Mercury - Quicksilver Upper Water Pump Housing Reinforced Nylon Construction 803750A05. Overview. A strong, leak-free cooling system starts with quality components. The Mercury Marine 803750A05 Quicksilver Upper Water Pump Housing is built from reinforced nylon to handle heat, pressure, and long hours on the water without warping or cracking. Designed for Mercury and Mariner F8/9.9HP FourStroke BigFoot, F15/20HP FourStroke, and select 9.9HP-18HP TwoStroke outboards, this OEM housing ensures cons