Mercury - Water Separating Fuel Filter High-Capacity Filtration Marine-Grade Construction 8M0154754. Overview. Every boater knows the feeling-slipping away from the dock, hearing the engine settle into a steady rhythm, and trusting that everything under the cowling is doing its job. Clean fuel plays a huge role in that peace of mind, especially on long runs where you can't afford hesitation or roughness. That's why having a reliable water separating filter isn't optional; it's essential. With th