Hi MMD'rs,  I was summoned to a customers home to inspect a 5'4"
Chickering Ampico "A" system, 1925-ish, with right-side-up valves.
The pump was rebuilt by another person and installed.

The complaint was the pump is making the piano shimmy.  The motor
has the correct pulley and flywheel and is smooth turning in the
correct range of RPM.  The pump has no knock and it loads up good when
required.  The belt was replaced as a solution but made no difference.
The plans now are to pull the pump after the MBSI SE Chapter meeting
in Plantation, Florida.

Am I looking for the connecting rods to be out of sequence?  I don't
know yet if they're metal or wedge rods.  Can a difference in pneumatic
distance cause a unbalance?  Please feel free to kick this one around.

Warren Officer
Jacksonville, Florida