[Excaliber]

Now I'm confused!

Big terminal on the left is direct battery PLUS cable. It is generally THE connection that ALL other wires get their power from. Main power TO the "fuse block" for instance would come from a smaller wire attached to the BIG left terminal/postive battery cable connection. That way the "fuse block" ALWAYS has power direct from the battery.

The right side OTHER BIG terminal gets a large wire from it directly to the started terminal. When the solenoid (switch) closes it connects the left side (direct battery plus power) to the right side which feed direct PLUS battery power to the starter.

SO, how do you turn on the switch (solenoid)? By applying 12 volts PLUS power to one of the small terminals in the front. I do blieve as Ron has said it is the "S" terminal.

The OTHER small terminal RECEIVES 12 volt power ONLY WHEN AND DURING THE ACTUALL TIME THE SOLENOID IS "ON". In other words, only when the starter is actually cranking. Otherwise there is NO POWER at the second terminal at all. So WHAT would a guy use that terminal for?

It's kind "old school" and goes back to the days of "point type" ignition systems. When the starter is engaged it draws a tremendous amount of power from the battery. Typically dropping available voltage from 12 or 13 down to 10 or so.

IF it drops below 9.6 volts good chance your battery is bad. Anyway, the old point type systems (and SOME new electronic units) will BURN UP if you put 12 or more volts to them. So they get powered through a resistor, which drops battery voltage from 12-13 down to 7-8 volts (some say 6).

Now during CRANKING (starter spinning) and battery voltage dropping due to the big load, and the resistor ALSO dropping the now LOW voltage to the coil even lower there is no power left to FIRE the coil. The coil, during cranking may only be getting 4 or 5 volts, perhaps less. SO, the SECOND SOLENOID TERMINAL provides a temporary BY PASS around the coil resistor and puts ALL AVAILABLE voltage directly to the points/electronic ignition/coil (which would be about 10 volts). THUS providing a HOT spark during the cranking phase.

Think of it this way: BOTH the big and small terminals on the right receive battery power ONLY when the solenoid is actually engaged. The two terminals do different jobs, one for the starter (big guy) and one for the ignition/coil/points (little guy).

...class dismissed.

Ernie