MF 165 Fuel Gauge Problems

[RCWa MF 165]

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I have a 1970 Massey Ferguson 165 Diesel with an alternator. I have been working on the Fuel Gauge. I have purchased a new Gauge and Sending Unit from a MF dealer. I cannot get the gauge to work. The gauge is powered from a terminal on the external Voltage Regulator. The regulator has 4 terminals, F, 1, 2, and 3. The Fuel Gauge is supposed to be powered from the Terminal 3. I do not have voltage at Terminal 3, when the tractor is running. The Voltage Regulator is new from the MF dealer along with a new Alternator, non MF. The gauge will work when power is supplied from another source other than the Voltage Regulator. Anyone have suggestions on why I am not getting voltage to the gauge? Anyone have a wiring diagram for a MF 165 Diesel with Alternator? The diagram in the MF Manual is for a Generator.

 

[Jim.ME]

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I have a 1970 Massey Ferguson 165 Diesel with an alternator. I have been working on the Fuel Gauge. I have purchased a new Gauge and Sending Unit from a MF dealer. I cannot get the gauge to work. The gauge is powered from a terminal on the external Voltage Regulator. The regulator has 4 terminals, F, 1, 2, and 3. The Fuel Gauge is supposed to be powered from the Terminal 3. I do not have voltage at Terminal 3, when the tractor is running. The Voltage Regulator is new from the MF dealer along with a new Alternator, non MF. The gauge will work when power is supplied from another source other than the Voltage Regulator. Anyone have suggestions on why I am not getting voltage to the gauge? Anyone have a wiring diagram for a MF 165 Diesel with Alternator? The diagram in the MF Manual is for a Generator.

I don't have the MF 165 diagram, but most electric gauges on those were powered by an oil pressure switch which was mount to a Tee fitting at the back of the mechanical oil pressure gauge.

 

[RCWa MF 165]

I don't have the MF 165 diagram, but most electric gauges on those were powered by an oil pressure switch which was mount to a Tee fitting at the back of the mechanical oil pressure gauge.

Thanks for the info!

 

[miangus]

As Jim mentioned powered by the oil pressure switch, so it wouldn't work unless the engine is running and has oil pressure.

 

[miner09]

The oil pressure switch controls the generator after oil pressure comes up. Don’t know if it makes fuel gauge work. I would think it’s powered from another source. Maybe from key switch.

 

[Jim.ME]

The oil pressure switch controls the generator after oil pressure comes up. Don’t know if it makes fuel gauge work. I would think it’s powered from another source. Maybe from key switch.

Most MF diesels of that vintage had a start switch to crank the engine and a pull cable fuel stop. There was no "ignition switch" that powered gauges or accessories. According to the wiring diagrams, common to the 100 series, the oil pressure switch (mounted at the back of the oil pressure gauge) controlled only the fuel gauge on generator equipped tractors. On alternator equipped tractors it controlled the fuel gauge and provided excitation power to the alternator. Lights were powered from the voltage regulator for generator tractors and the ammeter when alternator equipped.

 

[Ron(Ont)]

I recently repaired mine. It had been modified to have 12 volts from battery feed a SPST toggle switch then on to the fuel gauge. I left it that way so you can check the fuel level with the tractor engine off. I bought a Marine sending unit on amazon that worked well. It is a very simple design.