Water Pump Impeller – Fits Johnson/Evinrude 35-55 HP Outboards (Replaces 377230, 777213)
This aftermarket water pump impeller is designed for Johnson/Evinrude 35-55 HP 2-Stroke outboard motors from 1958 to 1978. It serves as a direct replacement for the original component to ensure your engine maintains proper cooling and avoids overheating.
It directly replaces the following OEM and aftermarket part numbers: Johnson/Evinrude 377230, 777213, 777821; Sierra 18-3083; and Mallory 9-45209.
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Material: Constructed from durable neoprene rubber with a brass hub for saltwater resistance.
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Function: Restores pump performance to prevent engine overheating.
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Installation: Direct replacement fit in the water pump housing.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Johnson/Evinrude |
377230 |
| Johnson/Evinrude |
777213 |
| Johnson/Evinrude |
777821 |
| Sierra |
18-3083 |
| Mallory |
9-45209 |
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/Evinrude Serial Number Guide.
| Brand |
Model |
Rated HP |
Stroke |
Years |
OEM Part No. |
Notes |
| Johnson |
Various |
35 |
2-Stroke |
1958-1959 |
377230 |
|
| Johnson |
Various |
40 |
2-Stroke |
1960-1970 |
377230 |
|
| Johnson |
Various |
50 |
2-Stroke |
1971-1978 |
377230 |
|
| Johnson |
Various |
55 |
2-Stroke |
1971-1978 |
377230 |
|
| Evinrude |
Various |
35 |
2-Stroke |
1958-1959 |
377230 |
|
| Evinrude |
Various |
40 |
2-Stroke |
1960-1970 |
377230 |
|
| Evinrude |
Various |
50 |
2-Stroke |
1971-1978 |
377230 |
|
| Evinrude |
Various |
55 |
2-Stroke |
1971-1978 |
377230 |
|
Technical Specifications
| Specification |
Value |
| Product Type |
Water Pump Impeller |
| Installation |
Direct replacement in water pump housing |
| Material |
Neoprene rubber with brass hub |
| Dimensions |
External Diameter: 69.81 mm (2 3/4"), Internal Shaft Insert Diameter: 15.91 mm (5/8"), Height: 21.79 mm (55/64") |
| Color |
Black with brass center |
| Number of Blades |
6 |
| Durability |
Resistant to salt water immersion |
| Application |
OEM replacement for cooling system water pump |
Package Contents
- 1 x Water Pump Impeller (Replaces 377230/777213)
Installation Guide
Professional installation is recommended. The general steps are as follows:
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Safety First: Disconnect the battery and ensure the engine is off and cool.
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Access the Lower Unit: Drain the gearcase oil, then unbolt and carefully remove the lower unit (gearcase) from the outboard motor.
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Open Water Pump Housing: Locate the water pump assembly on top of the lower unit. Remove the bolts securing the housing cover.
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Remove Old Impeller: Slide the old impeller off the drive shaft. Note the rotational direction of the old impeller blades if possible.
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Install New Impeller: Lightly lubricate the new impeller and housing. Slide the new impeller onto the shaft, rotating it in the correct direction to seat the blades.
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Reassemble: Reinstall the water pump housing, ensuring all seals and gaskets are correctly placed.
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Reattach Lower Unit: Securely bolt the lower unit back onto the outboard and refill the gearcase oil.
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Test Operation: Reconnect the battery and run the engine with a water supply to check for proper water flow and temperature.
Troubleshooting & FAQ
Q: How do I confirm this impeller fits my engine?
A: The best way is to check your OEM part number. This impeller replaces Johnson/Evinrude part numbers 377230, 777213, and 777821. You can also use the compatibility table on this page to verify your engine's HP, model, and year range.
Q: What are the signs of a bad or failing water pump impeller?
A: Common symptoms include the engine overheating, an intermittent or weak water stream from the "tell-tale" outlet, or an audible alarm from your engine's warning system.
Q: How often should I replace the water pump impeller?
A: As a general maintenance rule, it’s recommended to inspect and/or replace the impeller annually or every 100 hours of operation, whichever comes first. This interval can change based on usage patterns and water conditions.
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.