336
All you could ever get out of the 336 was .9mpg? With my 305 loaded with 7 guys, 600lbs of ice, tons of tackle, full fuel +50 gallons extra in drums and full water I average between 1.1-1.2mpg. Now I do realize that your boat is a bit wider and bigger but I would have thought it got much better mileage than that....are the 350's that thirsty? I had contemplated putting the 350's on my boat but went with the 250's instead.....after reading this, i'm glad I decided like i did! I have the 4kw FP in mine and have never had one problem at all other than the generator shutting itself down because of low oil...which it was supposed to do...my dealer hadn't filled the oil up to the proper level and I (stupidly) took it for granted that they had an did not check it myself.....but other than that it has been flawless!! Did you figure out what the problem was with yours?