MPG or GPH

[JohnB]

Flo scan is the way to go. It will pay for itself in 20 trips or less. You can change the trim/rpm/tabs on the boat to get the most economical speed based on load in the boat and sea conditions. If I run mine at 4400 rpm, I am at about 30 mph getting 1.6 mpg, if I bump it back to 3800, I run about 26 mph, but get close to 2 mpg. On an average trip, I run 100 miles, the difference is over 12 gallons, at 4 bucks a gallon, thats 48 dollars, by just slowing down 4 mph or so.

[peterb]

Like JohnB said, once you have a device that gives you realtime feedback it's amazing how the little things add up (such as tweaking the tabs and finding the optimal speed range, which may be different than the engines suggest).

With my boat the RPM's and MPH speed are pretty close to one another (except at the top range when I am going 57 MPH at 5,300 RPM's).

I have twin Yamaha 0X66's and average between 1.6 and 1.8 Mles per gallon when cruising. If I bump the engines to above 4,200 RPM's the engines purr like kittens but start to swill the gas. I would not have not known this if it weren't for the fuel mgmt. system.

[3rdday]

take a 1,2 0r 5 gallon reserve tank. Drop your fuel line into that and run it dry. Use a GPS to log your miles.
You can try a 1 tank on cruise, another on WOT, etc.