1994 208 Fuel Gauge/Question

[Cajun Blues]

My fuel gauge is reading full all the time. I grounded out the positive wire from the gauge and the gauge works. The sender is a new style to me. Without taking it out it doesn't look like the old Tempo manual arm style to me. In a friend's 1984 208 you have to turn on a toggle switch to read the Fuel gauge. I don't see one on my boat. Is there a way to test this sender?
Thanks in advance for your response.

 

[seasick]

My fuel gauge is reading full all the time. I grounded out the positive wire from the gauge and the gauge works. The sender is a new style to me. Without taking it out it doesn't look like the old Tempo manual arm style to me. In a friend's 1984 208 you have to turn on a toggle switch to read the Fuel gauge. I don't see one on my boat. Is there a way to test this sender?
Thanks in advance for your response.

I don't fully understand what you mean by grounding out the positive wire. That is a short . I suspect you grounded the wire to the sender.

If your gauge is analog, it will have two or three wires ( 3 if it has a light). The terminal that goes to the tank sender when shorted to ground will cause the gauge to read full. If you disconnect the wire the gauge should read empty. Let's assume that worked. Reconnect the wires to the gauge and now disconnect the sender wire at the tank side. The gauge should read empty. If it doesn't the wire is shorted to ground somewhere.
If it does but the gauge still doesn't work correctly, the sender is probably bad. You can remove it to test but if your tank is near full, removing the sender flange may cause fuel to leak.

If you get the sender out, it will be either a float type ( with arm) or a stick type with a small float around the tube.
Connect an ohmmeter to the terminals of the sender ( signal and ground) and see what you get. Full ( arm or float up) should read about 30 ohms. Float or arm down should read about 230 ohms.
95% of the time, gauge problems are bad sender units.