Water Pump Impeller for Select Yamaha 6 HP and 8 HP 2-Stroke Outboards – Replaces Yamaha 6G1-44352-00-00, Sierra 18-3066 and Mercury 47-11590M

Product Details

This aftermarket water pump impeller is designed for selected Yamaha 6 HP and 8 HP 2-stroke outboard engines. It is listed as a replacement for Yamaha 6G1-44352-00-00 and corresponds to Sierra 18-3066 and Mercury Marine 47-11590M reference numbers.

The impeller is intended to restore water circulation through the outboard cooling system when the original impeller is worn, cracked, hardened, or missing blades. Confirm the engine model, year, and existing part number before ordering; model families can use different impellers across production years.

• Replacement water pump impeller for selected Yamaha 6 HP and 8 HP 2-stroke outboards.
• Six-blade design for water circulation through the cooling system.
• Neoprene/chloroprene rubber construction for marine service.
• Single impeller supplied; water pump housing, gasket, key, cup, wear plate, and other service components are not included unless specifically listed below.
• Installation requires water pump and lower-unit service procedures.

Part Number Cross-Reference

These references identify the impeller application. They are not the internal product identifier.

Engine Compatibility

Catalog records identify Yamaha 6G1-44352-00-00 as an impeller used in selected Yamaha 6 HP and 8 HP 2-stroke outboard applications. The examples below keep horsepower, model, stroke, and year together. They are representative cataloged applications rather than a substitute for checking the exact engine model and service parts diagram.

Important: Mercury/Mariner reference number 47-11590M is associated with Sierra 18-3066, but a specific Mercury or Mariner model, year, and serial-number range should be confirmed from the engine's own parts catalog before purchase.

Technical Specifications

Product Type

Water pump impeller

Material

Neoprene rubber / chloroprene rubber (CR)

Blade Count

6 blades

Installation

Direct replacement; requires water pump housing and lower-unit disassembly

Approximate Dimensions

Height: 17.85–18.0 mm (0.70–0.71 in)
Overall diameter: 39.56–40.0 mm (1.56–1.57 in)
Hub shaft diameter: 11.80–11.9 mm (0.46–0.47 in)

Approximate Weight

10 g (0.35 oz)

What's in the Box

• 1 x water pump impeller

No gasket, impeller key, water pump cup, wear plate, housing, bolts, or complete water pump kit components are included with this single-impeller listing.

Installation Notes

1. Review the outboard service manual and disconnect the battery before beginning work.
2. Shift the gearcase as required by the service procedure, then remove the lower unit from the midsection.
3. Remove the water pump housing and note the position and condition of the old impeller, key, gasket, cup, and wear plate.
4. Remove the old impeller and clean debris from the pump housing and surrounding passages.
5. Inspect the housing, cup, wear plate, key, and shaft for wear or damage. Replace worn service parts before reassembly.
6. Install the impeller on the driveshaft with the key correctly positioned. Turn the shaft in the specified direction while seating the blades in the housing.
7. Reassemble the water pump and lower unit according to the service manual, using the specified torque values and sealants.
8. After installation, run the engine in a safe water supply and confirm proper cooling-water flow and operating temperature.

Troubleshooting & FAQ

Safety & Important Information

• Verify the engine model, year, stroke, serial range, and OEM reference before purchase.
• Compare the replacement impeller with the original part, including diameter, hub, height, and blade configuration.
• Do not operate an outboard that is overheating or has inadequate cooling-water flow.
• Professional installation is recommended if you are not familiar with lower-unit and water-pump service.
• This is an aftermarket replacement component and is not manufactured or supplied by Yamaha or Mercury Marine.

About Sea Sierra

• Marine Replacement Parts — Practical aftermarket components for routine outboard maintenance and repair.
• Application-Focused Listings — Reference numbers and model information are provided to help customers verify fitment before ordering.
• Service-Ready Support — Contact support with your engine model and existing part number if you need help checking application details.