The enricheners are what you have circled. When the motor is cold, these act as chokes. Also, the vents on the carbs are holes that you will not be able to see while mounted on the intake manifold, but will leak some fuel when the engine is tilted. You can also get fuel that will leak out of the carb throat, and move into the silencer. The silencer will also have some crankcase residue from the breather, which is vaporized oil and gas as the engine warms up and the breather recycles the vapors into the engine. This will make any fluids that exit the breather be a gas/oil/water vapor mixture -- dirty looking, gas smelling residue. All natural and mostly non-issues, unless it becomes extreme. You can reach the bottom carb drain fairly easily with a small box-end wrench. It only needs to be cracked open slightly to drain the carb. Do not worry about what you have seen -- you are just being extremely aware of something most others would not even notice. :smile Ron