If the gauge is not working then the grounding wire needs to.

Ranger bass boat fuel gauge not working. Ranger Boat Fuel Gage Problem It is one of three things. Im sure there is a spec too but i dont know. Turn the ignition to the on position and look at the fuel gauge.

If you dont know how to do any of this find yourself a technician who knows their way around gauges. Test between the positive terminal on the fuel gauge and a good ground. To do so connect the negative jumper cable to the vehicles frame and the positive cable to the fuel gauges grounding terminal.

Ill check again when I pick up the boat tomorrow. All the other gauges are functioning trim amps rpms. Check to float in the fuel tank make sure it isnt stuck.

It returns to zero when the engine is off but shows full the rest of the time. -The left side fuel gauge is not working. The easiest way to check the gauge is to pull the hose off the back of the gauge put a piece a couple of feet long on the gauge apply about 25 pounds of compressed air to it and see if the gauge reads the pressure.

If it isnt check the ignition circuit. The reading should be 12 volts. I had this happen on my bass boat it was a breaker that was tripped.

Since the thing is intermittent you need to stick your head under the console and tighten the wires. Most times thats all it is. Im not sure what it could but its not too hard to find out if you have some time pull the sender and move the float up and down measure resistance if it changes smooth that part is good.