Sierra 18-0421 Outer Wear Plate for Yamaha Outboard Water Pump

The Sierra 18-0421 Outer Wear Plate is a precision-manufactured replacement component for Yamaha outboard engine water pump cooling systems. This plate serves as the base surface against which the water pump impeller rotates, protecting the pump housing from direct wear and maintaining efficient coolant flow to the engine.

Sierra's replacement outer wear plate is engineered to meet or exceed OEM specifications, offering a reliable and cost-effective alternative to the Yamaha OEM part. It is a direct replacement for Yamaha OEM part number 6AW-44323-00 and is a key component found in the Yamaha 6AW-series water pump repair kit (Sierra 18-3477).

Key Features:

• Direct replacement for Yamaha OEM part number 6AW-44323-00
• Engineered to meet or exceed original equipment manufacturer specifications
• Built with marine-grade materials for reliable performance in demanding saltwater and freshwater environments
• Compatible with Yamaha F300, LF300, F350, LF350 V8 5.3L four-stroke outboard engines
• Sold individually; often used during water pump impeller service intervals

Replacing the outer wear plate at each water pump service interval helps ensure optimal pump efficiency and prevents premature impeller wear. This part is commonly serviced alongside the impeller, insert cup, and water pump gaskets.