Water Pump Impeller Repair Kit – Fits Yamaha 2 & 4-Stroke 50-115 HP (Replaces 6H3-W0078-02-00, 68V-W0078-00-00)

Water Pump Impeller Repair Kit – Fits Yamaha 2 & 4-Stroke 50-115 HP

This water pump impeller repair kit includes all necessary components to service the lower unit water pump on compatible Yamaha outboards. It is designed for select Yamaha 2-Stroke 50-70 HP (1992-2003) and 4-Stroke 75-115 HP (2002-2010) models.

This kit serves as a direct replacement for Yamaha OEM part numbers 6H3-W0078-02-00, 68V-W0078-00-00, and Sierra part numbers 18-3466, 18-3461, 18-3442, and 18-3523.

• Includes a complete water pump housing, impeller, wear plate, gaskets, and hardware.
• Engineered for both 2-stroke and 4-stroke engine applications as specified.
• Installs in the lower unit/gearcase to restore cooling system performance.

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 2-Stroke Outboards

Yamaha 4-Stroke Outboards

Technical Specifications

Package Contents

For Yamaha 2-Stroke Models (Replaces 6H3-W0078-02-00)

• 1 x Water Pump Housing (6H3-44311-00-00)
• 1 x Impeller (6H2-44352-00-00)
• 1 x Insert Cup (663-44322-00-00)
• 1 x Wear Plate (6H3-44323-00-00)
• 1 x Water Pump Gasket (688-44316-01-00)
• 1 x Water Pump Gasket (6H2-44315-00-00)
• 1 x Outer Plate Gasket (6H2-44324-00-00)
• 1 x Impeller Key (90280-03M03-00)
• 1 x O-Ring (93210-46044-00)
• 2 x Bolt with washer (90119-08M14-00)
• 2 x Bolt with washer (90119-08M33-00)

For Yamaha 4-Stroke Models (Replaces 68V-W0078-00-00)

• 1 x Water Pump Housing (61A-44311-01)
• 1 x Impeller (6E5-44352)
• 1 x Insert Cup (61A-44322)
• 1 x Wear Plate (68V-44323)
• 1 x Gasket (6E5-44315)
• 1 x Impeller Key (90280-04M05)
• 1 x O-Ring (93210-37M67)
• 1 x O-Ring (93210-86M38)
• 4 x Bolts (91290-08045)
• 2 x Dowel Pins (93606-12019)
• 4 x Washers (90209-08M02)

Installation Guide

1. Safety First: Disconnect the engine's battery before starting any work.
2. Drain Gear Lube: Place a drain pan under the lower unit and remove the drain/fill screws to drain the gear lube.
3. Remove Lower Unit: Unbolt the lower unit (gearcase) from the outboard's midsection and carefully lower it.
4. Access Water Pump: With the lower unit removed, locate and unbolt the water pump housing.
5. Disassemble Pump: Remove the old housing, impeller, gaskets, wear plate, and insert cup. Note the orientation of the old impeller vanes.
6. Clean Surfaces: Thoroughly clean all mating surfaces where gaskets will sit, removing any old sealant or debris.
7. Install New Components: Install the new wear plate, gaskets, and insert cup into the housing.
8. Install Impeller: Slide the new woodruff key onto the driveshaft flat spot, then slide the new impeller on, turning the shaft clockwise to bed the vanes correctly.
9. Reassemble Housing: Place the new housing over the impeller and tighten the bolts to the manufacturer's specified torque.
10. Re-install Lower Unit: Carefully guide the lower unit back into place, ensuring the driveshaft, shift shaft, and water tube align. Secure with bolts.
11. Refill Gear Lube: Pump fresh marine gear lube into the lower unit through the bottom hole until it seeps out the top hole. Re-install both screws.
12. Test Operation: Reconnect the battery. Start the engine in water and confirm that a steady stream of water is exiting the tell-tale port.

Troubleshooting & FAQ

How do I confirm this kit fits my engine?
The most reliable method is to match your engine's model and year to the compatibility charts on this page. For absolute certainty, cross-reference the OEM part number stamped on your existing water pump components with the numbers listed in our "Part Number Cross-Reference" table.

What are the signs that my water pump impeller needs replacement?
Common signs of a failing impeller include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, or reduced engine performance. It is recommended to replace the impeller as part of regular maintenance, typically every 1-2 years or 100-200 hours, regardless of visible symptoms.

What is the difference between the 2-stroke and 4-stroke kits in this listing?
The kits are designed for different engine series and contain different components. The 2-stroke kit (replaces 6H3-W0078-02-00) fits specified 50-70 HP models, while the 4-stroke kit (replaces 68V-W0078-00-00) fits specified F75-F115 HP models. Ensure you are selecting the kit that matches your engine type by checking the compatibility tables.

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.