At 10:57 AM 5/29/2012, Steve Williams wrote:
>What is this small hole in the face of my propane regulator?

It's the ambient-pressure vent for the main diaphragm.  Marshall
Brass quit making these regulators many years ago because the
rectangular diaphragm was subject to fatigue failures at the
corners.  Yours is long overdue to have failed.  Replace it with a
Marshall - 290 I believe is the correct one, for horizontal mount -
someone will confirm.  It's about an inch longer, you'll have to
massage the connecting lines a bit or shorten them.

Yours,
David