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) 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 Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Repl...
Lower Unit Gearcase Seal Kit – Fits Johnson/Evinrude 40-50 HP (Replaces 433550) is backordered and will ship as soon as it is back in stock.
Product Details
This Lower Unit Gearcase Seal Kit is designed for Johnson/Evinrude 2-cylinder 40 HP, 48 HP, and 50 HP 2-stroke outboard motors manufactured from 1989 to 2005. It also provides coverage for select 25 HP models with a 'D' suffix from 1990–1995.
It serves as a direct replacement for Johnson/Evinrude part numbers 433550 and 777551, as well as aftermarket equivalents including Sierra 18-2694, GLM 87614, Mallory 9-74104, and EMP 26-07400.
- Direct replacement for a hassle-free installation.
- Includes a complete set of seals, gaskets, and o-rings for a full gearcase service.
- Engineered for use in standard gasoline outboard environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Johnson/Evinrude | 433550 |
| Johnson/Evinrude | 777551 |
| Sierra | 18-2694 |
| GLM | 87614 |
| Mallory | 9-74104 |
| EMP | 26-07400 |
| JLM Marine | 433550 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit fits a range of Johnson/Evinrude 2-stroke outboards. Please verify your specific model and year before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | Various | 25 HP | 2-Stroke | 1990–1995 | 433550 | D suffix only; compatibility reported by some retailers |
| Johnson/Evinrude | Various | 40 HP | 2-Stroke | 1989–2005 | 433550 | |
| Johnson/Evinrude | Various | 48 HP | 2-Stroke | 1989–1996 | 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
- Weight
- 0.14 kg (0.31 lb)
- Warranty
- 1 Year (JLM Marine), 30 days (Southcentral Outboards)
- Other Technical Attributes
- Complete kit for Johnson/Evinrude 2-cylinder 40-50 HP gearcase service
What’s in the Box
- 1 x Complete Lower Unit Seal Kit, which includes:
- 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 O-Rings (various types)
- Multiple Oil Seals (various types)
Installation Notes
- Drain the existing gearcase oil by removing the drain and vent screws.
- Remove the propeller assembly and disconnect the lower unit (gearcase) from the upper driveshaft housing.
- Carefully disassemble the gearcase components, including the bearing carrier and driveshaft, laying them out in order.
- Remove all old seals, o-rings, and gaskets from their respective locations. Thoroughly clean all surfaces of old sealant and debris.
- Install the new seals, o-rings, and gaskets from the kit. Ensure seals are properly seated and oriented. Lightly lubricate seals with marine grease before installation.
- Reassemble all gearcase components in reverse order, torquing bolts to manufacturer specifications.
- Reattach the lower unit to the engine.
- Refill the gearcase with the correct type and amount of lower unit lubricant before operating. Check for leaks at the drain screw.
Troubleshooting & FAQ
How do I know if this seal kit fits my specific Johnson/Evinrude engine?
This kit is designed for 2-cylinder 40, 48, and 50 HP models from 1989–2005. It may also fit 25 HP models from 1990-1995 with a 'D' suffix. The best way to confirm is by cross-referencing your engine's original gearcase part number with the numbers listed in our Part Number Matrix.
What are the signs my old gearcase seals are failing?
Common symptoms include milky or watery gear oil (indicating water intrusion), visible oil leaks around the propeller shaft or drain screws, or a metallic sheen in the oil from bearing wear.
Does this kit include both driveshaft and propeller shaft seals?
Yes, this is a comprehensive kit that includes all necessary seals for a full lower unit service, including the primary propeller shaft seal and driveshaft seals.
What is the difference between this kit and the OEM version?
This is an aftermarket kit designed to meet or exceed original equipment manufacturer (OEM) specifications for fit, function, and material quality. It provides comparable performance at a better value.
How often should lower unit seals be replaced?
There is no fixed interval, but seals should be inspected annually during your regular lower unit service. They should be replaced immediately if you find any signs of water in the gear lube or visible leaks.
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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