I Just bought my second Kubota m108s tractor and after getting it home, I filled the fuel tank. The fuel gauge was at 3/8 of a tank before filling and the gauge only goes to 3/8 full after filling. Any help on where to start looking to fix it? The tractor did remain idle for about a year before I purchased it. Thanks for any help!
Kubota m108s fuel gauge not working
- Thread starter southard
- Start date
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
carefully ground sensor wire at tank, now look at gauge. It should read 'extra full'.
now remove sensor wire from tank, look at gauge, it should read 'empty'
If gauge stays at 3/8 mark, gauge is busted.....
I suspect the sensor unit itself is RUSTED and FIXED at the 3/8 level. For sure I would remove and test on the bench. They usually will read 10-20 ohm 'full' and 300-400 for 'empty', though the WSM will have the real numbers.
In any event, I'd have drained ALL the fuel from the tank..replaced filters THEN added fresh fuel. year old diesel may have algae and/or water in it......
now remove sensor wire from tank, look at gauge, it should read 'empty'
If gauge stays at 3/8 mark, gauge is busted.....
I suspect the sensor unit itself is RUSTED and FIXED at the 3/8 level. For sure I would remove and test on the bench. They usually will read 10-20 ohm 'full' and 300-400 for 'empty', though the WSM will have the real numbers.
In any event, I'd have drained ALL the fuel from the tank..replaced filters THEN added fresh fuel. year old diesel may have algae and/or water in it......
I have a SSV65 Kubota skid steer. With the fuel gage at 1/4 full and I turn the switch on the fuel gage goes to 1/2 full and drops to a bit above empty. I replace the sensor (fuel) part number V1311-51152 and reads the same. What can I due to correct this problem?
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Test both sensors using the numbers in the WSM.
curious I looked at kubcda for the sensor. it appears to be a 'float around a tube' design,so might only read 4 or 8 'zones'(each is a small magnetic switch) NOT linear like the old resistor wiper style. Would need to see the actual WSM info about it.
One possibility though is the float could be sticking to the tube.
curious I looked at kubcda for the sensor. it appears to be a 'float around a tube' design,so might only read 4 or 8 'zones'(each is a small magnetic switch) NOT linear like the old resistor wiper style. Would need to see the actual WSM info about it.
One possibility though is the float could be sticking to the tube.
Last edited:
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Constant Voltage Regulator (CVR).
The 'old skool' fuel measuring system was a battery-meter-sensor-ground.
The sensor was a low value variable resistor, whose wiper moved when the fuel level moved.
It was obvious from the start that unless the 'battery' was a constant 12 volts, that the meter reading varied NOT only on fuel level but also actual 'battery' voltage. Battery voltage could be anywhere from 9 to 14 volts depending on conditions, so the meter reads wrong.
CVR in the early days were simple electromechanical devices, giving a slow speed average of about 10 volts. In the 70s, solid state devices gave 100x better response.
Without seeing the schematic of the unit, I don't know how the fuel gauge works, though I suspect a series of micro reed switches in the 'tube' the float encircles.
The 'old skool' fuel measuring system was a battery-meter-sensor-ground.
The sensor was a low value variable resistor, whose wiper moved when the fuel level moved.
It was obvious from the start that unless the 'battery' was a constant 12 volts, that the meter reading varied NOT only on fuel level but also actual 'battery' voltage. Battery voltage could be anywhere from 9 to 14 volts depending on conditions, so the meter reads wrong.
CVR in the early days were simple electromechanical devices, giving a slow speed average of about 10 volts. In the 70s, solid state devices gave 100x better response.
Without seeing the schematic of the unit, I don't know how the fuel gauge works, though I suspect a series of micro reed switches in the 'tube' the float encircles.
I see where I can get a WSM. I'm going to pull the fuel sensor out and test for correct ohms at 4 locations.
Can also check for correct voltage in the connection that plugs into to sensor. Thanks for your help>
Can also check for correct voltage in the connection that plugs into to sensor. Thanks for your help>
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
found this.... https://www.manualslib.com/download/1727884/Kubota-M108s.html
hopefully it's the correct manaul, please let me know...
sensor is a simple resistor...
..
Float at uppermost
position
3.0 to 5.0 Ω
Float at lowermost
position
107.5 to 112.5 Ω
FYI... 'bad' readings could be a bad/crummy ground ! ANY change in resistance between 'ground' of sensor and battery -ve WILL result in bad/erratic readings.
hopefully it's the correct manaul, please let me know...
sensor is a simple resistor...
..
Float at uppermost
position
3.0 to 5.0 Ω
Float at lowermost
position
107.5 to 112.5 Ω
FYI... 'bad' readings could be a bad/crummy ground ! ANY change in resistance between 'ground' of sensor and battery -ve WILL result in bad/erratic readings.
Last edited:
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
OK, you need to start your own 'thread'... I assumed the M108s from the original post. when you 'hijack' or whatever the term is called, it's easy to confuse an old guy like me.