Poulan chain saw, 3-yr old, small 2 cycle engine, starts on full choke but dies after 2 or 3 seconds. I discovered a broken primer bulb, replaced that, and ensured I am using fresh fuel.. still have same problem. I removed air filter, squirted carb cleaner down carb throat.. engine started on first pull, and ran about 5 seconds. I then noticed what appears to be a small fuel line on a corner of the carb, but the other end is obviously broken and I cannot see where it might have been connected. I verified the fuel circuit from gas tank to primber bulb and from primer bulb to the carb (a port opposite side of carb from the above-mentioned port with broken line). The only place I see where the disconnected fuel line might go is a small hole on the fuel tank molding. I'm wondering if this might be a connection where the attached line creates a circuit (either pressure or vacuum), which helps fuel to flow to the carb? It just seems like the engine dies as soon as it looses it's prime. Any houghts? Am I on to the right path?