Fuel gauge / sender….weird issue

[RuffleBoat]

Hello!
So I got the typical fuel gauge issue with the boat (07 bayliner discovery 192).
Found the connectors quite corroded so I cleaned them and put some dielectric grease on them. I tested the sender, it measured properly from 30 to 240 ohms or something like that. Re-connected the wires and with ignition ON (not running) , again tested well, the gauge moved from full to empty…cool , easy fix I thought.
Well when the boat is running its back to pegged on full. Engine off and just ignition, the gauge works again although fluctuates slightly on water..no biggie.
I haven’t measured but would the charging voltage while running, 13-14v , have something to do with this issue? Should I just resign mysef and get a new sender?
Orrr is it the gauge itself that could be the issue?
thoughts?
thanks

 

[Chris1956]

When the engine is on and the gauge is pegged, you are just sitting in neutral? If so, the engine charging voltage may be affecting the gauge. Make sure the grounds are good, and the sender wire is good as well.

Of course, if the boat is moving my fuel gauge shows different readings as most fuel tanks do not have baffles. Also, my 18 gal fuel tank is only 8" high. A small change in fuel level is a big change on the gauge.