Sherwood Pump Impellers

Sherwood Pump Impellers: OEM-Quality Marine Engine Cooling

When it comes to keeping a marine engine cool, few components are more critical — or more in need of regular attention — than the raw water pump impeller. Sherwood Pump has been engineering seawater cooling solutions since the early 1920s, and their impellers represent some of the most trusted replacement components available for inboard marine engines. Today, as part of Pentair, the Sherwood brand has built on its history of quality designs and manufacturing to become the seawater pump of choice for many of the most prestigious engine manufacturers around the world.

What Sets Sherwood Impellers Apart

Sherwood impeller kits are original engine-specified, include all gaskets, O-rings, and service instructions, and feature a patented insert/puller system for easy removal — all designed to maximize performance and service life. This means when you install a Sherwood impeller, you're putting back exactly what the engine manufacturer specified, not a generic substitute.

Impeller materials are neoprene , which offers excellent flexibility and resilience in the demanding raw-water environment. Sherwood impellers are engineered for durability and reliability in the challenging marine environment, optimal performance across various boat types, and an extensive product range to suit different engine specifications.

Impeller Kits and Product Lines

Sherwood organizes its impeller lineup by pump series, making it straightforward to find the right fit. Key series include the G Series (10615, 9959, and 15000 impellers), the 18000 Pump Series, the 26000 Pump Series, the 27000 Pump Series, and the 29000 Pump Series — covering a broad spectrum of inboard engine applications. Part numbers ending in “K” designate impeller kits, which include the impeller, gasket, and O-ring , so everything needed for a complete service interval arrives in a single package.

Sherwood impellers are compatible with a wide range of engine brands, including Cummins, MerCruiser, and Johnson , making them a go-to source whether you're servicing a classic inboard or a modern diesel. Beyond impellers, a full range of Sherwood pump spares is available, including pulleys, service/repair kits, shafts, seals, gaskets, O-rings, cam plates, wear plates, and end covers — so a complete cooling system overhaul is always within reach.

Why Regular Impeller Replacement Matters

The seawater pump is the heart of the marine engine, supplying continuous water flow to maintain consistent engine temperatures — and the number one reason for premature engine wear is overheating. Neoprene impeller blades flex millions of times per hour under load, and they can crack or lose flexibility over time, especially if the pump is run dry even briefly. Replacing the impeller annually, or per the engine manufacturer's schedule, is one of the most cost-effective maintenance steps any boater can take. To maintain engine performance, warranty, and reliability, insist upon the original, engine-tested and engine-specified Sherwood pumps.

Whether you're prepping for the start of boating season or making an emergency repair dockside, browse the full selection of Sherwood Pump impellers to find the exact kit your engine requires.