I am working on a 1923 Marshall & Wendell Ampico which was "rebuilt"
some years ago.  After restoring it, the wind-motor will not govern
properly.

After eliminating all other possibilities (chain tension, brake
tension, binding shafts, wind-motor problems, etc.) I believe that the
governor pneumatic dimension used by the last rebuilder, and which I
transferred to the new cloth, may be incorrect.

Does anyone have the correct opening for the governor on this model of
instrument?  (This is the earlier model, without the regulating pouch
on its movable board.)  Or, if another model of piano, please include
the physical dimensions of the governor so that I can compare them, for
identification purposes.

Many thanks,
Larry Broadmoore