Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP (Replaces 18-2691)
Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP (Replaces 18-2691) 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) is backordered and will ship as soon as it is back in stock.
Product Details
This Lower Unit Seal Kit – Fits Johnson/Evinrude 85/100/125 HP Large Prop Shaft 1971-1972 is an essential service part for maintaining the gearcase on specific 2-stroke Johnson and Evinrude 85, 100, and 125 HP engines from 1971–1972. It provides all the necessary seals and gaskets to prevent water intrusion and oil leaks, ensuring the longevity and performance of your outboard's lower unit.
This kit serves as a direct replacement for Sierra 18-2691, GLM 87611, and Mallory 9-74114, offering a reliable and cost-effective alternative to OEM parts.
- Installs as a direct replacement for the original components.
- Specifically designed for models equipped with the large prop shaft.
- Includes all necessary seals, gaskets, and O-rings for a complete overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number | Notes |
|---|---|---|
| Johnson/Evinrude (OEM) | 433550 | Original Equipment Manufacturer Reference |
| Sierra | 18-2691 | Aftermarket Equivalent |
| GLM | 87611 | Aftermarket Equivalent |
| Mallory | 9-74114 | Aftermarket Equivalent |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is designed exclusively for the Johnson and Evinrude models listed, covering 85, 100, and 125 HP variants manufactured in 1971 and 1972 with the large prop shaft.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | 85193A | 85 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 85193H | 85 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 85293R | 85 | 2-Stroke | 1972 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 85ESL71 | 85 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 85ESL72 | 85 | 2-Stroke | 1972 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 100193A | 100 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 100193C | 100 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 100293 | 100 | 2-Stroke | 1972 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 100ESL71 | 100 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 100ESL72 | 100 | 2-Stroke | 1972 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 125183C | 125 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 125283R | 125 | 2-Stroke | 1972 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 125ESL71 | 125 | 2-Stroke | 1971 | 433550 | Large Prop Shaft |
| Johnson/Evinrude | 125ESL72 | 125 | 2-Stroke | 1972 | 433550 | Large Prop Shaft |
Technical Specs
- Product Type
- Lower Unit Seal Kit
- Installation
- Direct replacement
- Other Technical Attributes
- Large prop shaft version
What’s in the Box
- 1 x Solenoid Cover Gasket (Replaces 0314876, 0777572, 18-2874)
- 2 x Oil Seal (Replaces 0330137, 0310600, 0321463, and others)
- 2 x Oil Seal (Replaces 0321466, 0313337, 0318223, and others)
- 2 x Drain/Fill Plug Washer (Replaces 0311598, 3852105, 18-4248)
- 4 x O-Ring Seal (Replaces 0317178, 0777520, 18-7109)
- 1 x O-Ring (Replaces 0313446, 0765593, 18-7127)
- 1 x O-Ring (Replaces 0354731, 0314728, 0777532, and others)
Installation Notes
- Place a drain pan under the lower unit and remove the upper and lower drain/fill screws to empty the gear lube.
- Disconnect the shift linkage and remove the bolts securing the lower unit to the engine. Carefully lower the gearcase.
- Remove the propeller, bearing carrier, and driveshaft components to access the old seals. Note the orientation of each seal before removal.
- Thoroughly clean all sealing surfaces, ensuring they are free of old adhesive, corrosion, or debris.
- Install the new seals and O-rings from the kit, using a proper seal driver or appropriately sized socket. Ensure they are seated correctly and uniformly.
- Reassemble the driveshaft, bearing carrier, and propeller, torquing all fasteners to the manufacturer's specifications.
- Reinstall the lower unit, reconnect the shift linkage, and refill with fresh marine gear lubricant before testing.
Troubleshooting & FAQ
What are the signs of a failing lower unit seal?
The most common sign is "milky" or cloudy gear lube, which indicates water has mixed with the oil. You might also notice gear oil leaking from the propeller shaft area or around the drain plugs. A pressure test of the gearcase can definitively diagnose a leak.
Is this kit compatible with other engine years or models?
No, this kit is specifically for the Johnson/Evinrude 85, 100, and 125 HP models from 1971–1972 that use the large propeller shaft. Using it on other models will result in leaks and potential gearcase damage. Always verify your engine's model and year.
How can I confirm I have the "large prop shaft" version?
The most reliable method is to check your engine's model number against the compatibility list or your service manual. Visually comparing your old seals to the pictures and part numbers in this listing can also help, but checking the model number is definitive.
How often should I replace my lower unit seals?
Seals should be inspected annually when you change your gear lube. It is recommended to replace them every 2-3 years as part of preventative maintenance, or immediately if you notice any signs of leaks or water intrusion.
Do I need special tools for this installation?
While basic hand tools are required, a seal puller and a proper seal driver set are highly recommended to prevent damage to the new seals or the gearcase housing during installation. A torque wrench is essential for correct reassembly.
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.
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