Sierra Impeller 18-3068 for Yamaha Outboard Engines, Replaces 6H4-44352-00-00

The Sierra Impeller, part number 18-3068, is a water pump impeller engineered for Yamaha outboard engines. It is designed as a direct equivalent to the Yamaha 6H4-44352-00-00 impeller, restoring proper raw-water circulation through the engine's cooling system. The water pump impeller is a critical wear item: as it spins inside the pump housing, its flexible vanes draw in raw water and push it through the cooling passages to keep the engine running at a safe operating temperature. Over time and use, impeller vanes lose their flexibility and set, crack, or shear, which reduces water flow and can lead to overheating if not replaced. Sierra Impeller 18-3068 is built to meet or exceed the specifications of the original equipment part it replaces, making it a straightforward drop-in replacement for routine water pump maintenance or a full water pump rebuild. It ships as a single impeller (package quantity of 1), so buyers doing a complete pump service should also plan for the corresponding pump case gasket, impeller plate, and impeller key as separate items if their rebuild calls for them.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3068
• Product Type: Engine Water Pump Impeller
• Weight: 0.04 pounds
• Package Quantity: 1
• UPC: 030999315205

Fitment

• Yamaha outboard engines

Replaces (OEM)

• 6H4-44352-00-00

Frequently Asked Questions

What does the Sierra 18-3068 impeller fit? Sierra Impeller 18-3068 is built for Yamaha outboard engines as a replacement for the Yamaha water pump impeller.

What OEM part number does 18-3068 replace? It replaces Yamaha OEM part number 6H4-44352-00-00.

How many impellers come in the package? One impeller ships per package; the package quantity for Sierra 18-3068 is 1.

Is the Sierra 18-3068 impeller genuine Yamaha or aftermarket? It is an aftermarket Sierra part manufactured to meet or exceed the specifications of the original Yamaha 6H4-44352-00-00 equipment part it replaces.

How much does the impeller weigh? The Sierra 18-3068 impeller weighs 0.04 pounds.

Do I need any other parts to complete a water pump rebuild with this impeller? The 18-3068 listing covers only the impeller itself; a full water pump service on the same engine may also call for a pump case gasket, impeller plate, and impeller key, which are separate part numbers.

How do I know if my impeller needs replacing? Signs of a worn impeller include reduced or no water flow from the engine's cooling stream, overheating, and cracked or missing vanes when the old impeller is inspected; Sierra 18-3068 is the replacement part for Yamaha engines showing these symptoms.

What is the UPC for this part? The Sierra 18-3068 impeller has UPC 030999315205.

Can I use 18-3068 as a routine maintenance item? Yes, Sierra Impeller 18-3068 is intended for routine replacement of the Yamaha outboard water pump impeller as part of standard cooling system maintenance.

What is the part number I should search for to find this impeller? Search Sierra part number 18-3068, which cross-references to Yamaha 6H4-44352-00-00.