In looking at my TN-25 / 25 parts manual, it looks like the parts
that came out of my TN-28’s (less the missing spring) might
be carbon seal assembly parts from a TN-25 or 26 motor.
The diagram appears to show the “spring”, a “washer” atop of it,
and the “carbon seal with o-ring” above the washer.
The Johnson TN-27 / 28 Service bulletin parts and assembly
look a lot different.
My drive shaft appears to be the TN-28 style with the pressed on
collar below the spring.
Now What?
Prepare to be boarded!