<h2>Water Pump Impeller for Mercury</h2><p>This marine water pump impeller replaces Mercury outboard boat motor part numbers 47-803748 and 18-8921, ensuring proper coolant flow for your engine.</p><h4>Overview</h4><p>The water pump impeller is a critical component for Mercury outboard motors, circulating coolant to prevent overheating. This replacement impeller is designed to match original specifications, offering a direct fit for your marine engine. Keep your boat motor running smoothly with this durable water pump impeller.</p><h4>Built For Performance</h4><ul> <li>Precision-molded rubber blades for efficient water flow</li> <li>Stainless steel insert for hub strength</li> <li>Handles high RPM without deformation</li> <li>Exact OEM dimensions for direct replacement</li> <li>Resists heat and wear for extended service life</li> </ul><h4>Specs At A Glance</h4><table><tr> <td><strong>Part Number(s)</strong></td> <td>47-803748, 18-8921</td> </tr></table><h4>Good To Know</h4><p><strong>Q:</strong> How often should I replace the water pump impeller? <strong>A:</strong> Typically every season or after 100 hours of use, as rubber blades wear and lose pumping efficiency.</p><p><strong>Q:</strong> Will this impeller fit my Mercury outboard? <strong>A:</strong> This impeller corresponds to part numbers 47-803748 and 18-8921, so verify your engine's part number for compatibility.</p><p><em>Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.</em></p>