Outdrive Mounting Gasket Kit – Fits Volvo Penta SX/DP Drives & OMC Cobra Sterndrives (Replaces 508105, 915840)

Outdrive Mounting Gasket Kit – Fits Volvo Penta SX/DP Drives & OMC Cobra Sterndrives

This gasket kit provides a reliable seal where the sterndrive assembly attaches to the transom shield. It is designed for OMC Cobra Sterndrives (1986–1993) and a variety of Volvo Penta SX-series and DP drives.

This kit is a direct replacement for multiple OEM part numbers, including OMC 508105 / 915840 and Volvo Penta 3852560 / 3852565.

• Installation Type: Direct replacement for a secure fit.
• Material: Manufactured from high-quality, OEM-specification rubber and composite materials.
• Complete Kit: Includes the main gasket, seal, and O-rings required for installation.

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 Applications

Volvo Penta Applications

Technical Specifications

Package Contents

• 1 x Outdrive Mounting Gasket (Replaces OMC 508105/915840)
• 1 x Outdrive Seal
• 2 x O-rings

Installation Guide

Follow these general steps for installation. Always refer to your engine’s official service manual for detailed procedures and torque specifications.

1. Safety First: Disconnect the boat's battery before beginning any work. Place the drive in the forward gear position.
2. Drain Fluids: Drain the gear lube from the sterndrive completely.
3. Remove Drive: Disconnect the trim/tilt rams and remove the six mounting nuts that secure the sterndrive to the transom shield. Carefully pull the drive assembly away from the boat.
4. Clean Surfaces: Remove the old gasket, seal, and O-rings. Thoroughly clean both mating surfaces on the transom shield and the drive to remove any old sealant or corrosion.
5. Install New Gasket: Place the new rectangular seal in the groove of the transom housing. Fit the new gasket over the studs. Position the new O-rings for the oil and water passages correctly.
6. Reinstall Drive: Carefully guide the sterndrive back onto the transom shield, ensuring the driveshaft aligns with the engine coupler.
7. Secure and Torque: Hand-tighten the six mounting nuts, then torque them to the manufacturer's specified value and sequence. Reconnect the trim/tilt rams.
8. Final Checks: Refill the sterndrive with the correct type and amount of gear lube. Check for any leaks around the newly sealed area. Reconnect the battery.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my sterndrive?
A: This kit is designed for OMC Cobra Sterndrives (1986–1993) and various Volvo Penta SX and DP drives (approx. 1994–2008). Verify that your original part number matches one of the numbers listed in our Part Number Cross-Reference table, such as OMC 508105 or Volvo Penta 3852560.

Q: What are the symptoms of a failing outdrive mounting gasket?
A: The most common sign is water leaking into the boat's bilge area from around the transom assembly. You may also notice gear lube leaking out of the boat. A visual inspection might reveal a cracked, brittle, or deteriorated gasket if the drive is removed.

Q: How often should I replace this gasket set?
A: As a best practice, this gasket kit should be replaced anytime the sterndrive is removed from the transom shield for service. This preventative measure ensures a fresh, reliable seal and prevents leaks.

Q: Is this an OEM part?
A: This listing is an aftermarket replacement part, not an OEM component. We build our parts to meet or exceed 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?
A: 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?
A: 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.