Water Pump Service Kit with Housing – Johnson/Evinrude 20–35 HP 2-Stroke, Replaces 393630
Water Pump Service Kit with Housing – Johnson/Evinrude 20–35 HP 2-Stroke, Replaces 393630 is backordered and will ship as soon as it is back in stock.
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Water Pump Service Kit with Housing – Johnson/Evinrude 20–35 HP 2-S...
Water Pump Service Kit with Housing – Johnson/Evinrude 20–35 HP 2-Stroke, Replaces 393630 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump service kit with housing is designed for selected Johnson/Evinrude 20–35 HP two-stroke outboard engines. It is intended for servicing the complete water pump assembly on applicable two-cylinder crossflow engines with through-propeller exhaust and a one-piece gearcase.
The kit replaces Johnson/Evinrude OEM reference 393630. It includes a replacement pump housing together with the water-pump service components required for the applicable installation. Confirm the engine model, year, gearcase configuration, and existing part number before ordering.
- Aftermarket replacement water pump service kit with housing.
- For applicable Johnson/Evinrude two-stroke 20–35 HP outboards.
- Designed for the 20–35 HP two-cylinder crossflow application with through-propeller exhaust and one-piece gearcase.
- Use the components appropriate to the specific engine variation during installation.
Part Number Matrix
The following are manufacturer and aftermarket reference numbers associated with this application. Reference numbers are provided for identification and cross-checking only; they do not replace model-specific fitment verification.
| Brand | Reference Number | Reference Type |
|---|---|---|
| Johnson/Evinrude | 393630 | OEM reference |
| Johnson/Evinrude | 0777803 | OEM reference |
| Johnson/Evinrude | 0393509 | OEM reference |
| Johnson/Evinrude | 0390344 | OEM reference |
| Johnson/Evinrude | 0391636 | OEM reference |
| Johnson/Evinrude | 437909 | OEM reference |
| Sierra | 18-3382 | Aftermarket reference; with housing |
| Sierra | 18-3381 | Aftermarket reference |
| GLM | 12070 | Aftermarket reference |
| Mallory Marine | 9-48205, 9-48211 | Aftermarket references |
| SEI | 96-362-01K | Aftermarket reference |
Engine & Model Compatibility
Fitment applies to the listed Johnson/Evinrude two-stroke applications when the engine also matches the specified cylinder, exhaust, and gearcase conditions.
| Brand | Application | Rated HP | Stroke | Years | Engine Conditions | OEM Reference |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | Various | 20 | 2-Stroke | 1985 and later | Applicable two-cylinder crossflow configuration with through-propeller exhaust and one-piece gearcase | 393630 |
| Johnson/Evinrude | Various | 25 | 2-Stroke | 1985 and later | Applicable two-cylinder crossflow configuration with through-propeller exhaust and one-piece gearcase | 393630 |
| Johnson/Evinrude | Commercial | 25 | 2-Stroke | 1998–2001 | Applicable commercial model with matching water pump and one-piece gearcase configuration | 393630 |
| Johnson/Evinrude | Various | 30 | 2-Stroke | 1980–1982 | Applicable two-cylinder crossflow configuration with through-propeller exhaust and one-piece gearcase | 393630 |
| Johnson/Evinrude | Various | 30 | 2-Stroke | 1983 and later | 2-cylinder models with through-propeller exhaust and one-piece gearcase | 393630 |
| Johnson/Evinrude | Various | 35 | 2-Stroke | 1980–1982 | Applicable two-cylinder crossflow configuration with through-propeller exhaust and one-piece gearcase | 393630 |
| Johnson/Evinrude | Various | 35 | 2-Stroke | 1983 and later | 2-cylinder models with through-propeller exhaust and one-piece gearcase | 393630 |
Technical Specifications
- Product Type
- Water pump service kit with housing
- Application
- Johnson/Evinrude 20–35 HP two-stroke outboard engines
- Engine Configuration
- Applicable two-cylinder crossflow engines with through-propeller exhaust and one-piece gearcase
- Housing
- Replacement water pump housing included
- OEM Reference
- 393630
- Installation
- Direct replacement service installation; verify the individual engine application before fitting
What’s in the Box
This is a water pump service kit with housing. Package components are supplied for the applicable water pump service and may include the replacement housing, impeller, pump plate or wear plate, gaskets, seals, grommet, O-rings, key, and installation hardware required by the matching engine configuration.
- 1 x Replacement water pump housing
- 1 x Water pump impeller
- Water pump plate or wear plate, as applicable to the engine configuration
- Matching water pump gaskets and seals
- Applicable grommet, O-rings, key, and installation hardware
Compare the supplied components with the parts removed from your original assembly before installation. Do not combine components from a different water pump application.
Installation Notes
- Disconnect the battery and follow the outboard manufacturer’s safety procedures.
- Remove the lower unit according to the service instructions for your exact engine model.
- Remove the water pump cover or housing and inspect the driveshaft, keyway, pump plate, seals, and mating surfaces.
- Clean all mating surfaces and remove debris before installing replacement components.
- Install the replacement plate, gasket, impeller, key, housing, seals, and related hardware in the correct order for the engine configuration.
- Rotate the driveshaft in the correct direction while installing the housing over the impeller.
- Reinstall the lower unit, tighten fasteners to the manufacturer’s specified torque, and restore the gearcase lubricant if it was drained.
- Run the engine using the correct water supply procedure and confirm a steady cooling-water telltale stream before normal operation.
Troubleshooting & FAQ
How do I confirm fitment?
Check the engine brand, exact model number, year, horsepower, stroke, cylinder count, exhaust arrangement, and gearcase type. This kit is for the listed Johnson/Evinrude 20–35 HP two-stroke applications using the matching through-propeller-exhaust and one-piece-gearcase configuration. Also compare the original water pump reference with 393630.
Does this kit include a housing?
Yes. This listing is for the water pump service kit with housing. Do not substitute a without-housing service kit when your repair requires the housing included in this listing.
What are the signs of a failing water pump impeller?
Common signs include a weak or missing telltale stream, overheating, steam, or an impeller that is cracked, brittle, deformed, or worn. Inspect the complete pump assembly whenever cooling performance is reduced.
How often should the impeller be replaced?
Replacement intervals depend on operating hours, storage conditions, and water quality. Inspect the impeller during routine service and replace it whenever wear, cracking, hardening, deformation, or damage is found.
Can I install this kit myself?
Installation requires removal of the lower unit and correct water pump alignment. Owners with suitable mechanical experience and the correct service information may perform the work; professional installation is recommended if you are not familiar with outboard lower-unit service.
Is this an OEM part?
No. This is an aftermarket replacement kit. Johnson/Evinrude and the other brand names and reference numbers are used only to identify the intended application and compatibility references.
Safety & Important Information
- Verify the complete engine application before ordering, including model, year, horsepower, stroke, cylinder count, exhaust arrangement, and gearcase type.
- Compare the original water pump assembly and reference number with the listed application.
- Do not operate an outboard with insufficient cooling-water flow.
- Follow the engine manufacturer’s service, torque, lubrication, and testing procedures.
- This is an aftermarket replacement, not an OEM component.
About Sea Sierra
- Marine Replacement Parts — Replacement components for practical outboard maintenance and repair.
- Application-Focused Listings — Product references and fitment details are provided to support accurate part selection.
- Service Support — Verify your engine information and original component before installation.
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