Mercury - Under-Cowl Inline Fuel Filter Screen Fuel System Composite Mesh 8M0090809. Overview. Every boater knows that the smoothest days on the water start long before the engine even turns over. It begins with the quiet confidence of knowing every component feeding your motor is clean, protected, and doing its job without complaint. That is exactly the kind of trust the Mercury 8M0090809 Under-Cowl Inline Fuel Filter Screen gives you. You do not notice it when everything is running right, and