Fuel gauge

[surrender]

Wired my fuel gauge(old gauge but it works) and noticed that it reads empty with the key off(good, powered when ignition is on), level in tank when key is on(again good), and somewhere between empty and the real level in tank when I put the boat in gear. Take the boat out of gear and gauge will move back up to level in the tank. I guess maybe need to make sure the gauge is independant of any other gauges or systems. Maybe wire it directly from the battery switch(dont have one yet but will install). Any thoughts

 

[seabob4]

Re: Fuel gauge

Your float may be moving due to the "sloshing" around that the fuel is doing when underway.

Easy check. First, with the ignition in "run" position, on top of the sending unit, touch a wire from the center post (should be a pink or white wire terminated to it) to the ground (black) wire. Your fuel gauge should peg on "Full". Once that's determined, pull the sender (easy, 5/6 bolts and she pulls right out), and move the arm up and down, observing your fuel gauge. Once again with the key in the "Run" position. Float all the way down, gauge should read empty. Float all the way up, gauge should read full. Move the float throughout it's range and observe the gauge.

Do this and report back with your findings...

 

[surrender]

Re: Fuel gauge

All good on the sender working. This happens even with the motor off and the boat sitting on the trailer. Turn the key to on or run as you put it and gauge works. Put shift lever in gear gauge goes down. It s a resistance thing i think. The sender works on something like 249 ohms and I must have the gauge wired with it interconnected with something in in the gear shift lever. The gauge does have foutr or five other things hooked to the ground post on tyhe back.( Old boat came that way) I'll try unhooking everything except sender and ignition and one ground

 

[seabob4]

Re: Fuel gauge

All good on the sender working. This happens even with the motor off and the boat sitting on the trailer. Turn the key to on or run as you put it and gauge works. Put shift lever in gear gauge goes down. It s a resistance thing i think. The sender works on something like 249 ohms and I must have the gauge wired with it interconnected with something in in the gear shift lever. The gauge does have foutr or five other things hooked to the ground post on tyhe back.( Old boat came that way) I'll try unhooking everything except sender and ignition and one ground

The gauge works on 33-240 Ohms. Sounds like you might have a ground issue.

Tighten every one you can see or reach...

 

[surrender]

Re: Fuel gauge

The 249 was a typo. I think a ground issue also. Just got the boat and have no idea where all the wires run. I think I will run all new. Not much to it, lights, guages and a few maybe a chartplotter/fishfinder combo and radio. Can I get power for the fuel gauge from the ignition but run the ground from the gauge back to ground bus bar? Right now I wired it back the the ignition switch ground because the fuel gauge had about five grounds attached to it and who knows where they go. Some of the wire is not marine grade(the old owner had used low voltage landscape wire to bring power to some under console things). more the reason to rewire.

 

[Silvertip]

Re: Fuel gauge

Ground is ground. Attach it wherever it's available. The problem with too many grounds is that you run the risk of ground loops. Not usually an issue with standard boat electrics but can be an issue with any digital controls such as Smart Craft or other digital engine control and monitoring systems. If you happen to have an OMC electric shift outboard, the additional load of this shift system can jiggle the gauge as the added load pulls down the voltage a bit.