Lower Unit Seal Kit for Johnson/Evinrude 85/100/125 HP Large Propeller Shaft, 1971–1972 — Replaces Sierra 18-2691

Product Details

This lower unit seal kit is designed for specific 2-stroke Johnson and Evinrude 85, 100, and 125 HP outboards from 1971–1972 equipped with the large propeller shaft. The kit provides replacement seals, gaskets, and O-rings used to help protect the gearcase from water intrusion and lubricant leaks during lower-unit service.

It is listed as a replacement for Sierra 18-2691, GLM 87611, and Mallory 9-74114. Confirm the engine model, year, and large-propeller-shaft configuration before ordering.

• Replacement lower-unit seal kit for specified Johnson/Evinrude applications.
• Intended for models using the large propeller shaft.
• Includes multiple oil seals, O-rings, and drain/fill plug washers for lower-unit service.
• Aftermarket replacement component; not an OEM-branded part.

Part Number Matrix

Use the references below to compare this kit with listed OEM and aftermarket numbers. Number references should be matched with the correct engine application and component requirements.

Engine & Model Compatibility

This kit is intended for the Johnson and Evinrude model applications listed below. The listed engines are 2-stroke models from 1971 or 1972 using the large propeller shaft.

Technical Specifications

Product Type

Lower unit seal kit

Application

Johnson/Evinrude 85, 100, and 125 HP 2-stroke outboards

Application Years

1971–1972

Propeller Shaft Configuration

Large propeller shaft

Installation

Replacement lower-unit service part

Product Status

Aftermarket replacement; not OEM-branded

What's in the Box

• 1 × Solenoid cover gasket; replaces 0314876, 0777572, and 18-2874.
• 2 × Oil seals; replaces 0330137, 0310600, 0321463, and related applications.
• 2 × Oil seals; replaces 0321466, 0313337, 0318223, and related applications.
• 2 × Drain/fill plug washers; replaces 0311598, 3852105, and 18-4248.
• 4 × O-ring seals; replaces 0317178, 0777520, and 18-7109.
• 1 × O-ring; replaces 0313446, 0765593, and 18-7127.
• 1 × O-ring; replaces 0354731, 0314728, 0777532, and related applications.

Installation Notes

1. Place a drain pan beneath the lower unit and remove the upper and lower drain/fill screws to drain the gear lubricant.
2. Disconnect the shift linkage and remove the fasteners securing the lower unit to the engine. Carefully lower the gearcase.
3. Remove the propeller and the required bearing-carrier and driveshaft components to access the seals. Record the orientation of each seal before removal.
4. Clean all sealing surfaces thoroughly and remove old sealant, corrosion, lubricant residue, and debris.
5. Install the replacement seals and O-rings with a suitable seal driver or correctly sized socket. Seat each part evenly and in the correct orientation.
6. Reassemble the driveshaft, bearing carrier, and propeller according to the applicable service information. Tighten fasteners to the manufacturer's specifications.
7. Reinstall the lower unit, reconnect the shift linkage, refill the gearcase with the correct marine gear lubricant, and check for leaks before normal operation.

Troubleshooting & FAQ

Safety & Important Information

• Verify the engine brand, complete model number, year, horsepower, stroke, and large-propeller-shaft configuration before ordering.
• Reference numbers and horsepower alone do not establish compatibility for every engine configuration.
• Follow the applicable service manual for disassembly, seal orientation, lubricant specifications, and torque values.
• Professional installation is recommended when specialized lower-unit tools or service procedures are required.

About Sea Sierra

• Marine Replacement Parts — Replacement components for common outboard service applications.
• Application-Focused Listings — Product references and fitment details are provided to help with part identification.
• Service Support — Always compare the product details with the engine's model information and service requirements before installation.