Water Pump Impeller – Fits Johnson/Evinrude 9.5HP & 10HP (Replaces 377178, 775519)

Product Details

This is a direct replacement Water Pump Impeller – Fits Johnson/Evinrude 9.5HP & 10HP (Replaces 377178, 775519). It is designed for specific Johnson/Evinrude 2-stroke outboard models, including 9.5HP engines manufactured from 1964–1973 and 10HP engines from 1958–1963, ensuring reliable cooling performance.

This impeller is a direct interchange for multiple part numbers, including Sierra 18-3003, Mallory 9-45218, GLM 89670, SEI Marine 96-361-03BE, and CEF 500349.

• Engineered for direct-fit installation in the original water pump housing.
• Constructed from durable rubber with a metallic insert for longevity.
• Features a 6-blade design to restore proper water circulation.

Part Number Matrix

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

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Johnson/Evinrude models, please check your specific model number, horsepower rating, and year range to ensure this part is a correct match.

Technical Specs

Product Type

Water Pump Impeller

Installation

Direct replacement

Material

Rubber with copper/brass insert

Number of Blades

6

External Impeller Diameter

69mm (2.72in)

Internal Shaft Insert Diameter

14.1mm (0.56in)

Color

Black/Gold (metallic center)

Housing Compatibility

Original Johnson/Evinrude water pump housing

Other Technical Attributes

Key slot design for shaft engagement

What’s in the Box

• 1 x Water Pump Impeller (377178/775519)

Installation Notes

1. Disconnect the battery and remove the engine cover.
2. Drain the lower unit gear lube.
3. Remove the bolts securing the lower unit (gearcase) to the engine's midsection.
4. Carefully lower and remove the gearcase assembly.
5. Locate and unbolt the water pump housing cover.
6. Slide the old impeller off the drive shaft, noting the keyway position.
7. Clean any debris from the housing and inspect components for wear.
8. Lubricate the new impeller and housing interior with a marine-grade lubricant.
9. Install the new impeller onto the shaft, aligning the keyway. Rotate the driveshaft clockwise while pushing down to seat the blades correctly.
10. Reinstall the housing cover, replace gaskets/seals as needed, and tighten bolts to spec.
11. Re-attach the lower unit to the engine, refilling gear lube once secured.
12. Reconnect the battery and test the engine in water, confirming a steady water stream from the tell-tale outlet.

Troubleshooting & FAQ

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.