OK, I though you had an electric pump
Being an rpm driven mechanical system, you'll find the pressure will go up as the revs increase, which will in turn decrease as fuel consumption goes up.
Rev the engine a little 2000 & 3000rpm and watch the gauge. It will hardly use any fuel (not being under load) and you should see the pressure go up. Did your mate change the idle rpm in the tune up/carby change?
Just as a comparison, my last stock mechanical pump (new) showed 8-9psi at idle at about 800-1000rpm.