Never seen a fuel filter that came with a cap on it but all of the pumps I buy have caps that have to be removed before assembly because they have one way valves that can be damaged by dirt .
Your fuel solenoid has to open get as close as you can and turn on the key and listen for the click at the bottom of the carb sounds like that's your problem if it don't open you don't get gas in the bowl. Had another friend that had bad gas and it turned to like jelly and that wouldn't let it get gas to the carb but that doesn't sound like your problem sounds like the solenoid.