Very difficult to call accurately.without knowing your particular setup.
Depending on the setup it will use about 2 gph(gallons per hour) at wot
(Wide open throttle)probably 6ozs an hour or less trolling.I think I would carry an extra gallon or 2 until you know how it goes.
dunno, but I have a friend that can get about 20 miles with an F50 on a 19 sea ox on about 3 gallons. I would carry an extra gallon (in an approved container) until I got used to the range.
