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

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

This water pump impeller repair kit is designed for a range of Johnson/Evinrude 2-Stroke 25-50 HP outboard engines. It is primarily compatible with 40-50 HP two-cylinder models manufactured between 1989 and 2005, and also fits specific 25, 28, 30, and 35 HP jet drive units.

This kit serves as a direct replacement for Johnson/Evinrude OEM part numbers 0438592/438592, 433548/433549/777805, and Sierra aftermarket part numbers 18-3454/18-3394.

• Includes a new pump housing for a complete overhaul.
• Engineered for the small gearcase configuration with a three-vane impeller.
• Installed in the lower unit/gearcase.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson Serial Number Guide.

Technical Specifications

Package Contents

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

Installation Guide

1. Safety First: Disconnect the battery and disable the ignition system.
2. Access the Lower Unit: Shift the outboard into neutral. Remove the bolts securing the lower unit (gearcase) to the engine leg and carefully lower it.
3. Remove the Old Pump: Unscrew the bolts holding the water pump housing. Lift the housing to expose the impeller and other components.
4. Inspect and Clean: Note the orientation of the old impeller vanes. Remove the old impeller, key, wear plate, and seals. Clean all surfaces of debris and old gasket material.
5. Install New Components: Place the new gasket and wear plate. Install the new impeller key into the driveshaft.
6. Install the New Impeller: Slide the new impeller onto the driveshaft, rotating the shaft clockwise to seat the vanes correctly within the new pump cup/housing.
7. Reassemble the Pump: Apply sealant to the new gasket, install the new housing, and tighten the bolts to the manufacturer's specified torque.
8. Reattach Lower Unit: Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are correctly aligned. Securely tighten all bolts.
9. Test the System: Reconnect the battery. With the outboard submerged in water, start the engine and verify a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How can I be sure this kit fits my Johnson/Evinrude engine?

A: The best way is to match your engine's model, horsepower, and year against the compatibility chart. This kit fits various 25-50 HP models, primarily from 1989-2005. Critically, ensure your engine requires OEM part number 438592, which this kit replaces.

Q: What are the signs that my water pump impeller needs to be replaced?

A: Common signs include the engine overheating at idle or low speeds, a weak or inconsistent water stream from the "tell-tale" exhaust port, or finding a brittle, cracked, or deformed impeller during a routine inspection.

Q: How often should I replace my water pump impeller?

A: As a crucial part of preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1-2 years. Replacement frequency should increase with heavy use, especially in saltwater or cloudy/sandy water.

Q: Does this kit include the housing?

A: Yes, this is a complete water pump repair kit that includes the pump housing, impeller, wear plate, gaskets, seals, and installation bolts required for a full replacement.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.