Mercury Gearcase Seal Kit – Fits Mercury/Mariner 65-115HP 4-Stroke Outboards (Replaces 8M0088080)
Mercury Gearcase Seal Kit – Fits Mercury/Mariner 65-115HP 4-Stroke Outboards (Replaces 8M0088080) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Mercury Gearcase Seal Kit – Fits Mercury/Mariner 65-115HP 4-Stroke ...
Product Details
This Mercury Gearcase Seal Kit is an aftermarket replacement designed for Mercury and Mariner 65-115HP 4-stroke outboards (serial number 2B095049 and up) with a 2.07:1 standard rotation gearcase. It provides a reliable solution for stopping leaks and preventing water intrusion into your lower unit.
This kit is a direct interchange for Mercury OEM part number 8M0088080, ensuring proper fit and function for a complete gearcase reseal.
- Designed for direct OEM-equivalent installation.
- Engineered for standard rotation 2.07:1 ratio gearcases.
- Includes all necessary seals for a driveshaft and propeller shaft service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 8M0088080 |
Engine & Model Compatibility
Confirm your engine model in the table below. This kit is specifically for Mercury/Mariner outboards with serial numbers 2B095049 and higher.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercury | 65 EFI | 65 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 65 EFI | 65 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 75 EFI | 75 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 75 EFI | 75 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 75 Pro EFI | 75 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 75 Pro EFI | 75 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 80 EFI | 80 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 80 EFI | 80 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 80 Jet EFI | 80 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 80 Jet EFI | 80 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 90 EFI | 90 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 90 EFI | 90 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 90 Pro EFI | 90 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 90 Pro EFI | 90 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 100 EFI | 100 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 100 EFI | 100 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 115 EFI | 115 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 115 EFI | 115 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 115 Pro XS EFI | 115 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 115 Pro XS EFI | 115 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
| Mercury | 115 Pro EFI | 115 | 4-Stroke | 8M0088080 | Gear Housing, Driveshaft, 2.07:1 Standard Rotation |
| Mercury | 115 Pro EFI | 115 | 4-Stroke | 8M0088080 | Gear Housing, Propeller Shaft, 2.07:1 Standard Rotation |
Technical Specs
- Product Type
- Gearcase Seal Kit
- Installation
- OEM replacement
- Application
- For standard rotation 2.07:1 ratio gearcase
- Product Dimensions
- 17.0" L x 14.0" W x 5.0" H
- Replaces OEM
- 8M0088080
What’s in the Box
- 1 x Complete Gearcase Seal Kit (Replaces 8M0088080)
Installation Notes
- Position the outboard vertically and place a drain pan below the gearcase.
- Remove the upper (vent) and lower (drain) gear lube screws and allow the oil to drain completely.
- Disconnect the shift linkage and remove the gearcase mounting bolts. Carefully lower and remove the gearcase from the engine.
- Disassemble the gearcase components, including the water pump, driveshaft bearing carrier, and propeller shaft carrier, following your service manual's instructions.
- Carefully remove all old seals, O-rings, and gaskets from their respective bores and shafts. Clean all sealing surfaces thoroughly.
- Install the new seals and O-rings from the kit, ensuring they are properly seated and lubricated with a light coat of marine grease.
- Reassemble the gearcase components in reverse order of disassembly, torquing all fasteners to the manufacturer's specifications.
- Reinstall the gearcase, reconnect the shift linkage, and refill with new gear lube before testing.
Troubleshooting & FAQ
How do I know if this seal kit fits my Mercury outboard?
This kit is for Mercury/Mariner 65-115HP 4-stroke models with serial numbers 2B095049 and up, specifically for the standard rotation 2.07:1 gearcase. Always cross-reference your engine model and OEM part number (8M0088080) with our compatibility chart.
What are the signs my gearcase seals are failing?
Common symptoms include milky or discolored gear lube (indicating water intrusion), visible oil leaks around the propeller shaft or driveshaft, or excessive metal shavings on the magnetic drain plug.
Is this kit for a standard or counter-rotation gearcase?
This kit is designed specifically for the standard (right-hand) rotation, 2.07:1 ratio gearcase. It is not compatible with counter-rotation models.
Do I need special tools for installation?
While basic tools are sufficient for disassembly, you may need a seal puller for removing old seals and a seal driver or appropriately sized socket for installing new ones without damage. A service manual for your specific outboard is highly recommended.
What’s the difference between OEM and this aftermarket part?
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.
How fast is shipping?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
What is the warranty and return policy?
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 and specifications against 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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