On Thu, 19 Apr 2018 12:11:09 -0700
Bob La Londe wrote:

huge snip
As soon as the valve opened up it would
equalize pressure and flow fine until the compressor motor turned off.

Many years ago when I was a tween Dad brought home a small
single stage air compressor that needed a motor. We scrounged up 1/3 hp
and I put it together along with a new hose and fittings. The check
valve had problems so I just removed it. Without the check valve it
wouldn't pump up much and the motor would stall out. Something like
40-50 psi max. Of course it wouldn't hold pressure either, leaking back
through the pump when I pulled the plug... So I cleaned up the check
valve and put it back in. Then it would pump up to over 100 psi before
the motor stalled out. The point being is that the check valve was
cycling back and forth with each stroke of the pump. It didn't just
open and then close when the pump shut off.

I learned a lot about air compressors, quick disconnects... with that
little project. I think Dad planned it that way

--
Leon Fisk
Grand Rapids MI/Zone 5b