Water Pump Impeller for Johnson Evinrude OMC BRP 375638
This high-quality aftermarket water pump impeller is engineered to fit Johnson/Evinrude outboard motors from 10 HP to 30 HP, covering models manufactured between 1949 and 1978. Designed for reliable cooling system performance, this impeller ensures consistent water flow to protect your engine from overheating during operation.
This replacement impeller directly crosses to OEM part numbers 375638, 389646, 775518, and aftermarket equivalent Sierra 18-3002. It features a durable 6-blade design with precision dimensions to match original equipment specifications.
- 6-blade impeller design for optimal water flow
- Direct replacement for multiple Johnson/Evinrude/OMC/BRP part numbers
- Fits 10 HP through 30 HP outboard motors (1949–1978)
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Johnson/Evinrude/OMC/BRP |
375638 |
| Johnson/Evinrude/OMC/BRP |
389646 |
| Johnson/Evinrude/OMC/BRP |
775518 |
| Sierra |
18-3002 |
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 |
Years |
| Evinrude Johnson |
10 HP |
1949-1957 |
| Evinrude Johnson |
15 HP |
1953-1965 |
| Evinrude Johnson |
18 HP |
1953-1965, 1968-1970 |
| Evinrude Johnson |
20 HP |
1966-1973 |
| Evinrude Johnson |
25 HP |
1969-1978 |
| Evinrude Johnson |
30 HP |
1970-1978 |
Technical Specifications
| Specification |
Value |
| Number of Blades |
6 |
| Depth / Height / Width |
13.08 mm |
| Outer / External Diameter |
69.37 mm |
| Internal Shaft Insert / Hub Diameter |
12.68 mm |
| Net Weight |
42 g |
Package Contents
Your package includes:
Installation Guide
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Disconnect the fuel line and remove the spark plug wires to ensure the engine cannot start during service.
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Remove the lower unit from the outboard motor according to your engine's service manual.
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Locate and remove the water pump housing to access the old impeller. Note the orientation of the impeller blades.
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Extract the old impeller carefully, checking for broken blades or debris that may indicate other pump damage.
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Clean the pump housing thoroughly and inspect the pump plate and liner for wear or scoring.
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Lubricate the new impeller with water pump grease or glycerin to ease installation and protect the rubber during initial startup.
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Insert the new impeller into the housing, ensuring the blades are oriented in the same direction as the original.
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Rotate the driveshaft by hand to verify the impeller turns freely without binding.
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Reassemble the water pump housing with a new gasket or O-ring as needed.
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Reinstall the lower unit onto the outboard, torquing all fasteners to manufacturer specifications.
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Reconnect the spark plug wires and fuel line. Start the engine in a test tank or on the water.
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Verify water flow from the telltale outlet within 15 seconds of startup to confirm proper pump operation.
Troubleshooting & FAQ
Q: How do I confirm this impeller fits my Johnson/Evinrude engine?
A: Cross-reference your engine's HP rating and year range with the compatibility table above. You can also verify the OEM part number (375638, 389646, or 775518) in your engine's parts diagram or service manual to ensure a proper match.
Q: How often should I replace my water pump impeller?
A: Most manufacturers recommend replacing the impeller annually or every 200–300 hours of operation, whichever comes first. If you operate in sandy or debris-filled water, or if the engine has run dry even briefly, inspect and replace the impeller more frequently.
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 cooling system, or a decrease in engine performance. If you notice any of these, inspect the impeller immediately to prevent serious engine damage.
Q: Can I use this impeller if my water pump housing is worn?
A: While this impeller will fit dimensionally, a worn or scored pump housing can cause the new impeller to fail prematurely. Always inspect the housing, wear plate, and liner during replacement, and replace any damaged components to ensure reliable cooling performance.
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?
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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.