Water Pump Impeller for Johnson/Evinrude 8, 9.9 & 15 HP Outboards – Replaces 386084
Water Pump Impeller for Johnson/Evinrude 8, 9.9 & 15 HP Outboards – Replaces 386084 is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller for Johnson/Evinrude 8, 9.9 & 15 HP Outboar...
Water Pump Impeller for Johnson/Evinrude 8, 9.9 & 15 HP Outboards – Replaces 386084 is backordered and will ship as soon as it is back in stock.
Product Details
This replacement water pump impeller is designed for selected Johnson/Evinrude outboard water pump applications rated at 8, 9.9, and 15 HP. Catalog references identify the corresponding OEM application as 1974 and later. Use your engine model information and the part number on your original impeller to confirm fitment before ordering.
The impeller replaces Johnson/Evinrude/OMC part number 386084 and is also listed in aftermarket cross-reference information as Sierra 18-3050. It is intended for the raw-water cooling pump in the outboard lower unit.
- Replacement water pump impeller for selected Johnson/Evinrude outboards.
- Application range: 8, 9.9, and 15 HP models identified in the referenced catalog.
- Supports proper cooling-water circulation when correctly matched and installed.
- Sold as one impeller; additional pump components are not included unless specifically stated.
Part Number Matrix
Use the references below to compare the impeller with your existing part. Part-number matching should be combined with confirmation of the complete engine model and serial information.
| Brand or Reference | Part Number |
|---|---|
| Johnson/Evinrude | 386084 / 0386084 |
| OMC | 386084 |
| Sierra aftermarket reference | 18-3050 |
Engine & Model Compatibility
The referenced catalog lists part number 386084 for Johnson/Evinrude water pump impeller applications covering 8, 9.9, and 15 HP outboards from 1974 onward. The information below is an application guide rather than a substitute for checking the exact model, year, and serial-number range.
| Brand | Rated HP | Catalog Application Range | Reference Part No. | Fitment Note |
|---|---|---|---|---|
| Johnson/Evinrude | 8 | 1974 and later applications listed for 386084 | 386084 | Confirm the exact model and serial range. |
| Johnson/Evinrude | 9.9 | 1974 and later applications listed for 386084 | 386084 | Confirm the exact model and serial range. |
| Johnson/Evinrude | 15 | 1974 and later applications listed for 386084 | 386084 | Confirm the exact model and serial range. |
Important: Horsepower and year alone may not establish fitment for every engine configuration. Compare the original impeller, keyway, pump housing, and manufacturer part number before installation.
Technical Specs
- Product Type
- Water pump impeller
- Application
- Selected Johnson/Evinrude outboard raw-water cooling pumps
- Reference OEM Number
- 386084
- Catalog Application
- 8, 9.9, and 15 HP; 1974 and later applications listed for this reference
- Approximate Catalog Dimensions
- 1.50 inch outside diameter and 0.500 inch inside diameter; verify against the original part before ordering
- Key Information
- Catalog information identifies a separate impeller-key reference for this application. Confirm whether your service requires a replacement key before installation.
- Installation Location
- Water pump assembly in the outboard lower unit
What’s in the Box
- 1 x Water pump impeller
The listing is for the impeller only. A key, gasket, seals, wear plate, pump housing, and other water-pump components are not included unless expressly shown or stated in the applicable order details.
Installation Notes
- Before service, make sure the engine is switched off, secured, and cool. Follow the service procedure for your exact outboard.
- Remove the lower unit and water-pump cover according to the manufacturer's instructions.
- Remove the old impeller and note the position of the drive key and the direction in which the vanes are bent.
- Inspect the pump housing, wear plate, drive key, seals, and related components for wear or damage.
- Clean debris from the pump assembly before installing the replacement impeller.
- Install the drive key correctly and slide the impeller onto the shaft, ensuring that the key engages the hub.
- Use a lubricant approved for the application if required by the service manual. Do not use a lubricant that may damage the impeller material.
- Fit the pump cover while turning the shaft in the normal operating direction so the vanes fold correctly. Follow the engine manufacturer's specified rotation and procedure.
- Replace gaskets or seals when required by the service manual or when inspection shows damage.
- Reinstall the lower unit, tighten fasteners to the manufacturer's specifications, and verify that the water tube and shift mechanism are correctly aligned.
- Run the engine only in an appropriate test-water setup and confirm cooling-water flow and normal operating temperature before returning the boat to service.
Troubleshooting & FAQ
How do I know if this impeller will fit my engine?
First compare your original part number with 386084 and check the engine's complete Johnson/Evinrude model and serial information. The referenced application range is 8, 9.9, and 15 HP outboards from 1974 onward, but horsepower and year alone do not confirm every configuration. Also compare the impeller dimensions, hub, keyway, and pump housing.
What are common signs of a failing water pump impeller?
Possible signs include overheating, reduced or intermittent cooling-water flow, and little or no water from the tell-tale outlet. An impeller can also become hard, cracked, worn, or damaged after prolonged storage or operation with inadequate water supply.
How often should an impeller be replaced?
Replacement intervals depend on the engine manufacturer's maintenance schedule and operating conditions. Inspect the impeller during scheduled water-pump service and replace it when it is worn, damaged, hardened, deformed, or when cooling performance is reduced. Saltwater, sand, silt, and extended storage may increase service requirements.
Does the package include the impeller key?
No. This listing is for one impeller only. The referenced catalog identifies a separate key for this application, so inspect and reuse the existing key only if it is in serviceable condition and the service manual permits it.
What is the correct orientation of the impeller vanes?
Install the impeller so the vanes fold in the direction required by the pump's normal operating rotation. Use the service manual for your exact engine and rotate the shaft as specified while installing the pump cover.
Is this part OEM or aftermarket?
This listing is for an aftermarket replacement impeller. The OEM and aftermarket numbers shown are reference numbers used to help identify the intended application; this product is not represented as a genuine Johnson/Evinrude or OMC-branded part.
Can I install this without replacing the other water-pump parts?
That depends on inspection results and the manufacturer's service procedure. Check the pump housing, wear plate, key, gaskets, seals, and related components while the assembly is open. Replace worn or damaged parts as required for your engine.
Safety & Important Info
- Verify the complete engine model, year, serial information, and original part number before ordering.
- Do not rely on horsepower alone to establish fitment.
- Do not operate an outboard without an adequate water supply for cooling.
- Follow the manufacturer's service instructions and fastener-torque specifications.
- Professional installation is recommended if you are not familiar with outboard lower-unit or water-pump service.
About Sea Sierra
- Marine Replacement Parts — We provide aftermarket marine components for common service and repair applications.
- Application-Focused Information — Use the listed reference numbers together with your engine's exact model and serial information to select the correct part.
- Service Support — Review the installation requirements for your specific engine before beginning water-pump service.
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