The Electric Fuel Gauge is a 12 Volt DC gauge with a spring toggle switch that is normally OFF. Move the switch to ON and the fuel gauge is ON.
There are 2 inspection ports on top of the stainless steel fuel tank in the engine room. The fuel gauge sending unit is installed on the forward inspection port. There are two wires going to the sending unit from the fuel switch/gauge. Do the following tests:
In the engine room:
- Near the top of the fuel tank, the two wires from the switch/gauge are spliced to the two wires from the fuel tank sending unit with insulated Male/Female Spade Connectors. Pull these connectors apart.
- Using a voltmeter on the two wires which are coming from the switch/gauge measure the voltage with the "fuel check switch" near the gauge in the OFF position...it should read 0.
- Next measure the volts on the same wires with the switch ON...it should read about 12 Volts DC.
- If this checks out, everything is good except possibly the stem and float part of the measuring system...but 1 more test:
- Reconnect the two wires, except leave the plastic insulator pulled back to allow for Voltmeter probe contact.
- Using a voltmeter on the Spade Connectors, measure the voltage with the "fuel check switch" near the gauge in the ON position.
- If the tank is full it should read 12 volts...if it is half full 6 volts, it it is 1/4 full 3 volts.
If all of above checks out, the problem is with the float and stem...and could be something simple like the float is stuck.
- Disconnect the insulated Male/Female Spade Connectors.
- Remove the 8 bolts on the inspection hatch on the fuel tank.
- Take care that the rubber gasket does not fall into the tank
- You will have to slightly rotate the plate as you pull up exposing the approximately 1 meter stem and float.
- If your problem is visual, possibly you can repair.
- If it is not visual, you will need to take the stem and float to a shop that specializes in fuel tanks.
Hope this helps.