Fuel gauge problem

I have a 24 ft center console that the fuel gauge is not reading correctly. It has an 80 gallon tank and after using 40 gallons of gas the gauge in on empty. I have replaced the fuel meter that sticks down in the tank but that did not change anything. Any clues??

It could be the sending unit, gauge, or poor connections. Sounds like you have replaced the sending unit. I replaced the sending unit in my boat and that did the trick. I would venture to guess yours just needs some fine tuning. I adjusted mine a couple of times and never got a correct reading and gave up. It now works better than the old one and I can live with it.