With my '84 GL the starter worked great until we actually got the engine so it
would run.  Then we would have to hit the  starter with something to get it to
engage.  My father opened up the starter and cleaned out and lubed the
armature area.  Didn't help.  So today we opened up the solenoid area.  It was
just a little gunky inside but enough to make it stick and not engage.  We put
it back together and it would spin but not engage (shoot out).  Took it apart
again and the arm that pushes the gear out to engage the starter must be
pulled back with a piece of wire or something and then while you hold the gear
in the out position, you can pop in the part of the solenoid that is near the
arm (it attaches to it by the arm inserting into a rectangular hole in the
stud that is part of the solenoid).  Put it back together after cleaning and
WD-40.  Works great!  So this might be something to try for those sticky
starters.  Had to use a punch and hammer to break those regular head screws
loose in the solenoid.  Those things never come loose with just a screwdriver.
Hope this helps somebody.
Ken Wilford
John 3:16