520 fuel gague problem

[a bartholomew]

i need some help on how to test a fuel gegue and sender i have current to the one side of the gague the other side i have nothing but it shows empty when i turn the switch on the gague moves about a needle width all the way to E i need to knw how the system works should i have current on both sides of the gague i have about 4 gallons of gas in it the tank was empty when i started i have also hooked an extra ground to the outside of the gague to see if it would help

 

[RobMD]

sender is basically a three-prong potentiometer which registers a specific amount of current to ground based upon where the float is in the tank. Your float may be rotted off. Pull the sender out and check for continuity. The resistance "winding" where it starts at the sender should not be grounding out to the sender body. Corroded senders often register "empty", while shorted to ground senders often register overfull.

Need to know the condition of the sender.