Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 433550)

Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 433550)

This complete lower unit gearcase seal kit is designed for Johnson/Evinrude 2-cylinder 40 HP, 48 HP, and 50 HP 2-stroke outboard motors from 1989-2005. Some sources also report compatibility with specific 25 HP models (D suffix) from 1990-1995.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including Johnson/Evinrude 433550/777551, Sierra 18-2694, GLM 87614, Mallory 9-74104, and EMP 26-07400.

• Installation: Direct replacement for a complete gearcase service.
• Compatibility: Fits a range of popular 2-cylinder Johnson/Evinrude outboards.
• Complete Kit: Includes all necessary seals, gaskets, o-rings, and drain screw for a full reseal.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

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.

Technical Specifications

Package Contents

This kit includes the following components for a complete lower unit service:

• 1 x Complete Lower Unit Seal Kit, which contains:
• 1 x Magnetic Drain Screw & Washer
• 1 x Prop Shaft Seal (Single seal with double lip design)
• 2 x Water Pump Gaskets
• 1 x Grommet
• Multiple x O-Rings (various types)
• Multiple x Oil Seals (various types)

Installation Guide

Professional installation is recommended. The following are general steps for replacement:

1. Drain Gear Oil: Position a drain pan under the lower unit and remove both the lower and upper drain/vent screws to drain the old gear oil completely.
2. Remove Lower Unit: Disconnect the shift linkage and remove the mounting bolts that attach the gearcase to the midsection. Carefully lower the unit.
3. Disassemble Gearcase: Begin disassembly by removing the water pump housing and impeller. Proceed to remove the bearing carrier and prop shaft assembly to access all seals.
4. Remove Old Seals: Carefully pry out the old prop shaft seals, driveshaft seals, and shift shaft seals. Remove all old o-rings and gaskets.
5. Clean and Inspect: Thoroughly clean all sealing surfaces, bores, and shafts. Inspect for any grooves, corrosion, or damage that could compromise the new seals.
6. Install New Seals: Using appropriate seal drivers, press the new seals into place. Ensure they are seated correctly and squarely. Install new o-rings and gaskets, applying a light coat of marine grease.
7. Reassemble Components: Reinstall the prop shaft assembly, bearing carrier, and water pump components according to your service manual's specifications.
8. Reinstall Lower Unit: Mount the lower unit back onto the engine, ensuring the driveshaft, water tube, and shift shaft are correctly aligned. Torque bolts to spec.
9. Refill with Oil: Fill the gearcase with fresh, high-quality marine gear lubricant through the bottom hole until it flows out the top hole. Reinstall and tighten both drain screws with new washers.

Troubleshooting & FAQ

Q: How can I confirm this seal kit fits my Johnson/Evinrude engine?
A: This kit is designed for Johnson/Evinrude 2-cylinder 40, 48, and 50 HP 2-stroke outboards from 1989-2005. It may also fit some 25 HP models with a "D" suffix from 1990-1995. The most reliable method is to cross-reference your original part number with 433550, 777551, or other alternatives listed in our cross-reference table before ordering.

Q: What are the common signs that my gearcase seals are failing?
A: The most common sign is milky or creamy-looking gear oil when you drain it, which indicates water contamination. Other signs include visible oil leaks around the propeller shaft or drain screws, or a distinct burning smell from the lower unit after operation.

Q: How often should I replace my lower unit seals?
A: It is best practice to replace your lower unit seals whenever you perform other major service, such as replacing the water pump impeller (typically every 2-3 years). They should be replaced immediately if you notice any signs of leaks or water intrusion to prevent catastrophic gear failure.

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?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.