A potential bad gauge or sender unit in the tank would cause it to read full all the time.
You need to check the radiator and be sure it is full. It can be empty and the overflow tank full. If it is full then check and be sure the radiator cooling is working when the engine is at operating temperature.
You need a new fuel pump
A short in a wire or a failure of gauge or sender.
Faulty signal sender in the tank.
Radiator could be plugged or restricted
fuel sending unit
a bad sending unit in the gas tank.
Would not recommend using a full choke or even a 20 gauge, 12s are much better
The fuel gauge on a 1985 Chevy Silverado will read full all the time if the sending unit is defective or the wire has come loose. When the tank is full, the sending unit normally shuts off which cause the gauge to read full.
You bet! keep that baby full at all times
If only the temperature gauge does not work, then a fuse is not the problem. Be sure that the radiator is full. If not you will need to fill it as the temperature sender needs water around it in order to have something to sense. If it is full then take it to a repair shop and have them check it out.