An occasional cough (engine miss) may be a "lean sneeze". This is not an ignition problem, but a lean condition inside the carbs. The idle passages may be restricted slightly,causing a lean condition every few rpm's. This can be from dried fuel gelatin inside those small idle passages inside the carbs. Solution: clean the carbs with a carb cleaner such as the aerosol product: Gumout. The recirc system is a fuel/air plumbing system on the front of the intake manifold. It sucks excess fuel from the back of the reed boxes and recirculates it to another cyl for complete combustion. Helps with idling. All the hoses and the one-way valves need to be connected and functioning. The fuel primer solenoid has a red lever on the side. The red lever needs to be in the "run" position. That means the length of the red lever needs to be oriented parallel to the length of the solenoid itself. If it's in the "service position" the engine won't run properly.