I was going to take it apart and investigate, but the problem has gone away now that the weather has warmed up.  The starter has engaged perfectly every time for the last few weeks.

William Greenamyer <greenamyer@YAHOO.COM> wrote: Talked to you before about having the same problem.  Sure enough, when it
warmed up, the starter engaged the ring gear.  Thus I am guessing the
solenoid.  I have two rebuilt starters that do the same thing.  One was used
for two years before it started having the problem.

Did anyone come back to you on this with respect to disassembly of the
solenoid and what to use to lube it?

William