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?

The only way to truly know how your good your fuel guage works is to run the boat so it runs out--once. Most tanks will still have some fuel in them, but not enough to get to the pick up.

Run it out close to home or close to somewhere where you can get fuel and have 5 gallons with you to make it to the pump. My guages have been fairly accurate. I can tell you, when the get on E and the needle is not bouncing, you're on borrowed time.

I was worried that's what I would have to do. One intentional mistake and hopefully never again right?

You have my next boat 28 pantera! Tough to come by in the PNW however. Still looking!

how about flo scan? is it accurate?

yup ......

That would be "had" your next boat. I sold it yesterday and its at its new home in Huntington Beach, CA with board member Dude!Sweet!

I guess I need to change my profile.

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.

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.

I intend to switch to a Centroid sender when my current one goes out or the floor rots whichever comes first.
http://shopping.rexmar.com/Merchant2..._Code=centroid

Have read about them on a lot of boat forums, can be calibrated to your tank and gauge or used with a digital gauge

They only have one bolt pattern which is a standard SAE 5 bolt pattern, that may be an issue.

http://www.centroidproducts.com/data.htm

Run the gas out until you are low on the gauge but still safe to get back to the ramp. Put it on the trailer and suck the remaining gas out of the tank and put in your truck. Once empty add 5 gallons. Put it in the water and note the gas gauge reading. Go over to the gas dock on the water and fill it up. Record the needle location every 5 or 10 gallons. Make yourself a little chart and keep in handy.

You need to do this on the water because it sits different in the water than on the trailer and the gauge reading will be different.

Rick