In the beginning I would fill the tank, run it the weekend, then fill it back up the following weekend noting the number of gallons. Then I would look at my GPS to see how far I traveled.

Once I figured out my fuel consumption it really helped when traveling on long trips because you can tell how much range you have. A few years ago when I traveled to Patchogue for the OPA races I was able to use google maps to figure out how far of a trip it was and estimate my fuel consumption. If I needed to stop for fuel I could map out my trip in the gps to make sure I don't run outta fuel.

Another example, if I only need 1/2tank for a trip, I make sure I have 3/4 tank and that's all I put in it. The boat runs better, gets better fuel economy and cruises 1-2 mph faster than if it has a full tank. It's not and exact science but it's pretty darn close! :drink:

Cruise speed..12 gallons an hour a piece x 4

Full throttle ...approx 25 gallons an hour a piece x 4

And when idiling around I only use two outer engines to save a little fuel.

My Sc5000 screen shows a burn of 30 gal. per hr @90mph in my 28 Skater with 300xs motors.Not bad 3mpg @90!!

SL 44 OL with (2) 1375 OPL EFI, cruise 95-100mph @ 4200 RPM (with conservative prop and gear ratio) 1 mpg. back it down to 80mph cruise and 1.5 + mpg (just an estimate because I never have the self control to back it down) and if you push it forward to 144 mph a 6200 rpm, then the gas guy gets paid.