Dan Bixter has posted an interesting condition he found on his
Ampico B.  To fully understand the situation, a few more details
should be known.  Absent those details, analysis can proceed by
doing just a few adjustments and observing the results.  Refer
to the drawing,

  http://www.mmdigest.com/Gallery/Tech/Ampico/amp11.htm

The Ampico B is a true balancing act in its regulation.  Any kinks
or obstruction in the wind lines running to both sides of the "C"
pouch will result in poor performance.

In theory, the adjustment of screw E should permit reducing the
vacuum to a near zero reading if the atmosphere entering the "C"
chamber is not restricted.  In making test adjustments, the first
intensity adjuster should be fully pulled out, the cancel valves
open (7B and 7T), and all intensity valves on the tracker bar closed.

If adjusting  the "E" screw in and out doesn't yield immediate and
direct variation to the stack pressure, a crisp or poorly seating
"C" pouch is suspected.

Before attempting to examine the "C" pouch, make sure that all
expression valves are working correctly.  Also, all holes except
one leading the to underside of the "C" pouch can be blocked and
the remaining hole used to check to see if the chamber is airtight.
Any leakage will screw up the regulation.

Since the curtain valve in the pump was found to be crisp,
I suspect the "C" pouches in the regulators are in the same condition.
Changing the curtain valve is an easy task and if it was omitted in
the rebuilding process, one assumes the same omission for the more
difficult task of changing the "C" pouch.

Let the list know your progress.

Bob Taylor