Pressure? 3 to 6 psi is all that's needed.
All it has to do is keep the bowl full - the carb bowl works just like a toilet tank ...
diymirage gave you a good way to test it. and as long as the bowl has fuel, it will even run for a minute or three.
There's a coarse sock filter in the fuel tank.
There's a finer can filter in line to the carb. Those will give you clues if there problems in the lines.
