Water Pump Impeller Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 438592, 433548, 433549)
Water Pump Impeller Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 438592, 433548, 433549) 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
Free standard shipping on all orders under 1 KG
Water Pump Impeller Kit – Fits Johnson/Evinrude 40-50 HP (Replaces ...
Product Details
This complete Water Pump Impeller Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 438592, 433548, 433549) is designed for Johnson/Evinrude 40-50 HP 2-Stroke engines from 1989–2005 and 25-35 HP Jet models from 1992 and up. It provides all necessary components to restore the engine's cooling system for optimal performance and reliability.
It serves as a direct replacement for Johnson/Evinrude part numbers 438592, 433548, 433549, and 777805, as well as aftermarket references Sierra 18-3454, GLM 12245, and 18-3394.
- Installs in the lower unit of the outboard motor.
- Kit includes the pump housing, impeller, wear plate, and all required gaskets, seals, and bolts.
- Features a new style sealed bearing, eliminating the need to align the grease hole on older models.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Johnson/Evinrude | 438592 / 0438592 |
| Johnson/Evinrude | 433548 / 0433548 |
| Johnson/Evinrude | 433549 / 0433549 |
| Johnson/Evinrude | 777805 / 0777805 |
| Sierra | 18-3454 |
| GLM | 12245 |
| Aftermarket | 18-3394 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is specifically designed for the following Johnson/Evinrude outboard and jet drive models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | 2 Cylinder | 40 | 2-Stroke | 1989–1998 | 438592 | Small Housing |
| Johnson/Evinrude | 2 Cylinder | 40 | 2-Stroke | 1999–2005 | 438592 | |
| Johnson/Evinrude | 2 Cylinder | 45 | 2-Stroke | 1989–2005 | 438592 | |
| Johnson/Evinrude | 2 Cylinder | 48 | 2-Stroke | 1989–1996 | 438592 | |
| Johnson/Evinrude | 2 Cylinder | 50 | 2-Stroke | 1989–1999 | 438592 | Small Housing |
| Johnson/Evinrude | Jet Drive | 35 | 2-Stroke | 1992–1993 | 438592 | |
| Johnson/Evinrude | Jet Drive | 25 | 2-Stroke | 1995–up | 438592 | |
| Johnson/Evinrude | Jet Drive | 30 | 2-Stroke | 1995–up | 438592 |
Technical Specs
- Product Type
- Water Pump Impeller Kit with Housing
- Installation
- Lower Unit
- Fuel Type
- Gasoline
What’s in the Box
- 1 x Impeller (432941)
- 1 x Pump Cup/Insert Cup (340619)
- 1 x Wear Plate (341038)
- 1 x Water Pump Gasket (336530)
- 1 x Woodruff Key (334897)
- 1 x O-Ring (331188)
- 1 x O-Ring (310584)
- 1 x Seal (324981)
- 1 x Grommet (333758)
- 1 x Grommet/Adapter (331732)
- 1 x Pump Housing (438544)
- 4 x Bolt (302325)
Installation Notes
- Disconnect the negative battery cable and ensure the engine is off.
- Disconnect the shift linkage connecting the engine to the lower unit.
- Remove the bolts securing the gearcase (lower unit) to the engine leg.
- Carefully lower and remove the gearcase to access the water pump.
- Unscrew the bolts on the water pump assembly and remove the old housing and impeller.
- Clean the mating surfaces of the gearcase and driveshaft.
- Install the new wear plate, gasket, and Woodruff key.
- Slide the new impeller onto the driveshaft, rotating it in the direction of engine rotation.
- Install the new O-rings and seals, applying marine grease where needed.
- Place the new housing over the impeller and bolt it down securely.
- Reinstall the gearcase onto the engine leg, ensuring the driveshaft and water tube align.
- Reconnect the shift linkage and test for proper gear engagement.
Troubleshooting & FAQ
How often should the water pump impeller be replaced?
For most recreational boats, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation, whichever comes first. Frequent use in sandy or silty water may require more frequent replacement.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or intermittent water stream from the "telltale" outlet, engine overheating at idle or low speeds, a melted water pump housing, or brittle/cracked impeller vanes found during inspection.
Does this kit include the water pump housing?
Yes, this is a complete kit that includes the water pump housing (Part No. 438544) along with the impeller, gaskets, wear plate, and other necessary components for a full replacement.
Will this kit fit my 1988 Johnson 40 HP engine?
Based on the provided data, this kit is specified for 40 HP models starting from 1989. For models prior to 1989, you should verify the OEM part number of your original water pump to ensure compatibility, as there may be differences in the housing or components.
Is any special grease or lubricant required for installation?
Yes, it is highly recommended to use a marine-grade grease or a soapy water solution to lubricate the inside of the pump housing and the impeller vanes during installation. This prevents the impeller from damage during the first dry-start.
What is the main difference between this kit and the OEM version?
Our aftermarket kit is engineered to meet or exceed OEM specifications for fit, form, and function. This particular kit features an updated sealed bearing design that simplifies installation on older models. It offers comparable performance and longevity to the original part at a better value.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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