You don't need to disconnect either line. As a matter of fact, I'd recommend leaving them both connected so that you get the tank completely empty. Put your throttle on idle or a click above, connect the glow ignitor, and start it.

OPTIONAL: Once it quits, if you want to store it, squirt whatever kind of oil you prefer directly into the carb opening, and then rotate the prop several times to distribute it a little bit.

David