Hi all,
I pulled out the starter and did the bench test. I went right out to the end effortlessly. It is a 6 volt starter. The replacement solenoid was put on just before I bought the car. It is the square one. I had a rebuilder put in the used bendix for me since I could not figure out how to slide the armature/bendix unit out past that fork of the engaging lever. There is a large piece right behind the drive gear that doesn't have enough clearance to slide out. I don't know the secret there(but would like to).
Anyway, I think my problem is that the gear doesn't retract enough so it's pushed right up against the flywheel teeth. I can slide the gear back into the starter body more but it springs back out again about a half centimeter.