There should be a single wire that runs from the voltage regulator to the ignition switch. There are usually two more wires on this regulator that run under flywheel to the alternator coil. Use this Wie as the input or + on guage. Then make a wire to connect the other guage terminal to the Ign. Switch.
Did you also empty the fuel from the carb bowl. It may have some water in it which came in from the gas tank. Be careful not to break round gasket. Good Luck Friend.
