Johnson Pump 09-810B-1 F4 Impeller (MC97)

The Johnson Pump 09-810B-1 F4 Impeller (MC97) is an essential replacement component for marine and automotive cooling systems that demand reliable water circulation under demanding conditions. As an engine cooling impeller, this part is critical to preventing overheating and maintaining optimal operating temperatures during extended use or heavy-load operation. Whether you're maintaining an inboard marine engine, servicing a high-performance water-cooled vehicle, or managing fleet maintenance schedules, this genuine Johnson Pump impeller is engineered to restore cooling system efficiency to factory specifications.

The F4 impeller design uses precision-molded elastomer blades that drive coolant throughout the engine block, cylinder head, and radiator circuit with minimal turbulence and maximum displacement efficiency. Unlike rigid metal impellers, Johnson's elastomer construction absorbs minor misalignment and reduces cavitation—a common failure mode when impellers wear or lose priming. The MC97 specification indicates compatibility with Johnson's mid-range marine pump housings, and the compact 4 x 1 x 7 inch footprint makes installation straightforward in tight engine compartments. Weighing just 0.25 lbs, this impeller resists corrosion from freshwater, saltwater, and coolant additives, extending service intervals compared to inferior aftermarket alternatives. Routine replacement every 12 months—as recommended by marine and automotive cooling system best practices—prevents catastrophic engine damage from coolant starvation.

This Johnson Pump impeller is ideal for boat owners, mechanics, fleet operators, and enthusiasts who prioritize preventive maintenance over reactive repairs. It fits Johnson Pump models equipped with F4-series housings and MC97 mounting configurations. Installation requires basic mechanical skill—typically a 15-minute job involving pump disassembly, impeller removal, and reinstallation with a fresh housing gasket. Using genuine OEM-equivalent parts like this unit ensures your cooling system maintains the performance and reliability built into your engine's design, avoiding the complications and expense of overheating-related damage.