The fuel gauge on my JD 310c has never worked since I bought the machine. I've had a couple close calls with running out of fuel, so I decided to try and fix it. I thought I'd start by just replacing the fuel gauge first because I assumed replacing the sender was going to be a bigger job. I bought a fuel gauge that was very similar but not a direct replacement for the OEM gauge because all the replacement parts I could find for the JD part # were more that $400, which is ridiculous for a fuel gauge. Anyway, I installed the new fuel gauge but still have an issue. When I connect both the battery wire and the sender sensor wire to the gauge the fuel level reads fully empty. When I disconnect the sensor wire from the gauge the fuel level reads 100% full. The tank is actually full but I know it can't be reading that it's full if the sensor wire from the sender is not even connected to the gauge. So I suspect that it's the sender that's bad, but I thought I'd post something here to see if I could get anyone to corroborate my theory before I order a sender and go through the hassle of replacing it. Is there a way I can test the sender before replacing it? Lastly, if it is the sender that needs replaced, has anyone here ever done that? I'm hoping that I can do it by just draining the fuel below the level of the sender without removing the fuel tank. Any experience here with that would be appreciated. Thanks in advance.
In my experience with various manufacturers equipment, its almost always the sender that will die before the gauge. Different mfgs use differing systems and aftermarket sometimes uses their own unique system. On older equipment the sender is basically a variable resistor which can be checked with a standard VOM to see if it is working. Some can read from low ohms to high ohms (float from empty to full), some high ohms to low ohms. The gauge will usually specify what it's measurement range is; your replacement fuel gauge may not be compatible with your sender.
Thanks for the reply, Berky. That's helpful.