On Sun, 28 Nov 2004 20:18:52 -0500, Bob Engelhardt
wrote:

Jim Levie wrote:
The unloader doesn't stay open after cutoff. It opens to relieve head
pressure and then closes. ...

Mine doesn't. Mine is opened by the armature of the pressure switch.
As long as the pressure switch is open, the unloader is open.

Just as a side note, many commercial pumps, such as IR on some models,
use a rather ingenious "governor" using weights at the end of the
crank shaft to depress a spring loaded valve at the end of the crank
cover, for an unloader.

I recently rebuilt one for a customer where the weight had come loose
and was laying in the bottom of the sump. A new pivot was ground from
drill rod and installed.

Gunner



Come shed a tear for Michael Moore-
Though he smirked and lied like a two-bit whore
George Bush has just won another four.
Poor, sad little Michael Moore

Diogenes