Most carbs have a vent tube from inside the bowl/float area. I have seen carbs spew streams of gas out that vent tube when the float got heavy, or the needle and seat got trash under it.

If the plugs are wet with gas, my bet is the floats are either too high, or there is a piece of trash that worked it's way up under the seat causing the bowl to overflow. It can't push it all through the small nooks and craniies, so it hunts the least path of resistance, right out the top. Then a lot will fall back into the throat of the carb.