Originally Posted by Dave M (Post 2096434)

Forget about your gas guage.

I use my hour meter. Fill up tank, go boating. Next time fill up again, divide gallons by hours to determine rough estimate of galllons per hour.

I've done this over several years and always have pretty consistant GPH. When i go to the gas station I can usually tell within 5 gallons how much it will take to fill.

Originally Posted by CAVelocity (Post 2096421)

I have found with my 500EFI, that I consistently get a little better than 2 mpg, almost irregardless of cruise speed. My Garmin GPS has a built in trip odometer, so each time I fill up my 80 gal tank, I reset the trip odometer and know that I have 160 miles before I am completely out. This has worked out great for me. I have done Homestead to Key West a few times without filling up..... 150 miles via the inside passage.... and then put a little over 70 gals in.

This may not work as well with carburated motors, but it sure seems to work well for me.

Originally Posted by wrasse (Post 2095983)

My 24ft donzi's fuel gauge is nortoriously inaccurate and my understanding is that most boat's are. I believe my tank holds around 80gals. I've been too chicken to going anywhere far on the water due to fear of running out of gas. Instead, I do one day cruises around my lake and fuel up each time I go out. But I really want to go exploring places further away and be confident in how much fuel I have left.

Any suggestions?

Originally Posted by wrasse (Post 2095983)

Any suggestions?