Propeller Shaft Oil Seal 3863090 – Fits OMC Cobra SX Stern Drives (Replaces 3858303, 3853474, 3850482)

Propeller Shaft Oil Seal 3863090 – Fits OMC Cobra SX & Volvo Penta SX Stern Drives

This propeller shaft oil seal is engineered for OMC Cobra SX stern drives (1994 and newer) and compatible Volvo Penta SX drives. It provides a critical seal for the propeller shaft, preventing oil leakage from the lower gearcase and ensuring protection of the internal gearing.

This is a direct replacement for multiple OEM and aftermarket part numbers, designed to meet or exceed original specifications for fit and function. It installs in the propeller shaft carrier assembly within the lower unit gearcase.

• Installation Location: Lower Unit Gearcase, Propeller Shaft Carrier
• Function: Seals propeller shaft to prevent gearcase oil leakage
• Construction: Durable rubber housing with a reinforced metal casing

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

OMC Cobra SX Models

Volvo Penta Models

Technical Specifications

Package Contents

Each package contains the following:

• 1 x Oil Seal (Replaces 3863090, 3858303, 3853474, 3850482, 0915223, 0769349)
• Note: Some kits may also include an O-ring (3852865), Gasket, and/or Cotter Pin (306394). Please verify contents if these additional items are required.

Installation Guide

Professional installation is recommended. The general steps below are for reference only and may vary based on your specific drive model.

1. Drain the gearcase oil completely.
2. Remove the propeller from the propeller shaft.
3. Unbolt and carefully remove the propeller shaft bearing carrier from the lower unit.
4. Inspect the carrier and shaft for any damage, scoring, or wear.
5. Carefully pry out the old oil seal from the carrier, taking care not to damage the housing.
6. Clean the seal housing area thoroughly to remove any old sealant or residue.
7. Press the new oil seal squarely into the carrier using a suitable seal driver or socket. Ensure it is seated evenly and to the correct depth.
8. Apply a light coat of marine grease to the inner lip of the new seal.
9. Reinstall the bearing carrier, ensuring any O-rings or gaskets are correctly placed.
10. Torque the carrier bolts to the manufacturer's specified value.
11. Reinstall the propeller and refill the gearcase with the correct type and amount of oil.
12. Check for leaks after running the engine.

Troubleshooting & FAQ

Q: How can I confirm this seal fits my specific sterndrive model?

A: The best method is to cross-reference your existing part number with the numbers listed in our cross-reference table. You can also consult our detailed compatibility tables for OMC and Volvo Penta models. Pay close attention to the model names and year ranges (1994 and up for OMC).

Q: What are the signs that my propeller shaft oil seal is failing?

A: The most common sign of a failing seal is gear oil leaking from the propeller area. You may also notice fishing line or other debris wrapped around the propeller shaft, which can damage the seal. Another indicator is a "milky" or grayish appearance of the gear oil, which suggests water intrusion.

Q: My kit came with extra parts like an O-ring and gasket. Do I need them?

A: It depends on your specific sterndrive model and the components you are servicing. The large O-ring is typically for the bearing carrier housing. It is always a best practice to replace any O-rings or gaskets that are removed during the service to ensure a proper seal upon reassembly.

Q: OEM vs. Aftermarket?

This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.