That happened to me with my '81 last summer. It would not start the van
then, after a short rest, would work. I tried milking it across Nevada. Spent
the night in a rest area after it wouldn't restart. Still wouldn't start in
the morning. Jumpered both sides right to the battery with no results. Pulled
it out and spun it on the ground and reinstalled it whereupon it started the
van. It finally died for good 30 miles from home after a 3000 miles trip. A
rebuilt one from NAPA has been holding up since then but all bets are off
next summer. They do get what seems to me unreasonably hot. Maybe the starter
is part of the engine cooling system.

Steve  '81 Country Home Vanagon