108 starting/electrical problem
 

I need some help with an electrical issue. Just brought home a compete 108. Battery is good and charged, almost new. When you turn the key the solenoid clicks one time and nothing else happens. On one occasion the S/G moved maybe 1/16" and stopped. I'm not much on electrical problems and usually resort to being a "parts changer" instead of a mechanic. Any ideas on this would be welcome. I do have a good running 128 that I can use as a parts changer if needed.

The FIRST thing I would do, is examine the Battery Cables (Both Red and Black) on both ends, to make sure the connection points are....clean...bright...and tight.

Check all the connections of both battery cables for cleanliness and to be tight. After doing this, if the motor still won't crank, slip the belt off of the S/G and see if the S/G will motor freely when the key is turned. It's possible that the S/G is weak and needs repair, but verify that the connections are good first including the negative battery cable to ground.

Edit - Roland types faster than I do!

I would buy a cheap meter and make sure you are getting 12 volts at the s/g when you are turning the key and follow the volt back thru the starting circuit.

Solid advice. I would definitely check the cleanliness of connections, and how secure the connectors are. On 40 year old wiring, corrosion is probably the biggest problem. You can also try just jumping the battery (with a jumper cable) straight to the starter/generator and see if it chooches better.