Water Pump Impeller – Fits Johnson/Evinrude 40–75 HP Outboard Motors
This high-quality water pump impeller is designed for Johnson/Evinrude outboard motors rated 40 HP, 50 HP, 55 HP, 60 HP, 65 HP, 70 HP, and 75 HP. It ensures reliable cooling system performance and protects your engine from overheating during operation.
This impeller directly replaces OEM part numbers 396725, 432594, and 437080, as well as aftermarket equivalents from Sierra (18-3053) and CEF (500303).
- Includes rubber impeller with key/pin for complete installation
- Precision-molded for exact fitment and durability
- Essential maintenance component for optimal water pump function
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
Notes |
| Johnson/Evinrude (OEM) |
396725 |
Original Equipment Manufacturer |
| Johnson/Evinrude (OEM) |
432594 |
Original Equipment Manufacturer |
| Johnson/Evinrude (OEM) |
437080 |
Original Equipment Manufacturer |
| Johnson/Evinrude (OEM) |
0396725 |
Alternate OEM format |
| Johnson/Evinrude (OEM) |
432952 |
Related OEM number |
| Sierra |
18-3053 |
Aftermarket replacement |
| CEF |
500303 |
Aftermarket replacement |
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.
| Brand |
Rated HP |
Notes |
| Evinrude |
40 HP |
Outboard motor engine |
| Evinrude |
50 HP |
Outboard motor engine |
| Evinrude |
55 HP |
Outboard motor engine |
| Evinrude |
60 HP |
Outboard motor engine |
| Evinrude |
65 HP |
Outboard motor engine |
| Evinrude |
70 HP |
Outboard motor engine |
| Evinrude |
75 HP |
Outboard motor engine |
| Johnson |
40 HP |
Outboard motor engine |
| Johnson |
50 HP |
Outboard motor engine |
| Johnson |
55 HP |
Outboard motor engine |
| Johnson |
60 HP |
Outboard motor engine |
| Johnson |
65 HP |
Outboard motor engine |
| Johnson |
70 HP |
Outboard motor engine |
| Johnson |
75 HP |
Outboard motor engine |
Technical Specifications
| Specification |
Value |
| OEM Part Numbers |
396725, 432594, 437080, 0396725, 432952 |
| Aftermarket Equivalents |
Sierra 18-3053, CEF 500303 |
| Application |
Water pump cooling system |
| Material |
Rubber (marine-grade) |
| Compatible Brands |
Johnson, Evinrude |
| Horsepower Range |
40 HP, 50 HP, 55 HP, 60 HP, 65 HP, 70 HP, 75 HP |
Package Contents
- Outboard Rubber Impeller with Key/Pin
Installation Guide
- Disconnect the fuel line and remove the engine cover to access the lower unit. Ensure the engine is completely cool before beginning work.
- Remove the propeller and drain the gear oil from the lower unit. Set aside the hardware for reassembly.
- Unbolt and separate the lower unit from the mid-section of the outboard motor. Support the lower unit carefully to avoid damage.
- Locate the water pump housing on the lower unit. Remove the bolts securing the pump housing and lift it off to expose the impeller.
- Carefully remove the old impeller from the shaft. Inspect the housing and wear plate for cracks, scoring, or excessive wear.
- Clean the pump housing thoroughly, removing any debris or old gasket material. Replace the wear plate if it shows significant damage.
- Lubricate the new impeller with glycerin or soapy water (never petroleum-based products). Insert the key/pin into the impeller hub slot.
- Install the impeller onto the driveshaft, rotating the blades in the correct direction per your service manual. Ensure the key engages properly with the shaft.
- Apply a thin coat of marine grease to new gaskets and position them on the pump housing. Reinstall the housing, tightening bolts evenly in a crisscross pattern.
- Reattach the lower unit to the mid-section, ensuring proper alignment. Torque all mounting bolts to manufacturer specifications.
- Refill the lower unit with fresh gear oil and reinstall the propeller. Double-check all fasteners are secure.
- Run the engine in a test tank or on the water, checking for steady water flow from the telltale (pee hole). Monitor engine temperature during initial operation.
Troubleshooting & FAQ
Q: How do I confirm this impeller fits my specific Johnson or Evinrude outboard?
A: Verify your engine's horsepower matches the 40–75 HP range listed in the compatibility table. Cross-reference your original part number (396725, 432594, or 437080) with the numbers shown above, or consult your engine's service manual.
Q: How often should I replace my water pump impeller?
A: Most manufacturers recommend replacing the impeller every 2–3 years or 200–300 hours of operation, whichever comes first. If you notice overheating, weak water flow from the telltale, or the engine has been run dry, replace the impeller immediately.
Q: What are the signs that my impeller is failing?
A: Common symptoms include reduced or no water flow from the telltale outlet, engine overheating, steam from the engine, or an audible high-temperature alarm. Inspect the impeller if any of these occur.
Q: Can I use petroleum-based lubricants when installing this impeller?
A: No, petroleum-based products will damage the rubber. Always use glycerin, soapy water, or a water-based lubricant specifically designed for marine impellers.
Q: What is the difference between this aftermarket impeller and the OEM version?
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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.