Re: New forum member and fuel usage question!
General rule of thumb on 4-stroke fuel consumption is: Horsepower / 11 = gallons per hour at WOT
This isn't exact, but it's pretty close for a carbureted engine. EFI sometimes is a little more efficient (divide by 11.5). With 2-stroke outboards, divide by 10 (don't want to leave anyone out here
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For example, if your engine is the 250hp carbed 5.7, your wide open throttle fuel consumption will be about 23 gallons per hour (86 liters per hour on your side of the pond).
As for how much you'll actually burn at cruise (and fuel consumption per kilometer), that's going to vary based on about a hundred different factors. Maybe you could calculate it exactly, but you'd need a really sharp pencil and a lot of notebook paper.
For a closed bow runabout like the Futura, I'd plan on about 3.5 miles per gallon (about 67 liters per 100km). Might be a little more or a little less, but that's a close estimate IF the boat is running well AND you run at an economical cruise speed.
