Can you run through that again?? I thought 1 is the main fuel line, line running from the tank to the carb and putting fuel in the bowl, 2 is a vent line, and idk what 3 is, that’s why I’m here, lol.Correct. 1 is vacuum to run the petcock. 3 is the fuel line from petcock. The vent tube hooks in to a couple of holes on the side of the intake runner, keeps it out of the way.