Outdrive Mounting Gasket Set – Fits OMC & Volvo Penta SX Drives (Replaces 508105, 915840)
Outdrive Mounting Gasket Set – Fits OMC & Volvo Penta SX Drives (Replaces 508105, 915840) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Outdrive Mounting Gasket Set – Fits OMC & Volvo Penta SX Drives...
Product Details
This Outdrive Mounting Gasket Set is designed for OMC Cobra Sterndrives from 1986–1993 and various Volvo Penta SX-series drives, including SX-S, SX-C, SX-R, SX-M, and DP-S models. It ensures a proper seal where the sterndrive assembly attaches to the transom.
This kit serves as a direct replacement for OMC part numbers 508105 and 915840; Volvo Penta 3852560 and 3852565; Sierra 18-2613; GLM 39630; and Mallory 9-62605.
- Direct replacement fit for simplified installation.
- Constructed from durable, OEM-specification materials for longevity.
- Includes the essential mounting gasket, seal, and O-rings for a complete service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| OMC | 508105 |
| OMC | 915840 |
| OMC | 0915840 |
| OMC | 0508105 |
| OMC | 0911836 |
| Volvo Penta | 3852560 |
| Volvo Penta | 3852565 |
| Volvo Penta | 911823 |
| Volvo Penta | 911851 |
| Sierra | 18-2613 |
| GLM | 39630 |
| Mallory | 9-62605 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For OMC engines, this gasket fits Cobra sterndrives paired with 4-cylinder, V6, and V8 engines within the specified displacement range from 1986 to 1993.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| OMC | Cobra Sterndrives | 85–130 | 4-Stroke | 1986–1993 | 508105 | 2.3-3.0L 4-cylinder engines |
| OMC | Cobra Sterndrives | 160–165 | 4-Stroke | 1986–1993 | 508105 | 4.3L V6 engines |
| OMC | Cobra Sterndrives | 185–240 | 4-Stroke | 1986–1993 | 508105 | 5.0-5.7L V8 engines |
For Volvo Penta engines, this gasket fits SX and DP-S series sterndrives where the drive unit mounts to the transom assembly.
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Volvo Penta | SX-S Drives | 4-Stroke | 3852560 | Used at transom assembly |
| Volvo Penta | SX-C Drives | 4-Stroke | 3852560 | Used at transom assembly |
| Volvo Penta | SX-R Drives | 4-Stroke | 3852560 | Used at transom assembly |
| Volvo Penta | SX-M Drives | 4-Stroke | 3852560 | Used at transom assembly |
| Volvo Penta | DP-S Drives | 4-Stroke | 3852560 | Used at transom assembly |
Technical Specs
- Product Type
- Outdrive/Sterndrive Mounting Gasket Set
- Installation
- Direct replacement
- Housing Material
- OEM-specification materials
- Weight
- Approximately 0.14 lbs (0.06 kg)
- Other Technical Attributes
- Includes mounting gasket, seal, and O-rings
What’s in the Box
- 1 x Outdrive Mounting Gasket (OMC 508105/915840)
- 1 x Outdrive Seal
- 2 x O-rings
Installation Notes
- Disconnect the battery and ensure the engine is off and cool.
- Remove the sterndrive unit from the transom shield according to the manufacturer's service manual.
- Carefully remove the old mounting gasket, seal, and O-rings. Clean both mating surfaces thoroughly, removing all old gasket material and corrosion.
- Inspect the surfaces for pitting or damage that could prevent a proper seal.
- Position the new gasket, seal, and O-rings correctly onto the transom housing.
- Reinstall the sterndrive unit, ensuring it is properly aligned.
- Torque all mounting bolts to the manufacturer's specified values in the recommended sequence.
- Once assembled, check for leaks before operating the vessel in water.
Troubleshooting & FAQ
How do I know if my outdrive mounting gasket is failing?
The most common sign of a failing mounting gasket is water leaking into the bilge area from the transom, especially when the boat is in the water. You may also notice corrosion around the mounting bolts or visible damage to the old gasket upon inspection.
Is this gasket compatible with both OMC Cobra and Volvo Penta SX drives?
Yes, this gasket kit is designed to fit OMC Cobra sterndrives made between 1986 and 1993, as well as a wide range of Volvo Penta SX and DP-S series drives. Refer to the compatibility tables to confirm your specific model.
What is the recommended replacement interval for this gasket?
There is no fixed replacement interval. This gasket should be replaced any time the sterndrive is removed from the transom for service, or if a leak is detected. It is considered a single-use seal.
Does this kit include sealant?
No, sealant is not included. While some applications may recommend a sealant, always follow your specific service manual's instructions. In many cases, this gasket is designed to be installed dry on clean, smooth surfaces.
Can I reuse my old O-rings or gasket?
No. Gaskets, seals, and O-rings are designed for one-time use. Reusing old components can lead to leaks and water damage. Always use new components from the kit when reinstalling the sterndrive.
What is the difference between this and the OEM part?
This is an aftermarket replacement part, not an original OEM component. It is engineered to meet or exceed OEM specifications for fit, material durability, and sealing performance, offering a reliable alternative at a better value.
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.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
