seashell: you can go to the web pages of outboard motor manufacturers and get the info you are asking about. Example:http://www.yamaha-motor.com/products/otb/perfbull/performance_02.html
As I stated, if I go fishing for a day with my 25ft Mako and twin 150hp Yamahas, I plan a couple hundred US. That takes into consideration running to where I want to fish, trolling most of the day, and running back in time for cocktail hour.
PS: Pedro, 6 gallons per minute? :rolleyes: That is the kind of boat I wish I could afford.