[peterb]

I had twin 150 hp Yamaha's on a 23 footer. Top speed was about 43 or 44 mph.

I now have twin 200 HP Yamaha's. Top speed right now is low 50's.

My guess is that you can probably hit 50 MPH if you have the right pitched props and if the engines are at the right level.

Also, I am assuming that the Johnsons are carbed engines, which if so, I would guess that you may average 1.5 to 1.6 miles per gallon.