Fuel gauge question.

[DT Fan]

It's in my boat, hence posting here. When you turn on the key, it goes to F. I have power to the gauge. When I check the sending unit, it too has power and the resistance does change as you move the arm. Can't tell you the numbers but if it's important I'll get them. 

I have to order a control cable for the livewell and if you're getting parts, might as well fire the cannon. Trying to get this thing in shape so I can get more serious about my fishing this summer.

[New Englander]

Might be a shorted wire. Lift the sending unit wire off the terminal and see if the gauge goes to empty.

EDIT: I mean off the gauge, not the sender. a common theme is low resistance is full, high resistance is empty thus an open circuit should read empty. 

Edited May 18 by New Englander
More info

[DT Fan]

Okay, when you remove the ground it does read empty. So which is bad, gauge or sender?

[CIHTECH]

Gauge likely works between an ohm range of 33 full and 240 empty. Remove sender wire from sender and with key on, short sender wire to ground. Gauge should read full. Next put ohm meter on sender terminal and chassis ground, sender should read somewhere between 33 and 240 ohm's. If reading falls between these thresholds look at tank level and compare ohm reading with tank level......take a swag and match to your reading / level for accuracy. 

If gauge doesn't respond to grounding sender wire, make sure gauge has (a) 12v on IGN terminal and (b) chassis ground on ground terminal, ground can be the gauge mounting bracket if only 2 studs on gauge. If only 2 studs the 2nd one will be the sender terminal. Jump a known ground to gauge if in doubt.