Water Pump Impeller Kit – Fits Yamaha 20/25/30 HP Outboards & Mariner 20/25/30 HP (Replaces 689-W0078-A6/689-W0078-A4)

Water Pump Impeller Kit – Fits Yamaha 20/25/30 HP & Mariner 20/25/30 HP Outboards

This water pump impeller repair kit provides the necessary components for servicing the water pump on select Yamaha and Mariner 2-stroke outboards. It is designed to fit Yamaha 25-30 HP models from 1984–1997 (including C25, CV25, C30, CV30) and specific Mariner 20-30 HP models (20C, 25C, 30A) with corresponding serial numbers.

This kit is a direct replacement for Yamaha part numbers 689-W0078-A6-00, 689-W0078-A4-00, and 689-W0078-04-00, as well as several aftermarket equivalents from Sierra Marine, GLM Marine, and Mariner.

• Engineered for durability with high-quality materials to ensure reliable cooling performance.
• Features an impeller designed for higher flow rates to maintain optimal engine temperature.
• Provides a complete solution with an impeller, housing, wear plate, gaskets, and hardware for a full replacement.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Yamaha owners, here’s a guide to help you identify your engine’s serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Yamaha Outboard

Mariner Outboard

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (689-44352-02-00)
• 1 x Woodruff Key (664-44338-00-00)
• 1 x Pump Housing (689-44311-03-00)
• 1 x Insert Cartridge (689-W4432-01-00)
• 1 x Wear Plate (689-44323-02-00)
• 1 x Gasket (689-44324-A0-00)
• 1 x Gasket (689-44315-A0-00)
• 1 x Water Seal (626-44365-01-00)
• 3 x Bolt with washer (97080-06030-00)

Installation Guide

1. Disconnect the negative battery cable and remove the engine cover for safety.
2. Locate and unbolt the lower unit (gearcase) from the outboard's midsection.
3. Carefully lower and separate the gearcase to expose the driveshaft and water pump assembly.
4. Remove the bolts securing the water pump housing and slide the housing off the driveshaft.
5. Take note of the old impeller's orientation, then remove it along with the woodruff key.
6. Remove the old wear plate and gaskets, then thoroughly clean all mating surfaces.
7. Install the new lower gasket and wear plate.
8. Place the new woodruff key in its slot on the driveshaft and slide the new impeller on, rotating the driveshaft clockwise to seat the vanes.
9. Install the new insert cartridge and gasket into the pump housing.
10. Slide the new housing assembly over the impeller and secure it with the bolts, tightening to the manufacturer's specified torque.
11. Carefully guide the driveshaft back into the powerhead while reattaching the lower unit.
12. Reconnect the battery, start the engine in water, and confirm a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

A: This kit is designed for specific Yamaha 25-30 HP models (1984-1997) and Mariner 20-30 HP models requiring a 6A9 or 684 serial number prefix. Please carefully review the "Compatible Engine Models" table and cross-reference your engine's model, year, and serial number before purchasing to ensure a correct fit.

A: The most common signs of a failing impeller are engine overheating alarms, a weak or inconsistent water stream from the tell-tale outlet, or a complete lack of water flow. Upon inspection, a worn impeller may have brittle, cracked, or broken vanes.

A: As a crucial part of preventative maintenance, we recommend inspecting the impeller annually and replacing the entire water pump kit every 1-2 years or every 100-200 hours of operation. Replacement frequency may vary based on usage (saltwater vs. freshwater) and operating conditions.

A: Yes, this is a comprehensive repair kit. It includes the water pump housing, impeller, wear plate, insert cartridge, woodruff key, and all necessary gaskets, seals, and bolts as detailed in the "Package Contents" list.

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.