We hooked all three gauges to the fuel ûline of a 150-hp Evinrude FICHT engine, ûthen burned 10 gallons of gas to find ûeach one's accuracy.

We enjoy slamming down the throttle once in a while and running wide open just as much as the next guy. But this summer, our 150-hp outboard rarely saw WOT (5000 rpm).

Why? Gas is too darn expensive—$2.12 per gallon at our local fuel dock. Skyrocketing prices have forced us to become more aware of our engine’s most efficient rpm settings.

In general, outboard motors get their best mileage when running from 60% to 75% of their rpm range, which is usually from 3000 rpm to 4500 rpm, says Yamaha engineer Chuck Butler. …