Outdrive Mounting Gasket Kit – Fits Volvo Penta, OMC Cobra (Replaces 508105, 915840)
Outdrive Mounting Gasket Kit – Fits Volvo Penta, OMC Cobra (Replaces 508105, 915840) is backordered and will ship as soon as it is back in stock.
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Outdrive Mounting Gasket Kit – Fits Volvo Penta, OMC Cobra (Replace...
Outdrive Mounting Gasket Kit – Fits Volvo Penta, OMC Cobra (Replaces 508105, 915840) is backordered and will ship as soon as it is back in stock.
Product Details
This outdrive mounting gasket kit provides a replacement sealing solution where the sterndrive assembly attaches to the transom shield. It is intended for OMC Cobra sterndrives manufactured from 1986 through 1993, along with selected Volvo Penta SX-series and DP drives.
The kit is listed as a replacement for OMC references 508105 and 915840 and cross-references other OEM and aftermarket numbers shown below. Always compare the original part number, drive model, and gasket configuration before installation.
- Designed as a direct replacement for applicable outdrive mounting gasket assemblies.
- Uses rubber and composite sealing components for the transom mounting area.
- Includes a mounting gasket, seal, and O-rings for the applications identified in this listing.
Part Number Matrix
Use the following references to help identify the applicable replacement. Part-number cross-references should be confirmed against the specific drive and transom assembly.
| Brand | Part Number |
|---|---|
| OMC | 508105 |
| OMC | 915840 |
| OMC | 0508105 |
| OMC | 0915840 |
| 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 the exact sterndrive model, year, transom assembly, and existing part number before ordering. The applications below summarize the fitment information associated with this replacement gasket kit.
For OMC applications, the kit is listed for Cobra sterndrives used with 4-cylinder, V6, and V8 engines from 1986 through 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 applications, this kit is listed for selected SX and DP-S series drives used at the transom assembly, approximately 1994–2008. Exact fitment can vary by drive variant and production details.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Volvo Penta | SX Drives | Various | 4-Stroke | 1994–2008 | 3852560 | SX-S, SX-C, SX-R, and SX-M variants |
| Volvo Penta | DP-S Drives | Various | 4-Stroke | 1994–2008 | 3852560 | Used at the transom assembly |
Technical Specs
- Product Type
- Outdrive/sterndrive mounting gasket kit
- Installation
- Direct replacement for applicable assemblies
- Material
- Rubber and composite sealing materials
- Weight
- Approximately 0.06 kg (0.14 lb)
- Included Components
- Mounting gasket, seal, and O-rings
What’s in the Box
- 1 × Outdrive mounting gasket, replacing applicable OMC 508105/915840 applications
- 1 × Outdrive seal
- 2 × O-rings
Installation Notes
- Disconnect the battery and make sure the engine is switched off and cool.
- Raise the outdrive fully and support it safely.
- Remove the trim-tilt rams and shift cable from the drive as required by the service procedure for your model.
- Remove the six mounting nuts and carefully separate the sterndrive assembly from the transom shield.
- Remove the old gasket, seal, and O-rings. Thoroughly clean the mating surfaces and remove old sealant, debris, and corrosion.
- Apply an appropriate marine-grade sealant where required by the manufacturer's service procedure.
- Install the new gasket, seal, and O-rings in their correct positions.
- Carefully reinstall the sterndrive, making sure the drive shaft aligns correctly with the engine coupler.
- Tighten the mounting nuts to the manufacturer's specified torque.
- Reconnect the trim-tilt rams and shift cable.
- Lower the drive, check fluid levels, and inspect for leaks and proper operation before returning the vessel to service.
Troubleshooting & FAQ
How can I confirm this gasket kit fits my specific model?
Cross-reference the existing part number with the Part Number Matrix and compare the drive model, year, transom assembly, gasket shape, and component arrangement. If any of these details differ, consult the applicable service information before ordering.
What are the signs of a failed outdrive mounting gasket?
Possible signs include water entering the bilge near the transom, visible corrosion around the sterndrive mounting flange, or a drive assembly that feels loose. Continued water ingress can cause additional damage, so investigate leaks promptly.
Is any special sealant required for installation?
Use a compatible marine-grade sealant only where required by the service procedure for the specific sterndrive. Follow the sealant manufacturer's instructions and the applicable manufacturer's torque and installation requirements.
How often should this gasket be replaced?
There is no universal fixed replacement interval. Replace the gasket whenever the sterndrive is removed from the transom for service or whenever deterioration or leakage is found.
Can I install this gasket myself?
Installation may be possible for an experienced marine mechanic, but sterndrive removal and reinstallation require correct support, alignment, torque, and leak testing. Professional installation is recommended when the required service equipment or specifications are not available.
Is this kit for saltwater and freshwater use?
The kit is intended for the listed marine sterndrive applications. Proper surface preparation, sealant selection, corrosion protection, and routine inspection remain important in both saltwater and freshwater service.
Is this an OEM component?
No. This listing is for an aftermarket replacement gasket kit. The references in the Part Number Matrix are provided for identification and cross-reference purposes.
Shipping speed and cost
Shipping methods, delivery estimates, and costs are displayed at checkout based on the destination and available service.
Warranty and returns
Warranty and return eligibility are governed by the applicable store policies. Contact support with your order details if you need assistance.
Safety & Important Information
- Verify the drive model, year, original part number, and gasket configuration before purchase.
- This is an aftermarket replacement, not an OEM component.
- Follow the applicable service manual for lifting, support, sealant, alignment, torque, and leak-testing procedures.
- Professional installation is recommended when sterndrive service experience or appropriate equipment is not available.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for dependable service in real-world applications.
- Global Fulfillment — Available shipping methods and delivery estimates are shown during checkout.
- Manufacturer-Direct Value — We aim to provide practical replacement solutions with consistent product information.
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