You need to read the manual on how to adjust them. There are screws on them to adjust and you have to to it correctly or you get your results.

Jon

Gauges on the boat are like the one in the car, 3/4 full means half empty!

The good news is that it seems I drive for free for a long time, then reality kicks in......the guage needles drop down minute by minute.

Recording flow meters work a lot better than the fuel gauges do. Floscan is the granddaddy, and has a number of options (check out at floscan.com). Standard/Horizon used to make one, the FF-41, and it's still listed on their website. Lowrance has a couple of options that are part of a multifunction system (combine with ambient water temp so you know what you're jumping into?), and there's a Navman out there as well.

If you go with an adjustable sender like a Tempo and set it precisely like they tell you to, and do not hit any baffles you can end up with a fairly accurate fuel gauge, but you also need to sweep test it before install to make sure the sender and gauge jive. (i.e. when the sender is half way up the guage says 1/2) It takes a little time and some measurement so most of the maunufacturers just wing it.