Ok I’m doing this from memory but you can figure it out . First - the lines have nothing to do with impulse, so don’t worry about that. The three line coming out of the fuel tank are:
First - the front most line is the tank vent. It should fit over a white nipple at the fuel tank. The white nipple is the check valve, press fit into the tank, that allows vent air in to the tank. The other end of the vent line should just connect somewhere around the carb intake. Most Huskies don’t have this line, the fuel tank just vents right through the check valve.
Second - fuel io the carb. Middle, I think. Function is self explanatory.
Third line - is the return line from the purge bulb. When you use the purge bulb it SUCKS gas from the tank THROUGH the carb and then excess goes back to the tank through this line. This is probably the line that is plugged with the sheet metal screw.
What happens is over time the purge valve and/or it’s connecting lines age and develop leaks so people disconnect and plug them. The only line that is critical to saw running is obviously the line from the tank to the carb.
If you decide to replace the purge valve and reconnect everything as original just pay attention to how the purge valve is connected. The purge valve has an internal check valve and the lines from the carb and tank must be installed correctly.
If this doesn't get you going let me know. Like I said, I’m telling you this from memory but I have have a 353 and also some Jred 2152s to look at.
I'll see if I can get pictures tomorrow for you.
