Reply to Old Magnet:
15 psi was the expected high end fuel gauge pressure.
Hi Team,
here are two scans, one of tests done at our Dealership back in the 1960's
The normal full fuel pressure was specified at around 30 psi.
15 psi is when the gauge reaches the centre of the green on the 3H3344 gauge or, Normal range on the early gauges.
The pressure will rise in the system but the gauge will act as outlined with 15 psi being the lower end of usage below which power loss will start to be noticed on the engines in question.
We found on later high horse power engines that power loss started to show at around 24 psi and below, in some applications it was more like 27-28 psi.
Cheers,
Eddie B.