[Blue'72]

Welcome from Washington! The click indicates that the solenoid is getting power and the wine is the starter motor wanting to turn. It sounds like it's not getting enough power to the starter. The wires could be corroded, loose, weak, broken, or the battery could be weak. Check to see if the battery cables are sealed to the battery connector ends, or if they are stripped and have add on connectors "bolted" on. If there is any copper visible on the end of the wire, there's a good possibility that corrosion has set into the wire and causing too much resistance. I chased this same problem down years ago and ended up replacing battery, cables, starter, and solenoid. I think the problem was actually the smaller wire that came off the positive battery cable and didn't have a very good connection with the rest of the wiring. Check the ground on the negative cable and also look for good ground straps from the engine to the frame. It might be as simple as a bad ground. It's important to have at least one copper ground strap securely connected from the engine to the frame.

Good luck!