Water Pump Impeller – Fits Johnson/Evinrude 40HP (Replaces 390286, 0390286, 777835, 0777835)

Product Details

This aftermarket Water Pump Impeller is designed for reliable performance in Evinrude/Johnson Outboard 40HP 2-Stroke engines manufactured between 1983 and 1986. It serves as a direct-fit replacement, ensuring your engine's cooling system functions efficiently for optimal engine health and longevity.

It is a direct replacement for Johnson/Evinrude part numbers 390286, 0390286, 777835, and 0777835, and interchanges with Sierra 18-3366, CEF 500353, Mallory Marine 9-45212, and others.

• Installs as a direct replacement component.
• Constructed from durable neoprene rubber for a long service life.
• Available as an impeller only or as a kit with the key pin included.

Part Number Matrix

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

Engine & Model Compatibility

Confirm your engine model and year in the tables below.

This impeller is compatible with various 40 HP 2-Stroke Evinrude outboard models from the mid-1980s.

This impeller is also compatible with various 40 HP 2-Stroke Johnson outboard models from the same period.

Technical Specs

Product Type

Water Pump Impeller

Installation

Direct replacement

Material

Neoprene rubber

Number of Blades

6

Hub/Shaft Size

0.689 inch (17.5 mm)

Height/Thickness

0.748 inch (19 mm)

External Diameter

2.004 inch (50.9 mm)

Key/Pin Compatibility

0305350, 0308928, 0777849, 308924, 308928

Other Technical Attributes

Some variants include the key pin (e.g., 17IO016K), while others are the impeller only (e.g., 17IO016).

What’s in the Box

Package contents vary based on the specific part number selected. Please verify before ordering.

• Part numbers ending in "K" (e.g., Soxa Marine 17IO016K):
  • 1 x Water Pump Impeller (replaces 390286)
  • 1 x Impeller Key Pin
• Part numbers without a "K" suffix (e.g., Soxa Marine 17IO016):
  • 1 x Water Pump Impeller (replaces 390286)

Installation Notes

1. Disconnect the battery and remove the engine cover.
2. Shift the outboard into neutral.
3. Remove the lower unit (gearcase) by unbolting it from the engine's midsection.
4. Locate and unbolt the water pump housing cover.
5. Carefully remove the old impeller, noting the direction of the blades.
6. Clean the housing and inspect it for wear, cracks, or corrosion. Replace if damaged.
7. Install the new impeller with a slight clockwise rotation to bend the blades correctly. Ensure the key pin is properly seated.
8. Reassemble the water pump housing, ensuring a tight seal.
9. Reattach the lower unit to the midsection and secure all bolts.
10. Reconnect the battery, start the engine in water, and verify water is exiting the "telltale" outlet.

Troubleshooting & FAQ

Safety & Important Info

• Verify images and specifications against 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.