I would vote for the Carb. if it runs when you prime it, I would think you have spark and just running out of gas after priming. So first thing would be to check for spark and eliminate an electrical issue. You might have to check with priming and running and then again just after it quits. The condenser may just work for a while and quit. What does the screen in the fuel pump look like? Is it clean? Hard to believe with all the new stuff that you have replaced that there would be junk in the new lines. What kind of carb, Carter or rochester? You can get a screw in filter for them or an old school glass bowl one and put it just ahead of the carb. Is there any evidence of flooding around the base of the carb? These are most of the things I dealt with recently caused by a dirty and now replaced tank.
