massey fuel gauge

[Mr bill p]

I have Massey 165. I can not get the fuel gauge to work. I have replaced the fuel gauge, sending unit, voltage regulator.The oil pressure switch is ok. What should the voltage be coming out of the voltage regulator? How do I check the sending unit?

 

[DaButcher]

You should have battery voltage to the positive side of the fuel gauge and the sending unit wire on the other side. Sending unit is checked with a ohm meter, I don't remember for sure but I'm pretty sure when the sending unit goes to ground the gauge reads full. A quick check of fuel gauge working would be to run a jumper wire to ground on the sending unit side with the oil pressure switch closed. I added a chassis ground from a screw on the sending unit to assure the tank was properly grounded, the original setup had a piece of metal under a screw and digging into the tank.

Have you checked the wire from the sending unit to the gauge? Mine had rubbed in to and was replaced.

 

[The kid]

I have Massey 165. I can not get the fuel gauge to work. I have replaced the fuel gauge, sending unit, voltage regulator.The oil pressure switch is ok. What should the voltage be coming out of the voltage regulator? How do I check the sending unit?

Here's a simple drawing I made when I replaced/rewired mine.

 

[Mr bill p]

Thank you for the information. I did every thing you suggested, the sending unit checked out fine,.When I put battery voltage to the positive side of fuel gauge the gauge jumps to full. with the sending connected or not connected. Im thinking bad fuel gauge.

 

[banjodunn]

G'day your gauge may be ok but your wire to the sender unit may be shorted to earth have you got an ohm meter to check this?


Jon

 

[The kid]

Thank you for the information. I did every thing you suggested, the sending unit checked out fine,.When I put battery voltage to the positive side of fuel gauge the gauge jumps to full. with the sending connected or not connected. Im thinking bad fuel gauge.

If you put voltage to the gauge (mounted in dash) and it jumped. That would indicate it's good. Not bad. It's not a good idea to peg out the gauge that way but it does indicate the coils in the gauge are good. Now to check the rheostat on the tank sending unit, you would have to remove it to inspect it. In most cases the the wiper usually cuts the wires in two thus an open rheostat. If you remove it. you can ohm the sending negative to tank mount. Positive to center terminal on the sender. You can raise the float up and down to vary the reading on the ohm meter. If that is working, you either have a power supply problem or wiring problem. If your sending unit is bad, which is what I'm guessing. Be sure to order the correct ohm range which effects accuracy or the fuel gauge. -kid