Water Pump Impeller Kit – Fits Yamaha 2-Stroke 25HP & 30HP (Replaces 689-W0078-A6-00)

Water Pump Impeller Kit – Fits Yamaha 2-Stroke 25HP & 30HP (Replaces 689-W0078-A6-00)

This complete water pump repair kit is engineered for Yamaha 2-stroke 25HP and 30HP outboard models (including CV25, C25, C30, and CV30) and also fits a range of Mercury/Mariner 20HP, 25HP, 28HP, and 30HP outboards. It provides all necessary components to restore your engine's cooling system performance.

This assembly is a direct replacement for Yamaha OEM part numbers 689-W0078-A6-00, 689-W0078-06-00, 689-W0078-05-00, and 689-W0078-04-00. It also cross-references with Mercury/Mariner part numbers 47-42431M, 47-84829M, 47-97793M, 47-97793T, 47-81242M, and 47-95661M.

• Complete Service Kit: Includes a new impeller, housing, gaskets, plates, and hardware for a full rebuild.
• Direct Replacement Fit: Designed to meet or exceed OEM specifications for reliable installation and performance.
• Restores Cooling Performance: Replaces worn or damaged components to prevent overheating and maintain engine health.

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.

Technical Specifications

Package Contents

This kit includes the following components:

• 1 x Water Seal Damper (626-44365-01-00)
• 1 x Woodruff Key (664-44338-00-00)
• 1 x Water Pump Housing (689-44311-03-00)
• 1 x Water Pump Gasket (689-44316-A0-00)
• 1 x Cartridge Outer Plate (689-44323-03-00)
• 1 x Cartridge Gasket (689-44324-A0-00)
• 1 x Impeller (689-44352-02-00)
• 1 x Cartridge Insert (689-W4432-02-00)
• 3 x Bolts, With Washers (90119-06M07-00)

Installation Guide

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

1. Prepare the Engine: Disconnect the battery and shift the outboard into neutral.
2. Remove the Lower Unit: Unbolt and carefully slide the lower unit (gearcase) off the driveshaft housing. You may need to disconnect a speedometer tube if present.
3. Access the Water Pump: The water pump housing is located on top of the lower unit. Remove the bolts securing the housing.
4. Disassemble Old Pump: Remove the old housing, impeller, wear plate, gaskets, and seals. Note their orientation for correct reassembly.
5. Clean Surfaces: Thoroughly clean all mounting surfaces, removing any old gasket material or corrosion.
6. Install New Components: Assemble the new kit components in the reverse order of disassembly. Lightly grease the new impeller and insert it while turning the driveshaft clockwise to bed the vanes correctly.
7. Reinstall Housing: Secure the new housing with its bolts, tightening them to the manufacturer's specified torque.
8. Reattach Lower Unit: Realign and slide the lower unit back into place, ensuring the driveshaft, shift shaft, and water tube connect properly. Reinstall bolts.
9. Test Operation: Reconnect the battery. With the engine in a test tank or using "earmuffs" on the water intakes, run the motor and check for a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my Yamaha or Mercury engine?

A: First, check the Compatible Engine Models table on this page. For Yamaha and Mercury owners, we provide links to official serial number guides and parts catalogs to help you verify your exact model and the required OEM part number. This kit directly replaces Yamaha part numbers starting with 689-W0078 and the various Mercury numbers listed in our cross-reference table.

Q: What are the signs of a failing water pump impeller?

A: Common signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the 'tell-tale' outlet, and a brittle or cracked impeller upon inspection. Reduced cooling performance can cause severe engine damage if not addressed.

Q: How often should a water pump impeller be replaced?

A: As a general maintenance rule, we recommend inspecting your water pump impeller annually and replacing it every 1-2 years, or every 100-200 hours of use. Replacement frequency depends on operating conditions (e.g., frequent use in saltwater or sandy/silty water requires more frequent changes).

Q: OEM vs. Aftermarket?

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.