A starter operates at the virtual equivalent of a dead short. You're reading a resistance through the windings of the field coils and armature that is so low your ohmmeter is seeing zero resistance.
Let's do a little math. A 6 volt starter that's drawing 200 amps will drop the terminal voltage of the battery down to about 4.75 volts or so due to the high current load. 4.75 divided by 200 (E= R X I ) gives a resistance of 0.02375 Ohms. Your ohmmeter simply can't read that low, even a digital one. The small stud is connected to the UPSTREAM side of the starter motor, not to ground. It is there to switch full battery voltage to the (+) terminal of the coil when a 12 volt ignition system is being cranked. As soon as the starter pedal is disengaged, the ignition primary voltage goes back to approximately 9 volts, from the downstream side of a ballast resistor that is there to protect the points from burning.
None of these items- - - neither -the bypass terminal nor the ballast resistor is used with 6 volts. A 6V starter switch does not have the small side terminal, since it is not needed. The switch with the bypass terminal will fit either starter, however.
NOW- - - - -please find out if you've got a 12V starter before doing ANYTHING else with the wiring system!
Jerry
