Water Pump Impeller Repair Kit for Yamaha 4HP/5HP Outboards – Replaces 6E0-W0078-A2-00
Water Pump Impeller Repair Kit for Yamaha 4HP/5HP Outboards – Replaces 6E0-W0078-A2-00 is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
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Water Pump Impeller Repair Kit for Yamaha 4HP/5HP Outboards – Repla...
Water Pump Impeller Repair Kit for Yamaha 4HP/5HP Outboards – Replaces 6E0-W0078-A2-00 is backordered and will ship as soon as it is back in stock.
Product Details
This water pump impeller repair kit is designed for servicing the lower-unit water pump on selected Yamaha 4HP and 5HP outboard motors, including listed 2-stroke models and selected 4-stroke F4 models. It replaces the Yamaha reference 6E0-W0078-A2-00 and other listed reference numbers when the engine model, year, and serial-number conditions match.
The kit is listed as a replacement for Yamaha references 6E0-W0078-A2-00, 6E0-W0078-02-00, 6E0-W0078-01-00, and 6E0-W0078-00-00, as well as Sierra reference 18-3016. These references should be verified against the original assembly before ordering.
- Replacement water pump service kit for selected Yamaha and Mariner outboards.
- Includes an impeller, housing and related gaskets, plates, seal damper, pin, and mounting bolts.
- Neoprene rubber impeller with stainless-steel pump components as listed.
- Confirm the complete engine model, year, stroke, and serial-number conditions before installation.
Part Number Matrix
Use the following references to compare the replacement kit with the original or previously installed part. Part-number matching alone does not replace model and serial-number verification.
| 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 |
Engine & Model Compatibility
Compatibility applies only to the models and conditions listed below. Check the identification plate, service information, and serial number on your engine before purchasing.
| Brand | Model | Rated HP | Stroke | Years | Notes |
|---|---|---|---|---|---|
| Yamaha | 4A, 4AC, 4ACMH, 4CMH | 4 | 2-Stroke | 1984–1999 | Verify the exact model designation. |
| Yamaha | 4MLHU, 4MLHU2, 4MSHU, 4MSHU2 | 4 | 2-Stroke | 1996 | Verify the exact model designation. |
| Yamaha | 5C, 5CM, 5CMH | 5 | 2-Stroke | 1984–2002 | Verify the exact model designation. |
| Yamaha | 5MLHU, 5MLHU2, 5MSHU, 5MSHU2 | 5 | 2-Stroke | 1996 | Verify the exact model designation. |
| Yamaha | F4 | 4 | 4-Stroke | 1999–2008 | Verify the exact model and year. |
| Mariner | 4A (6E0) | 4 | 2-Stroke | Not specified | For models with serial-number prefix 6E0. |
| Mariner | 5C (6E3) | 5 | 2-Stroke | Not specified | For models with serial-number prefix 6E3. |
| Mariner | 96325T, 96325M | 4, 5 | 2-Stroke | Not specified | Only where the serial-number conditions 6E0 or 6E3 apply. |
Technical Specifications
- Product Type
- Water pump impeller repair kit
- Application
- Lower-unit water pump service
- Installation
- Replacement installation; compare the original parts before assembly
- Materials
- Neoprene rubber impeller and stainless-steel pump components as listed
- Dimensions
- 152 × 102 × 51 mm (6 × 4 × 2 inches)
- Weight
- 0.18 kg (0.4 lb)
- Product Status
- Aftermarket replacement, not a Yamaha or Mariner genuine OEM component
What’s in the Box
- 1 × Water pump housing — Yamaha reference 6E0-44311-00-00
- 1 × Water pump gasket — Yamaha reference 6E0-44315-A0-00
- 1 × Cartridge insert — Yamaha reference 6E0-44322-02-00
- 1 × Cartridge outer plate — Yamaha reference 6E0-44323-00-00
- 1 × Impeller — Yamaha reference 6E0-44352-00-00
- 1 × Water seal damper 2 — Yamaha reference 6E0-44366-00-00
- 1 × Dowel pin — Yamaha reference 93604-09066-00
- 4 × Bolts — Yamaha references 97080-06045-00 or 97095-06045-00
Installation Notes
- Stop the engine, remove the ignition key or disconnect the ignition source, and follow the safety procedures in the applicable service manual.
- Place the outboard securely and shift it into neutral where required by the service procedure.
- Remove the lower-unit mounting hardware and carefully separate the gearcase from the upper driveshaft housing.
- Remove the water pump housing and note the orientation of the existing impeller, gasket, plates, and cartridge components.
- Remove the old impeller and service parts, then clean the mating surfaces and inspect the driveshaft, keyway, water tube, and housing for damage.
- Install the replacement gasket, plates, cartridge insert, and other kit components in the same order and orientation as specified by the service manual.
- Install the impeller on the driveshaft and orient the vanes as specified for the engine. Do not force the impeller or reuse damaged fasteners.
- Install the water pump housing and tighten the bolts to the manufacturer’s specified torque.
- Reassemble the lower unit, ensuring correct alignment of the driveshaft, shift mechanism, and water tube.
- Test the engine only in an appropriate water or flushing setup and confirm proper cooling-water flow before normal operation.
Troubleshooting & FAQ
How do I know if this kit fits my engine?
Compare the engine brand, exact model, horsepower, stroke, year, and serial-number conditions with the compatibility table. Also compare the original water-pump assembly and part number. If any identifying detail differs, consult the engine service information before ordering.
What are the signs of a failing water-pump impeller?
Common signs include weak or missing tell-tale water flow, overheating warnings, steam, or other cooling-system symptoms. Stop operating the engine if overheating is suspected and inspect the cooling system before further use.
How often should the impeller be replaced?
Replacement intervals depend on the engine manufacturer’s maintenance schedule, operating hours, storage conditions, and whether the engine is used in saltwater, silt, or sandy water. Follow the applicable service manual and replace the impeller when inspection shows wear or damage.
Is this an OEM part?
No. This is an aftermarket replacement kit. Yamaha, Mariner, and Sierra names and part numbers are used only to identify application and reference compatibility where applicable.
How fast is shipping and what does it cost?
Shipping availability, delivery time, and cost are calculated according to the destination and the options shown at checkout.
What warranty and return policy applies?
Warranty and returns are subject to the seller’s current policy. Contact support with the order details and product condition before returning an item.
Safety & Important Information
- Verify the complete engine model, year, stroke, and serial-number conditions before purchase.
- Compare the replacement components with the original parts before installation.
- Do not operate an outboard with inadequate cooling-water flow or suspected overheating.
- Use the manufacturer’s service manual for torque values, disassembly procedures, and final inspection.
- This is an aftermarket replacement kit and is not a genuine OEM component.
- Professional installation is recommended when the required service procedures are unfamiliar.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for fit, function, and dependable service use.
- Global Fulfillment — Delivery options and estimated transit times are shown according to the destination at checkout.
- Manufacturer-Direct Value — We aim to provide practical replacement solutions with clear application information.
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