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

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

This water pump impeller repair kit is designed for a range of Yamaha and Mercury/Mariner outboard engines. It provides the necessary components to service or rebuild your water pump, ensuring proper engine cooling and performance.

This kit is a direct replacement for multiple OEM and aftermarket part numbers, providing a reliable solution for various 2-stroke and 4-stroke models from 1984 to 2002. Please verify your specific engine model and part numbers in the tables below before ordering.

• Installation Type: Direct replacement manufactured to OEM specifications.
• Engine Compatibility: Fits select Yamaha 20-30 HP and Mercury/Mariner 20-30 HP outboard models.
• Core Components: Includes impeller, key, gaskets, and seals for a standard rebuild. Complete kits also include the housing, insert, and outer plate.

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.

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

Yamaha Models

Mercury/Mariner Models

Technical Specifications

Package Contents

Note: Package contents vary based on the specific kit model selected. Not all components listed below are included in every kit.

• 1 x Impeller (662-44352-01-00 or 689-44352-02-00)
• 1 x Impeller Key (664-44338-00)
• 1 x Upper Water Tube Seal (664-44365-01)
• The following components are only included if purchasing a complete housing kit:
  • 1 x Pump Housing (689-44311-03)
  • 1 x Cartridge Insert (689-W4432-01)
  • 1 x Outer Plate (682-44323-00-00)
• Multiple Gaskets, Seals, and Bolts (actual quantities vary by kit model).

Installation Guide

Professional installation is recommended. The general steps below are for reference only.

1. Safety First: Disconnect the battery and disable the ignition system to prevent accidental starting.
2. Access the Lower Unit: Shift the outboard into neutral. Remove the bolts securing the lower unit (gearcase) to the engine's upper section.
3. Remove the Lower Unit: Carefully lower the gearcase away from the engine. You may need to disconnect the speedometer tube or shift linkage.
4. Expose the Water Pump: The water pump housing is typically located on top of the gearcase, surrounding the driveshaft.
5. Disassemble Pump: Remove the bolts securing the water pump housing cover. Slide the housing off the driveshaft to expose the impeller.
6. Inspect and Remove Old Parts: Take note of the orientation of the impeller vanes. Remove the old impeller, key, gaskets, and wear plate.
7. Clean Surfaces: Thoroughly clean all mounting surfaces, removing any old gasket material or corrosion.
8. Install New Components: Lightly grease the new wear plate and install it. Slide the new impeller key into the driveshaft keyway.
9. Install New Impeller: Lubricate the inside of the pump housing and the new impeller. Slide the impeller onto the driveshaft while turning the shaft clockwise to bend the vanes in the correct direction.
10. Reassemble Pump: Install new gaskets and re-secure the pump housing. Ensure all bolts are torqued to the manufacturer's specification.
11. Reattach Lower Unit: Guide the lower unit back into place, ensuring the driveshaft, water tube, and shift shaft align correctly. Secure with bolts.
12. Final Check: Reconnect the battery. Start the engine using a water supply (flushing muffs) and verify a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How can I confirm this kit will fit my specific engine?

A: The best way is to match your engine's model and year to our compatibility tables. We provide guides for both Yamaha and Mercury to help you locate your serial and model numbers. Cross-referencing your existing part number with our list is also a highly reliable method.

Q: What are the common symptoms of a worn or failed water pump impeller?

A: The most common sign is an overheating engine, especially at idle or low speeds. You may also notice a weak or nonexistent water stream from the "tell-tale" outlet port, which indicates poor water circulation.

Q: How often should I replace my water pump impeller?

A: As a general maintenance rule, it is recommended to replace the impeller every 1 to 2 years, or every 100-200 hours of operation. Frequent use in saltwater or sandy/silty water may require more frequent inspections and replacements.

Q: Is this an OEM part?

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.

Q: How fast do you ship and how much does it cost?

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.

Q: What is your warranty and return policy?

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.