Fuel sender mystery

[Carverlvr2]

Ok. Let’s figure this one out…bought my 04 366 end of last year. Starboard Fuel gauge worked but read lower that port even after fill up. This year wasn’t reading at all. Dug into the engine bay and found the ground lead not attached to anything…here’s the puzzler…the small screw at the back where I assume it’s supposed to connect, has no terminal/connector attached to it. Absolutely zero place for the female spade ground wire to connect. How the sh## did it ever work at all? I put a ring terminal on the ground and secured with that small screw and it’s back to working but still reading lower than port. In fact that whole multi gauge (oil press, temp, volts, fuel) reads low and I’ve checked the ground on the back of gauge so I’m open to suggestions on that one too.

[Viper]

Usually it's a spade connector spot welded to the flange. Maybe it broke off and the previous owner installed a screw but never finished the job?

I'd look for poor or corroded connections for the gauge. If you've checked the back of the gauge and all looks good, find the bridge harness plugs and check for good clean contact pins. Other than that the readings may in fact be lower for various reasons or the gauge is on its way out. Swap the gauges from one side to the other and see if the same readings follow the gauges. That'll tell you if it's a gauge issue, accurate readings, sender or wiring issue.

BTW, the sender gasket looks like it's seen better days and may be leaking. You may want to confirm whether it's leaking or not. You can buy replacement gaskets for those senders.

[Carverlvr2]

All excellent points and I’ll try the gauge swap and go from there! And thanks for pointing out the gasket. I was so concentrated on the connections I didn’t notice the bigger safety issue looming! I had to do some boat aerobics to strip and reconnect the wire one-handed….can't wait to try to replace that gasket…lol