Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 433550, 18-2694, 87614, 9-74104)
Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 433550, 18-2694, 87614, 9-74104) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Repl...
Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 433550, 18-2694, 87614, 9-74104) is backordered and will ship as soon as it is back in stock.
Product Details
This Lower Unit Gearcase Seal Kit provides all necessary seals for servicing Johnson/Evinrude 2-cylinder 40 HP, 48 HP, and 50 HP 2-stroke outboard motors manufactured from 1989 to 2005. It ensures a reliable, leak-free repair of your engine's lower unit.
This kit is a direct replacement for Johnson/Evinrude part number 433550 and interchanges with Sierra 18-2694, GLM 87614, and Mallory 9-74104.
- Engineered as a direct-fit replacement for easy installation.
- Includes all essential seals for a comprehensive gearcase service.
- Covered by a 1-year warranty against manufacturing defects.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Johnson/Evinrude | 433550 |
| Sierra | 18-2694 |
| GLM | 87614 |
| Mallory | 9-74104 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This seal kit is designed for a range of 2-cylinder Johnson/Evinrude 2-stroke outboards produced between 1989 and 2005.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | Various | 25 HP | 2-Stroke | 1989–2005 | 433550 | Some retailers list 25 HP compatibility |
| Johnson/Evinrude | Various | 40 HP | 2-Stroke | 1989–2005 | 433550 | |
| Johnson/Evinrude | Various | 48 HP | 2-Stroke | 1989–2005 | 433550 | |
| Johnson/Evinrude | Various | 50 HP | 2-Stroke | 1989–2005 | 433550 |
Technical Specs
- Product Type
- Lower Unit Gearcase Seal Kit
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Warranty
- 1 Year
- Other Technical Attributes
- Complete kit for Johnson/Evinrude 2-cylinder 40-50 HP gearcase service
What’s in the Box
- 1x Complete Lower Unit Seal Kit (equivalent to 433550)
Installation Notes
- Drain the gearcase oil completely.
- Disassemble the lower unit to access the old seals, noting the orientation and order of components.
- Carefully remove all old seals, O-rings, and gaskets, taking care not to scratch sealing surfaces.
- Clean all housing bores and shaft surfaces thoroughly, removing any old sealant or corrosion.
- Lubricate the new seals and O-rings with a light coat of marine grease before installation.
- Install the new seals using an appropriate driver to ensure they are seated evenly and without damage.
- Reassemble the lower unit, torquing all fasteners to the manufacturer's specifications.
- Refill the gearcase with the recommended lubricant to the correct level and check for leaks.
Troubleshooting & FAQ
How do I know if my gearcase seals are failing?
Common signs include milky or discolored gear lube (indicating water intrusion), visible oil leaks around the propeller shaft or driveshaft, or a persistent burnt oil smell after operation.
Will this kit fit a 25 HP Johnson/Evinrude motor?
This kit is primarily specified for 40-50 HP models from 1989-2005. While some sources indicate compatibility with certain 25 HP models of the same era, please verify your specific OEM part number is 433550 before ordering to guarantee fitment.
Are any special tools required for installation?
Professional installation is recommended. Generally, this job requires standard mechanic's tools, a seal puller, and a seal driver or appropriately sized sockets to ensure seals are installed correctly without damage.
What is the recommended replacement interval for these seals?
There is no fixed interval, but it is good practice to inspect for leaks every season. Seals should be replaced whenever the lower unit is serviced for other reasons or immediately if signs of water intrusion or oil leakage are detected.
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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