Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP (Replaces 18-2691, 87611)
Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP (Replaces 18-2691, 87611) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP (Replaces...
Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP (Replaces 18-2691, 87611) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Lower Unit Seal Kit is designed for Johnson/Evinrude 85, 100, and 125 HP 2-stroke outboard models from 1971–1972 that are equipped with a large prop shaft. It provides the necessary seals, gaskets, and O-rings to service the lower gearcase, preventing water intrusion and gear oil leaks.
This kit is a direct interchange for several part numbers, including Sierra 18-2691, GLM 87611, and Mallory 9-74114, ensuring broad compatibility.
- Engineered for direct replacement installation.
- Specifically designed for models requiring seals for a large prop shaft.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Sierra | 18-2691 |
| GLM | 87611 |
| Mallory | 9-74114 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Johnson/Evinrude owners: Please verify your specific model and year against this list, paying close attention to the "Notes" column. This kit is only compatible with models featuring a large prop shaft.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | 85193A | 85 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 85193H | 85 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 85293R | 85 | 2-Stroke | 1972 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 85ESL71 | 85 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 85ESL72 | 85 | 2-Stroke | 1972 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 100193A | 100 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 100193C | 100 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 100293 | 100 | 2-Stroke | 1972 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 100ESL71 | 100 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 100ESL72 | 100 | 2-Stroke | 1972 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 125183C | 125 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 125283R | 125 | 2-Stroke | 1972 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 125ESL71 | 125 | 2-Stroke | 1971 | 18-2691 | Large Prop Shaft |
| Johnson/Evinrude | 125ESL72 | 125 | 2-Stroke | 1972 | 18-2691 | Large Prop Shaft |
Technical Specs
- Product Type
- Lower Unit/Gearcase Seal Kit
- Installation
- Direct replacement
- Other Technical Attributes
- For large prop shaft models
What’s in the Box
- Oil Seals
- O-rings
- Gaskets
Installation Notes
- Drain the old gearcase lubricant completely from the lower unit.
- Remove the propeller assembly and unbolt the lower unit from the outboard's leg.
- Disassemble the gearcase to access the driveshaft and prop shaft carriers. Carefully remove old seals, O-rings, and gaskets, taking care not to scratch sealing surfaces.
- Thoroughly clean all component surfaces of old adhesive, corrosion, and debris.
- Lightly lubricate the new seals and O-rings with marine grease before carefully pressing them into place using an appropriate seal driver.
- Reassemble the gearcase components, ensuring all bolts are tightened to the manufacturer's specified torque sequence.
- Before reinstalling the unit, perform both a vacuum and pressure test (typically 10-12 PSI) to confirm the new seals are seated correctly and have no leaks.
- Refill the lower unit with the correct grade and amount of marine gear lubricant. Reinstall the lower unit and check for leaks after the first use.
Troubleshooting & FAQ
What are the signs that my lower unit seals are failing?
Common symptoms include milky or foamy gear oil (indicating water intrusion), visible oil leaks dripping from the propeller shaft area, or excessive metal debris on the magnetic drain plug, often resulting from corrosion and wear caused by water contamination.
How do I confirm this kit is correct for my engine?
This kit fits specific Johnson/Evinrude 85, 100, and 125 HP models from 1971–1972 with a large prop shaft. Always match your full engine model number (e.g., 100ESL72) and year to the compatibility table. Do not order based on horsepower alone.
Is any special tool required for installation?
While basic service is possible with standard tools, professional installation is recommended. Specialized tools like a seal puller, bearing carrier retainer wrench, and a pressure/vacuum tester are often necessary to ensure seals are removed, installed, and tested correctly without damaging components.
How often should lower unit seals be replaced?
Seals should be replaced as a preventative measure every few seasons, or immediately if you notice any signs of leaks or water in the gear oil during your routine annual service. It is not based on hours but on inspection results.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
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.
Payment & Security
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