Water Pump Impeller Repair Kit with Housing – Fits Johnson/Evinrude 25-50 HP (Replaces 438592)

$35.77

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Water Pump Impeller Repair Kit with Housing – Fits Johnson/Evinrude 25-50 HP (Replaces 438592) is backordered and will ship as soon as it is back in stock.

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Product Details

This complete Water Pump Impeller Repair Kit with Housing is designed for Johnson and Evinrude 2-stroke outboard engines. It provides a comprehensive solution for servicing the cooling system on compatible 25-50 HP engines, primarily targeting 40-50 HP two-cylinder models manufactured from 1989 to 2005. The kit also covers specific 25, 28, 30, and 35 HP jet drive units.

It serves as a direct replacement for Johnson/Evinrude OEM part number 438592 and Sierra aftermarket number 18-3454, among other cross-references, ensuring broad interchange compatibility.

Installation Location: Lower Unit/Gearcase
Key Component: Includes a three-vane neoprene impeller suitable for small gearcase configurations.
Complete Kit: Contains the pump housing, impeller, wear plate, gaskets, seals, and stainless steel bolts for a full service.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Johnson/Evinrude	0438592 / 438592
Johnson/Evinrude	433548 / 433549 / 777805
Sierra	18-3454 / 18-3394

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This kit is verified for a range of Johnson and Evinrude 2-stroke models. Please check your specific horsepower, year, and application type (Gearcase or Jet Drive) to ensure correct fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Evinrude	40	40	2-Stroke	1997–1998	438592	Gearcase
Evinrude	50	50	2-Stroke	1998	438592	Gearcase
Johnson	35	35	2-Stroke	1997	438592	Gearcase
Johnson	40	40	2-Stroke	1997–2005	438592	Gearcase
Johnson	50	50	2-Stroke	1997–2001, 2004	438592	Gearcase
Evinrude	28 Jet	28	2-Stroke	1997–1998	438592	Jet Drive Unit
Evinrude	35 Jet	35	2-Stroke	1997	438592	Jet Drive Unit
Evinrude	40 Jet	40	2-Stroke	1997	438592	Jet Drive Unit
Evinrude	50 Jet	50	2-Stroke	1997	438592	Jet Drive Unit
Johnson	25 Jet	25	2-Stroke	2000	438592	Jet Drive Unit
Johnson	28 Jet	28	2-Stroke	1997–1998	438592	Jet Drive Unit
Johnson	30 Jet	30	2-Stroke	1999–2001	438592	Jet Drive Unit
Johnson	35 Jet	35	2-Stroke	1997	438592	Jet Drive Unit
Johnson	40 Jet	40	2-Stroke	1997	438592	Jet Drive Unit
Johnson	50 Jet	50	2-Stroke	1997	438592	Jet Drive Unit
Johnson	30	30	2-Stroke	2001	438592	Steering Handle

Technical Specs

Product Type: Water Pump Repair Kit with Housing
Installation: Lower Unit/Gearcase
Weight: 0.51 kg (1.12 lbs)
Other Technical Attributes: For small gearcase configuration with three-vane impeller
Warranty: 12-Month (Varies by manufacturer)

What’s in the Box

1 x Neoprene Impeller, 3-vane (432941/437059/765350)
1 x Wear Plate (321940)
1 x Insert Cup/Water Pump Cup (340619)
1 x Water Pump Gasket (336530)
1 x Key/Impeller Key (334897)
1 x O-Ring (Possibly multiple)
1 x Water Seal/Oil Seal (315748)
1 x Pump Housing
1 x Grommet (333758)
4 x Installation Bolts, Stainless Steel (331979)

Installation Notes

Disconnect the negative battery cable and remove the engine cover. Disconnect the shift linkage.
Place a drain pan under the gearcase and remove the retaining bolts to lower the unit from the engine.
Unbolt and carefully lift the old water pump housing. Note the orientation of the old impeller vanes.
Remove the old impeller, key, wear plate, gaskets, and seals. Thoroughly clean all mounting surfaces.
Install the new gasket and wear plate. Insert the new impeller key and slide the new impeller on, turning the driveshaft clockwise to seat the vanes correctly.
Apply a thin layer of marine grease to the inside of the new insert cup and install it into the housing.
Install the new gaskets/seals on the housing and secure it with the provided stainless steel bolts, tightening to manufacturer torque specs.
Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are correctly aligned. Reconnect the shift linkage and test engine operation with a proper water supply.

Troubleshooting & FAQ

How do I confirm this kit fits my specific engine model?

First, check the compatibility table on this page to see if your model and year are listed. Second, verify that your engine's current part is an equivalent to OEM part number 438592. This kit is primarily for two-cylinder 40-50 HP models from 1989–2005 and specific jet drives.

What are the signs of a failing water pump impeller?

Common signs of a worn or failed impeller include the engine overheating at idle or low speeds, a weak or intermittent water stream from the "telltale" outlet, or finding brittle, cracked, or broken vanes during a visual inspection.

How often should the water pump impeller be replaced?

As a preventative maintenance best practice, it is recommended to inspect the impeller annually and replace it every 1 to 2 years, or every 100-200 hours of engine use. Replacement intervals should be shorter if operating frequently in saltwater, silty, or sandy conditions.

What is the main difference between this kit and an OEM version?

This kit is a high-quality aftermarket alternative, designed to meet or exceed original equipment specifications for fit, form, and function. It provides a cost-effective solution that includes all the necessary components for a complete water pump service, including the housing.

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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