Dear Clinton,  While reading of your problems with the air motor on
your player piano, it occurred to me that possibly the problem is not
the governor.  Rather, I wonder if something has come loose in the
linkage system between the Tempo control lever and the Tempo control
slide valve (which is typically integrated into the governor assembly).

Remove the kick board from your piano.  Move the Tempo adjustment
lever on the keyslip.  Identify the links which move when you move that
lever.  These links will have one branch which ends at a threaded rod
that slides in and out of a black box in the bottom action near the
motor governor.  That threaded rod moves the sliding valve that increases
and decreases the size of the vacuum port going up to the motor, which
in turn changes the motor speed.

Typically there are leather nuts on the threaded rod which enables you
to adjust the zero Tempo position.  If one of those leather nuts has
let go, it might not be moving the slide far enough to allow enough
vacuum to reach the motor.  If that is the case, you need simply
replace the faulty leather nut.

Also, the Tempo linkages are typically attached to the Tempo adjustment
rod under the key slip with a "bell crank" link that fastens to the rod
with a set screw.  If that set screw has loosened up, the same problem
could arise.

When things are working correctly, the slightest motion of the Tempo
lever should be reflected in a corresponding slight motion of the
threaded rod into or out of the governor assembly.

I hope this helps.  Enjoy your new player piano!

Best Regards,
Tom Chase
Minneapolis, Minnesota