Oil Seal – Fits Johnson/Evinrude/OMC 9.9-15 HP (Replaces 321481, 0321481)
Oil Seal – Fits Johnson/Evinrude/OMC 9.9-15 HP (Replaces 321481, 0321481) 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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Oil Seal – Fits Johnson/Evinrude/OMC 9.9-15 HP (Replaces 321481, 03...
Oil Seal – Fits Johnson/Evinrude/OMC 9.9-15 HP (Replaces 321481, 0321481) is backordered and will ship as soon as it is back in stock.
Product Details
This high-quality Oil Seal – Fits Johnson/Evinrude/OMC 9.9-15 HP (Replaces 321481, 0321481) is engineered for a precise fit on a range of Johnson and Evinrude outboard motors. It is primarily designed for 9.9 HP and 15 HP models from 1974–1975, and also fits some 40 HP applications from the same years.
This component serves as a direct cross-reference for several OEM and aftermarket part numbers, including Sierra 18-2029, GLM 86180, and OMC/BRP 777525, ensuring broad compatibility and a reliable seal.
- Installs on the propeller shaft within the lower gearcase bearing housing.
- Engineered to prevent gear lube leaks and water intrusion into the gearcase.
- Includes one high-grade oil seal per package.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| OMC / BRP | 321481 / 0321481 / 777525 |
| Sierra | 18-2029 |
| GLM | 86180 |
| Mallory Marine | 9-76218 |
| SEI Marine | 94-361-01 |
| Barr Marine | OMC47-321481 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Johnson | 10E74G, 10E74S, 10EL74G, 10ELT4S, 10R74G, 10R74S, 10RL74G, 10RL74S | 9.9 | 1974 | 321481/0321481 | |
| Johnson | 10E75C, 10EL75C, 10R75C, 10RL75C | 9.9 | 1975 | 321481/0321481 | |
| Johnson | 15E74G, 15E74S, 15EL74G, 15EL74S, 15R74G, 15R74S, 15RL74G, 15RL74S | 15 | 1974 | 321481/0321481 | |
| Johnson | 15E75C, 15EL75C, 15R75C, 15RL75C | 15 | 1975 | 321481/0321481 | |
| Johnson | 40E74S, 40EL74S, 40R74S, 40RL74S | 40 | 1974 | 321481/0321481 | |
| Johnson | 40E75C, 40EL75C, 40R75C, 40RL75C | 40 | 1975 | 321481/0321481 | |
| Evinrude | 10424G, 10424S, 10425G, 10425S, 10454G, 10454S, 10455G, 10455S | 9.9 | 1974 | 321481/0321481 | |
| Evinrude | 10524C, 10525C, 10554C, 10555C | 9.9 | 1975 | 321481/0321481 | |
| Evinrude | 15404G, 15404S, 15405G, 15405S, 15454G, 15454S, 15455G, 15455S | 15 | 1974 | 321481/0321481 | |
| Evinrude | 15504C, 15505C, 15554C, 15555C | 15 | 1975 | 321481/0321481 | |
| Evinrude | 40404S, 40405S, 40454S, 40455S | 40 | 1974 | 321481/0321481 | |
| Evinrude | 40504C, 40505C, 40554C, 40555C | 40 | 1975 | 321481/0321481 |
Technical Specs
- Product Type
- Oil Seal / Shaft Seal
- Installation Location
- Lower Gearcase / Bearing Housing to Propeller Shaft
- Inside Diameter
- 0.687 in. (17.45 mm)
- Outside Diameter
- 1.250 in. (31.75 mm)
- Height/Width
- 0.250 in. (6.35 mm)
- Compatible Shaft Size
- 0.687 in.
- Weight
- 0.02 lbs (0.009 kg)
What’s in the Box
- 1 x Oil Seal (Replaces OMC 321481 / 0321481)
Installation Notes
- Drain the lower unit gear lube completely into a suitable container.
- Remove the propeller, thrust washer, and any related hardware.
- Unbolt and carefully extract the bearing housing carrier from the gearcase.
- Pry out the old oil seal from the housing, taking care not to scratch the housing bore. Note the orientation of the seal before removal.
- Thoroughly clean the seal bore in the housing to remove any old sealant or corrosion.
- Lubricate the outer diameter of the new seal with a thin film of sealant or grease.
- Using a seal driver or socket that matches the seal's outer diameter, press the new seal in squarely until it is fully seated.
- Lightly grease the inner lip of the new seal to prevent damage on initial startup.
- Reinstall the bearing housing into the gearcase, torquing fasteners to the manufacturer’s specifications.
- Reinstall the propeller and refill the lower unit with the correct gear lube.
Troubleshooting & FAQ
How do I know if this seal is the right one for my engine?
The best way to confirm fitment is to match your original part number to the ones listed in our Part Number Matrix. You should also verify that your engine's model and year are included in the Engine & Model Compatibility table. Visually comparing the dimensions (I.D., O.D., Width) with your old seal is a recommended final check.
What are the signs of a failed propeller shaft seal?
The most common symptom is milky, gray, or creamy-looking gear lube when you drain it, which indicates water has contaminated the oil. You may also notice gear lube leaking out from around the propeller area or a recurring need to top off the gearcase oil.
Can I replace this seal myself?
This task is manageable for those with mechanical experience and the right tools, such as a seal puller and driver set. However, due to the need for precise installation to prevent leaks, we recommend professional installation if you are not fully comfortable with the process.
How often should this seal be replaced?
It's good practice to inspect the seals whenever you service the lower unit or change the propeller. We recommend replacing them as a preventative measure every few seasons, or immediately if you see any signs of gear lube leakage or water intrusion.
Should I replace any other seals at the same time?
Yes. When the lower unit is disassembled to this extent, it is highly recommended to also replace the other seals in the bearing carrier and any driveshaft or shift shaft seals that are accessible. This ensures a comprehensive and long-lasting repair.
Is there a 'break-in' period for a new seal?
There is no formal break-in period required. However, after installation, it's wise to run the engine briefly (in water) and then re-check for any signs of leakage around the propeller shaft to ensure the seal is seated and functioning correctly.
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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