"Mario, rule of thumb on ANY o
"Mario, rule of thumb on ANY outboard (even all the hype about how much more efficient 4 strokes are)
Take the horsepower and divide it by 10 - that will give you the GPH burned at wide open throttle (if the motor is matched to the hull).
At 2/3's throttle, often referred to as "cruise speed" (usually somewhere around the 4000 rpm range), you will burn about 40-45% of max fuel consumption, so in the case of a 115, about 5 gph.
And your MPG decreases when running above AND below cruise speed. When trolling your GPH is down, but so is your MPG. Your best fuel economy is always at cruise speed.
Horsepower costs you money in gas that's just a fact of life..."
A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)