\:\) I have the 150 on my 18' outrage and it scoots it along just fine. \:D Also got the smart box but the early model where you have to scroll thru the functions. I'd opt for the new ones that display all the readings at once. Over 200 hrs and I'm averaging about 3.5 gals/hr running on plane or putting up the river.

Is'nt your boat a 24ftr? If it is you might consider the 250hp as the 150 might not be enough.