Re: Starter test
Ok, a little education here. The inside of your starter has two large permanent magnets on the shell. The armature has very heavy low resistance wire wound in several circuits. When connected through the solenoid, very high current (amps) flows through and makes a strong magnetic field that reacts against the permanent magnets, spinning the armature with great force and generating a lot of heat. That's why you don't run the starter continuously. The commutator (the copper segmented piece that the brushes ride on) reverses the current in sequence so that the magnetic field first pulls toward the magnet then as the armature approaches the magnet it pushes away. (Because both magnets have north and south poles).
If you have shorted some of the armature windings by melting, or burning insulation, the undamaged ones will still create a magnetic field so the damaged starter will still turn but not generate enough horsepower to crank the engine. If the commutator is dirty or segments are shorted together, again, the motor may spin but not develop adequate power.
The black wire from your solenoid is the ground for the solenoid. I have never seen one connected that high on the engine. the ones I have seen were connected to the lower shroud. The other fine wire (usually yellow but could be another color) on the solenoid is the neutral interlock wire. It comes from the microswitch on the shift linkage. When you turn the ignition to start, current is sent to one side of this switch. If the switch is depressed (engine in neutral) the current goes to the solenoid and activates it. This closes a high current contact which sends battery current through the solenoid to the starter motor.
I don't understand what you mean about hot wiring the starter. If you want to bypass the ignition switch, just jump from the battery side of the solenoid to the neutral interlock terminal on it. It is low current so it only sparks a little if you use a jumper wire.
