How many gallons per hour should I expect to consume in a 9.9 HP Mercury 2-stroke outboard engine pushing an O'Day 25 at 4.5 to 5 knots in calm conditions? The boat is new-to-me and I'm trying to size an open storage locker under the stbd cockpit seat. It would be fully sealed from below to avoid fumes in the bilge. Our boating is on Puget Sound with 20 to 30 miles between gas stops and I'm wondering if the available space under the seat would be adequate. I'd sure like to get the gas can out of the cockpit. What has been your experience? I'd be most grateful to know.
George
George