Water Pump Impeller Kit – Fits Yamaha F50A 4-Stroke (Replaces 6BG-W0078-01-00)

Water Pump Impeller Kit – Fits Yamaha F50A 4-Stroke (Replaces 6BG-W0078-01-00)

This water pump impeller repair kit is designed for Yamaha 4-stroke outboard engines, including the F40, F50A (1991–2007), F30LA, and F40LA models. It provides a reliable solution for maintaining your engine’s cooling system.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility for the specified engine models.

• Installation Location: Mounts in the lower unit gear case.
• Core Components: The kit includes the impeller, impeller key, and necessary gaskets for a complete service.
• Primary Fitment: Engineered specifically for Yamaha 4-Stroke 40–50 HP outboards.

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.

Technical Specifications

Package Contents

• 1 x Water Pump Repair Kit (6BG-W0078-01-00)
• 1 x Impeller (6H4-44352-02)
• Gaskets and O-rings
• Impeller Key

Installation Guide

1. Disconnect the battery and ensure the outboard is in neutral gear.
2. Place a drain pan under the lower unit and remove the gear case drain and vent screws to empty the oil.
3. Unbolt and carefully slide the lower unit (gear case) off the driveshaft housing.
4. Locate and remove the bolts securing the water pump housing cover.
5. Lift the housing off and remove the old impeller, gaskets, and wear plate, noting their orientation.
6. Thoroughly clean all mating surfaces of any old gasket material or corrosion.
7. Install the new wear plate, gaskets, and impeller key onto the driveshaft.
8. Slide the new impeller into the housing while turning the driveshaft clockwise to correctly seat the vanes.
9. Reassemble the water pump housing and tighten the bolts to the manufacturer-specified torque.
10. Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are properly aligned.
11. Refill the lower unit with the correct gear lube.
12. Start the engine using a water supply (flushing muffs) and confirm a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

How can I be sure this kit fits my Yamaha engine?
This kit is designed for Yamaha 4-stroke models F40, F50A (1991-2007), and F30LA/F40LA. It directly replaces OEM part number 6BG-W0078-01-00. Please verify your engine model and year against the compatibility chart. For additional help, use the Yamaha Serial Number Guide linked above.

What are the signs of a failing water pump impeller?
Common signs include a weak or nonexistent water stream from the engine's "tell-tale" indicator outlet, engine overheating alarms, or a noticeable drop in cooling performance, especially at idle.

How often should I replace the water pump impeller?
For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation. Replacement frequency depends on usage conditions, such as operation in saltwater or sandy/silty water.

OEM vs. Aftermarket?
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.

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

What is your warranty and return policy?
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.