also i took off the cap and blew into the line. sure enough, the fuel blew right past the fuel pump and back down the line. it wasn't even super hard to blow either.
Wow that IS bad. I meant for you to blow back into the line leading INTO the pump but you went further.
Your fuel tank sock could be off of the fuel pickup and you may still be drwaing crud in from the tank so keep that in mind. Look carefully into the pump and lines when you take it off.
No, don't put check valves in the lines. Just another part(s) to fail or cause problems. Let the fule pump valves do it. They are normally very reliable.
I just was helping a guy who had a bad Airtex fuel pump and so maybe they have a batch of bad pumps out there. His outlet valve was bad, as evidenced by an immediate drop in fuel pressure to the carb when he shut the engine off. (But he also found a a batch of crud in the pump so it might have been self inflcited.) Perhaps take it back to NAPA, let them know your problem, get your money back, and get one eleswhere that is not an Airtex. NAPA stuff is normally OK, but they don't make the pumps...... I just don't know what is better or worse. Maybe others can share info on that.