When i installed the gauge with valve in place, i got zero.
Removed the valve, and installed gauge. Primed pump and got 38ish (couldnt see well when turning key on). And with key (pump) on after it primed, it would leak back down to zero in about 12seconds.
Started it up, and was running at about 37ish psi. I figure to compensate for the long rubber hose of the pressure tester, and the gauge itself, thats about right. ?