Solenoid question 0n '83 911sc

[bbt]

Quick question for anyone familiar with solenoids and/or starting woes. When I removed the nut at terminal 30, the post is loose. It seemed to be have enough hold to allow me to remove the nut, but is this looseness normal? I like to avoid purchasing a new starter assembly if it's not needed. The car will not start as the starter is not engaging. I know the battery is good, and I installed a new neg battery cable, a new trans ground strap, and electrical portion of the ignition. A new hot relay kit from our host made no improvement. Can I,should I, test voltage at terminal 50 by pulling the wire off the tab and sticking a multimeter probe in it while an assistant turns the key? Any feedback would be greatly appreciated.