Boat gas Guage not working

[Adshafer]

Hello all, hope all is going well with everyone. I have the last thing on my bass boat to get fixed and it seems to be the most simple one and that’s the gas gauge. Can’t seem to figure it out. I know many say to not trust it but I would like to at least have it working lol. Regardless here’s my issue, I turn on my ignition switch to run and my gas gauge instantly goes to empty. After switch it off it slowly goes back up to a quarter of a tank(my tank is full right now). I have jumped my sender wire and ground wire to see if it goes to full and it does so I have grounded it out to see if the gauge is okay and it seems to check out. I have now went to the extent of buying a new sending unit and that has proven to not fix the issue. Any suggestions would be appreciated!

 

[alldodge]

switch it off it slowly goes back up to a quarter of a tank

No power to the gauge and it goes to 1/4 would tell me the gauge is the problem. Disconnect the wires and see if it still goes to 1/4

 

[Adshafer]

Disconnect power and ground then to see if it still goes to 1/4th?

 

[KM7]

I have a similar problem: 92 Four Winns Horizon 200, fuel guage shows 0 when power is off. (So far so good) With power on, guage will read zero when I have a less than 1/2 tank or so. With more that 1/2 tank it is better but sometimes jumps around zero to 1/2. I have replaced the sender unit in the tank and cleaned all the connections at the tank. Sill jumpy reading or no reading.

Any suggestions?

Also working on an open fuel tank is dangerous. especially with electrical connections. How do I do it safely?

 

[alldodge]

Would be best to start another thread

Also working on an open fuel tank is dangerous. especially with electrical connections. How do I do it safely?

On the safety question, set up a fan away from the tank and have it blowing on the open tank area. Also make or break any connections before turning ignition back