Hi GVB,
Gas spilling out of your carburetor would not typically be caused by the wrong sized fuel line unless of course it is leaking at the hose connection itself. Gas spilling out of the carburetor is usually caused either by a carb bowl venting problem (clogged vent) or a needle and seat which is stuck or worn.
The fuel line on mine is 1/4″ inside diameter, some have used 3/16″ inside diameter. As long as it fits snug it will be fine.
