Water Pump Impeller Kit Without Housing – Fits Johnson/Evinrude 4–8 HP 2-Stroke Outboards – Replaces 396644
Water Pump Impeller Kit Without Housing – Fits Johnson/Evinrude 4–8 HP 2-Stroke Outboards – Replaces 396644 is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Kit Without Housing – Fits Johnson/Evinrude 4–8...
Water Pump Impeller Kit Without Housing – Fits Johnson/Evinrude 4–8 HP 2-Stroke Outboards – Replaces 396644 is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit is an aftermarket cooling-system service kit for selected Johnson/Evinrude 2-stroke outboard engines from 4 to 8 HP. It is supplied without the water-pump housing and is intended to replace the service components inside the existing compatible pump housing.
The kit replaces Johnson/Evinrude/OMC OEM part number 396644 and corresponds to Sierra part number 18-4529. The documented fitment covers specific 4 HP, 5 HP, 6 HP, and 8 HP applications; verify the engine model, year, and existing pump components before ordering.
- Includes the impeller assembly, impeller housing plate, impeller housing cup, gaskets, O-ring, grommets, drive key, and screws.
- Designed for service of the existing compatible water-pump housing; the housing itself is not included.
- Suitable for the listed gasoline-powered Johnson/Evinrude marine outboard applications.
Part Number Matrix
Use the following verified reference numbers when comparing the replacement kit with your existing parts.
| Brand or Catalog | Part Number | Reference |
|---|---|---|
| Johnson/Evinrude/OMC | 396644 | OEM replacement reference |
| Sierra | 18-4529 | Water pump kit without housing |
Engine & Model Compatibility
Fitment is based on the documented Johnson/Evinrude 2-stroke applications below. Model names and production details can vary, so compare your engine identification label and existing water-pump components before installation.
| Brand | Rated HP | Stroke | Years | OEM Reference | Housing |
|---|---|---|---|---|---|
| Johnson/Evinrude | 4 | 2-Stroke | 1986–1992 | 396644 | Not included |
| Johnson/Evinrude | 5 | 2-Stroke | 1980–1983; 1996–2001 | 396644 | Not included |
| Johnson/Evinrude | 6 | 2-Stroke | 1984–2001; 2003–2005 | 396644 | Not included |
| Johnson/Evinrude | 8 | 2-Stroke | 1980–2001; 2003–2005 | 396644 | Not included |
Technical Specs
- Product Type
- Water pump impeller kit without housing
- Application
- Selected Johnson/Evinrude 2-stroke outboards, 4–8 HP
- OEM Replacement Reference
- 396644
- Aftermarket Catalog Reference
- Sierra 18-4529
- Housing
- Not included; reuse the existing compatible housing
- Installation
- Replacement of compatible water-pump service components
- Fuel Type
- Gasoline marine outboard engines
- Package Contents
- Impeller assembly, plate, cup, gasket, O-ring, grommets, drive key, and screws
What’s in the Box
- 1 × Drive Key — aftermarket reference 18-3026; OEM reference 331130
- 1 × Grommet — aftermarket reference 18-1827; OEM reference 321129
- 1 × Grommet — aftermarket reference 18-3329; OEM reference 302497
- 4 × Screws — aftermarket reference 18-4277; OEM reference 324430
- 1 × Impeller Housing Plate — aftermarket reference 18-4578; OEM reference 324640
- 1 × Impeller Housing Cup — aftermarket reference 18-4551; OEM reference 324641
- 2 × Impeller Housing Gaskets — aftermarket reference 18-99156; OEM reference 325040
- 1 × Impeller Assembly — aftermarket reference 18-3091; OEM reference 389576
- 1 × O-Ring — aftermarket reference 18-7413; OEM reference 303191
- Water-pump housing not included.
Installation Notes
- For safety, stop the engine, disconnect the battery where applicable, and remove the spark plug wires before servicing.
- Place the outboard transmission in neutral and remove the fasteners securing the lower unit.
- Carefully lower and separate the gearcase from the upper section, taking care not to damage the shift shaft or water tube.
- Locate the water-pump assembly on top of the gearcase and remove the housing fasteners.
- Remove the old impeller, drive key, gaskets, O-ring, plate, cup, and related service components as applicable.
- Inspect the existing housing for cracks, scoring, distortion, or excessive wear. Replace the housing if it is not serviceable.
- Clean all mating surfaces and remove old gasket material and debris.
- Install the new plate, gaskets, O-ring, drive key, and impeller. Apply only the lubricant recommended by the engine or service-manual instructions.
- Fit the impeller into the existing compatible housing, rotating the driveshaft in the specified direction so the vanes seat correctly.
- Reinstall the housing and tighten the fasteners to the engine manufacturer's specified torque.
- Reattach the lower unit, ensuring the driveshaft, shift shaft, and water tube are properly aligned.
- Run the engine in an appropriate water supply and confirm a steady cooling-water tell-tale stream before normal operation.
Troubleshooting & FAQ
How do I confirm this kit fits my specific engine?
Confirm that your Johnson/Evinrude outboard is one of the listed 2-stroke 4–8 HP applications and that your existing water-pump components correspond to OEM reference 396644 or Sierra reference 18-4529. Check the exact model and year on the engine identification label before ordering.
Does this kit include the water-pump housing?
No. This is a water-pump service kit without housing. It includes the listed internal service components and is intended for use with the existing compatible housing.
What are the signs of a worn water-pump impeller?
Common signs include a weak or intermittent tell-tale stream, overheating, steam from the exhaust, or visible cracking, brittleness, or permanently curved impeller vanes. Inspect the housing and related components at the same time.
How often should the impeller be replaced?
Inspect the water-pump components during routine seasonal maintenance and replace the impeller when the vanes show wear, cracking, hardening, or permanent deformation. Service intervals should follow the engine manufacturer's recommendations and operating conditions.
Is this an OEM part?
This listing is for an aftermarket replacement kit. The listed OEM and catalog numbers are provided as compatibility references only and do not indicate that the replacement is manufactured by Johnson, Evinrude, or OMC.
Can I reuse my old water-pump housing?
The housing may be reused only if it is the correct compatible housing and passes inspection. Do not reuse a housing that is cracked, warped, heavily scored, or excessively worn.
What is the return policy?
Return eligibility and timing depend on the current store policy. Review the applicable policy before installation; installed, used, or damaged parts may have different return conditions.
Safety & Important Info
- Verify the engine model, year, horsepower, stroke, and existing part numbers before purchase.
- Verify that your original housing and related components match the kit configuration.
- This is an aftermarket replacement kit, not an OEM component.
- Follow the engine service manual for torque values, lubricants, alignment procedures, and testing.
- Professional installation is recommended when lower-unit or water-pump service procedures are unfamiliar.
About Sea Sierra
- Marine Replacement Parts — Practical aftermarket components for routine outboard maintenance and repair.
- Fitment-Focused Listings — Reference numbers and application details are provided to help customers compare their existing parts.
- Support Before Installation — Confirm compatibility before installing or modifying the part.
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