Saw Steve Dean's post in 190330 MMDigest about a Wurlitzer 105 problem.
We have a 105 which had, and still has, a similar problem which we have
not yet fully resolved.

I _hate_ Wurlitzer 4-in-1 valves.  Our problem seems to be that, even
if a valve tests okay on the bench, it may not pick up or close tightly
under low vacuum which you have when starting the pumps.

The 4-in-1 valves are apparently very touchy about internal clearance
when under no vacuum.  If the clearance is too great they have trouble
closing when starting the pump.  Since we have never fully and reliably
succeeded in this valve rebuild, I have no magic formula for you.  When
you have the answer we would be very interested in it.

Good luck!

Scotty Greene - DeBence Antique Music World
Franklin, Pennsylvania