Fuel gauge stuck

tookielee · Nov 4, 2020

MT-125: My fuel gauge has quit working, it's stuck on full.
While the tractor is still in warranty, I'd rather not lose a bunch
of time with it at the dealer for something so minor.
Any suggestions of where to start to look?

Supraman0614 · Nov 4, 2020

Check the wiring from the tank sensor to the gauge. Alternatively, if there is a float in the tank, is it hung up on something? Did the filter basket drop into the tank?

LScraig · Nov 5, 2020

The fuel gauge on my MT125 remains on full until I've used about 3 gallons of fuel. Maybe nothing is wrong with your gauge. I've read on other sites that this is common on this model.

Avenger · Nov 5, 2020

I'm assuming you have used up some fuel, to notice the lack of movement in your tank?

Check the wiring and look for fuses. Your other gauges work? Not sure if your tractor has separate fuses or one for the gauge cluster.
Second, your float might be stuck. Jostle the tractor the best you can, see if that will un-stick it. If not, then you probably need to drop the tank to get to the float. I'm not sure on your particular model. If you can tell that your float is down, and your gauge still reads full, we will need to start looking at other things. What those are exactly? I'm not sure yet.

You may need to get a service manual. Here is a snipit from mine about the float and what resistance by position it should be at. Something to check for your machine.

Also, mine uses a stepper motor to move the gauge. If your tractor also uses this motor, might be the motor is bad.

Hope this helps.

tookielee · Nov 5, 2020

Bush hogged for about 4 hours last week, never dropped - it used
to move to around half by that point. It's a low priority, just wondered
if someone had an easy check. I'll try to get to it soon, and I'll repost

Leejohn · Nov 5, 2020

Easy check is to unhook then sending wire and if it stays on full that wire is grounded.

RickB · Nov 5, 2020

Leejohn said:
Easy check is to unhook then sending wire and if it stays on full that wire is grounded.

Then if you have easy access to the sender, take it loose and listen for the float to drop when you first move the sender mount. If the float is hung you might hear it release. If so, then remove the sender and carefully bend the float arm away from the tank wall. Of course you could have a failed sender rheostat. That would require a new sender.