Honda 25 HP.

[Steve watts]

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

 

[Sea Rider]

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

 

[Alumarine]

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.