I've had this problem plaguing me ever since I bought my van.  It just
doesn't like starting in the cold.  I have replaced batteries and coil.
The DPO had recently replaced the starter trying to resolve the same
problem.  When it is cold outside (noticed anywhere below 10C) I cannot
get it to start.  I spent 25 minutes one day, with a boost from my truck
trying to get it going without luck.  The next day, it warmed up, and
after sitting in the sun all day, I jumped in and it started on the
first crank without any boost.  When I do boost it, the engine still
struggles to turn-over as though the battery is just about dead.  That's
what always happens in the cold (whether boosted or otherwise).  When
it's warm, the engine turns over a lot faster although it frequently
still takes several attempts before she'll catch.

Any ideas?

\/\/i!!y
1980 Westfalia (Air Cooled)