017, 08:25 AM.

    Sea Rider 320, 380 Sibs, 450 Rib, 2 Strokes Tohatsu 5,18 & 30 HP Proud Smokers


    • #3
      Sign up today
      Also need more info to answer your question.
      Like model numbers etc.
      Honda has made a number of 25 and 30 hp motors.

      As SR says, check parts manuals. I'd see if the cams were different.
      1980 Sylvan Aluminum 18' Sportster I/O - Mercruiser 140, Honda 7.5 Kicker, Bennett M120 Tabs
      1974 Glastron V-179, Mercruiser 140
      1984 16.5ft. Alumarine Sealark side console with 82 Merc 50
      Manitoba, Canada