Water Pump Impeller Repair Kit – Fits Yamaha 4HP/5HP Outboard Motors (Replaces 6E0-W0078-A2-00)
This water pump impeller repair kit provides the necessary components to service the lower unit water pump on Yamaha 2-stroke 4HP (1984–1999) and 5HP (1984–2002) models, as well as 4-stroke F4 (1999–2008) outboards.
It serves as a direct replacement for multiple Yamaha and aftermarket part numbers, ensuring a precise fit for a complete and reliable water pump service.
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Direct Replacement Installation: Designed to OEM specifications for a direct fit without modifications.
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Complete Service Kit: Includes the impeller, housing, gaskets, plates, and hardware required for a full overhaul.
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Durable Materials: Constructed with a robust neoprene rubber impeller and stainless steel plates for longevity and corrosion resistance.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Yamaha |
6E0-W0078-A2-00 |
| Yamaha |
6E0-W0078-02-00 |
| Yamaha |
6E0-W0078-01-00 |
| Yamaha |
6E0-W0078-00-00 |
| Sierra |
18-3016 |
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.
| Brand |
Model |
Rated HP |
Stroke |
Years |
OEM Part No. |
Notes |
| Yamaha |
4A, 4AC, 4ACMH, 4CMH |
4 |
2-Stroke |
1984–1999 |
6E0-W0078-A2-00 |
|
| Yamaha |
4MLHU, 4MLHU2, 4MSHU, 4MSHU2 |
4 |
2-Stroke |
1996 |
6E0-W0078-A2-00 |
|
| Yamaha |
5C, 5CM, 5CMH |
5 |
2-Stroke |
1984–2002 |
6E0-W0078-A2-00 |
|
| Yamaha |
5MLHU, 5MLHU2, 5MSHU, 5MSHU2 |
5 |
2-Stroke |
1996 |
6E0-W0078-A2-00 |
|
| Yamaha |
F4 |
4 |
4-Stroke |
1999–2008 |
6E0-W0078-A2-00 |
|
Confirm your engine model/year in the table below.
| Brand |
Model |
Rated HP |
Stroke |
OEM Part No. |
Notes |
| Mariner |
4A(6E0) |
4 |
2-Stroke |
6E0-W0078-A2-00 |
Models with Serial Number 6E0 |
| Mariner |
5C(6E3) |
5 |
2-Stroke |
6E0-W0078-A2-00 |
Models with Serial Number 6E3 |
| Mariner |
96325T, 96325M |
4, 5 |
2-Stroke |
6E0-W0078-A2-00 |
Only with Serial Number 6E0 & 6E3 |
Technical Specifications
| Specification |
Value |
| Product Type |
Water Pump Impeller Repair Kit |
| Installation |
Direct replacement |
| Housing Material |
Neoprene rubber impeller, stainless steel plates |
| Dimensions |
152 × 102 × 51 mm (6 × 4 × 2 inches) |
| Weight |
0.18 kg (0.4 lb) |
| Other Technical Attributes |
High-quality materials designed to OEM specifications |
Package Contents
- 1 x Water Pump Housing (6E0-44311-00-00)
- 1 x Water Pump Gasket (6E0-44315-A0-00)
- 1 x Cartridge Insert (6E0-44322-02-00)
- 1 x Cartridge Outer Plate (6E0-44323-00-00)
- 1 x Impeller (6E0-44352-00-00)
- 1 x Water Seal Damper 2 (6E0-44366-00-00)
- 1 x Dowel Pin (93604-09066-00)
- 4 x Bolt (97080-06045-00/97095-06045-00)
Installation Guide
- Disconnect the shift linkage and remove the bolts securing the lower unit (gearcase). Carefully lower the unit away from the outboard.
- Locate and unbolt the water pump housing.
- Remove the old impeller, gaskets, and wear plates, noting their orientation for reassembly.
- Thoroughly clean all mating surfaces, removing any old gasket material or debris.
- Install the new cartridge insert and then place the new outer plate and gasket.
- Slide the new impeller onto the driveshaft. Turn the driveshaft clockwise while pushing down to seat the impeller vanes correctly.
- Position the new housing over the impeller and tighten the bolts to the manufacturer's recommended torque specification.
- Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are correctly aligned.
- Reconnect the shift linkage, and test the engine with a proper water supply before operation.
Troubleshooting & FAQ
Q: How do I confirm this kit fits my specific engine?
A: Please check the "Compatible Engine Models" tables on this page. Match your engine's brand, model, horsepower, and year range. For Yamaha and Mariner models, cross-referencing the serial numbers listed in the notes can also confirm fitment.
Q: What are the signs of a failing water pump impeller?
A: Common symptoms include a weak or intermittent water stream from the "telltale" outlet, engine overheating alarms, or a visible reduction in cooling performance.
Q: How often should the water pump impeller be replaced?
A: 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, depending on usage conditions (e.g., saltwater vs. freshwater).
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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.