The color of the spring indicates at what RPM the clutch engages. There is a chart that tells the color and the rpm.
The driven clutch will not spin until the drive comes together and engages the belt.
There are also weights that go on each puck which allows you to tune the clutch. also the spring can be changed for tuning.
It took you years to get back to it you must have been pissed. There are a lot of good guys here that know a lot more about the fl350 and a 102c then me. I'm sure you can get ti going.
I assume your
Engine is running properly turning the clutch at the proper rpm.
If it had a purple in the auction then you received a yellow - that tells me the seller must have changed it. Perhaps he did not get it back together properly. The first thing I would try is compressing the clutch plates by hand to see if they are free to move. Also pictures are a plus.
I'm sure fl350 guys will chime in soon and correct me if i told you anything wrong. I'm a pilot owner but the drive system are almost the same as the fl350.