I went to start the car after removing the motor for 6 months and the starter did nothing.
I pulled it apart and can't understand how it works.
I put 12V direct to the main power buss and negative battery lead to the smaller plug and nothing.
If I move the 12V battery lead to the other side of the starter, to the main lead that goes to the motor, the Solenoid kicks out just fine.
If I move the negative lead to the starter body, the motor turns just fine.

The part I don't understand is that the main power lead goes to the "Solenoid switch contact" but nothing else. That's a dead end unless the solenoid is activated.
So what activates the solenoid?

I found this thread with lots of photos but no answer http://www.thesamba.com/vw/forum/viewtopic.php?t=384710

When mounted on your motor/trans both the motor and the solenoid receive negative ground from the battery. No other negative wires are attached.

Put the 12v positive directly to the Positive buss on the starter.
The other buss on the starter is for positive coming from the ignition key (though a relay).

If you have a cheap starter switch from the local flaps you can put it between the positive buss on the starter and the solenoid buss. With the starter body grounded, and the pos from battery hooked to the pos buss, Push the button and the starter will turn.

Make sure the car is in neutral when you are doing this stuff!
When you energize the solenoid it completes the circuit allowing pos electricity from the pos buss to flow to the motor.

main power lead goes to the main large power bolt on the solenoid.
Ground it the body of the starter.
Solenoid gets activated (triggered) by the yellow wire coming from the ignition switch.

To bench test, put ground on the body.
Put power on the large main power stud.
jumper power to the small trigger (typically a spade plug)

that will trigger the relay to run the main power through the solenoid and spin the starter.

Rich

Cool!
Starter works fine.
The problem is in the the yellow wire coming from the ignition switch.
I was thinking with a big + lead the smaller wire must be a - lead
I should be able to track the problem down now with out too much trouble.
Thanks guys.