Sierra 18-3021 Neoprene Marine Raw Water Pump Impeller 8-Blade Key Drive

The Sierra 18-3021 is a neoprene flexible impeller designed for marine raw water pump applications. Built to meet or exceed OEM specifications, this direct replacement impeller fits Jabsco and Oberdorfer pump models and is engineered to deliver reliable cooling and water transfer performance in both freshwater and saltwater environments.

Key Specifications:

• Outer Diameter: 2-9/16 in. (65 mm)
• Width (Depth): 2 in. (51 mm)
• Shaft Diameter: 5/8 in. (16 mm)
• Number of Blades: 8
• Drive Type: Key drive
• Insert Material: Brass
• Impeller Material: Neoprene
• Jabsco Impeller Profile: M

OEM Cross-Reference Numbers:

• Jabsco: 4598-0001, 04598-0001, 4598-0001-P
• Oberdorfer: 6603
• UPC: 808282146214

Key Features:

• Neoprene construction suitable for fresh and saltwater pumping, including applications where minor amounts of oil or diesel fuel may be present
• 8-blade design promotes efficient, smooth water flow with reduced cavitation
• Brass insert provides a secure, durable fit on the pump shaft
• Key drive ensures positive engagement and reliable torque transfer
• Meets or exceeds original equipment manufacturer specifications
• Backed by Sierra's limited lifetime warranty

Replacing your raw water pump impeller on a regular basis — at minimum annually or as required by use — is one of the most important steps in maintaining your marine engine's cooling system. The Sierra 18-3021 makes routine service straightforward with a design that fits precisely into compatible Jabsco and Oberdorfer pump housings.