Benefits of overboring cylinders?

[zul8tr]

All I said in my post above would not practical for aluminum hulls.

[Mark75H]

I appreciate the help guys...I'll check that off my list of possible things to do.

I'm running this motor on a 15 foot aluminum duck boat that gets beat around pretty good. Working on the bottom is really not an option. All the work would disappear after the first log jump.

That really changes things. I doubt there is ANYTHING that you can do to your motor (other than selecting the best prop) that will help at all.

A smooth straight bottom is the first thing for speed. If you can't keep the bottom smooth and straight if you want to go faster you need to consider if you have any possibility of using a much larger motor.

[BRzuki]

A larger motor is out. My motor is a 25 yamaha 3 cyl. I've seen noticable gains already from larger carbs, exhaust work, intake work, and even plugs. Just trying to exhaust all options to get the most out of this motor.

[fs5]

there must be some gain doing it.i've been thinking about it myself.
theres guys over here that fit the twin cylidner sleeves out of a 40hp 2cyl tohatsu into the 3 cyl 50hp.to up the displacement.
has anyone ever tried it on a stock motor?
you'd think it would have to raise the compression a bit?