8M0088080 Gearcase Seal Kit for Mercury EFI | JLM Marine

8M0088080 Gearcase Seal Kit for Mercury EFI Outboards

This gearcase seal kit is engineered to fit Mercury EFI outboard motors ranging from 65HP to 115HP, including standard, Sea Pro, Pro XS, and JET configurations. Designed for 2.07:1 standard rotation gear housings with serial numbers 2B095049 & Up (and 2B225488 & Up for 115HP Pro XS models), this kit provides essential sealing components for both driveshaft and propeller shaft maintenance.

The kit directly replaces Mercury OEM part number 8M0088080, ensuring proper fitment across multiple Mercury EFI model families. It is suitable for both gear housing driveshaft and propeller shaft seal service on compatible engines.

• Fits Mercury EFI outboards: 65HP, 75HP, 80HP, 90HP, 100HP, and 115HP models
• Compatible with standard rotation 2.07:1 gear housings
• Designed for driveshaft and propeller shaft seal replacement

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. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

This gearcase seal kit includes all necessary seals and components for servicing your Mercury EFI outboard's gear housing. Please verify the individual seals and gaskets against your service manual or exploded diagram to ensure complete compatibility with your specific model and serial number.

Installation Guide

1. Disconnect the battery and remove the outboard's lower unit following your service manual instructions. Drain all gearcase oil completely.
2. Clean the mating surfaces of the gear housing thoroughly, removing old sealant and debris to ensure proper seal seating.
3. Remove the old driveshaft and propeller shaft seals using appropriate seal removal tools; take care not to damage housing surfaces.
4. Inspect the gear housing for cracks, corrosion, or scoring that may compromise new seal performance.
5. Lubricate new seals with marine-grade grease and carefully install them into their respective bores using proper seal drivers.
6. Ensure each seal is seated evenly and at the correct depth as specified in your service manual.
7. Reinstall the driveshaft and propeller shaft, verifying smooth rotation and correct alignment.
8. Reassemble the lower unit to the gear housing using new gaskets and appropriate marine sealant where specified.
9. Refill the gearcase with the manufacturer's recommended gear oil to the proper level; check for leaks.
10. Reinstall the lower unit onto the outboard motor, torquing all fasteners to specification.
11. Run the engine in a test tank or on the water, then recheck gearcase oil level and inspect for leaks after initial operation.

Troubleshooting & FAQ

Q: How do I confirm this seal kit fits my specific Mercury outboard?
A: Cross-reference your engine's serial number with the compatibility table above. Your serial number should be 2B095049 or higher (or 2B225488 & Up for 115HP Pro XS). Additionally, verify your gear housing is the 2.07:1 standard rotation type by checking your owner's manual or the gear housing identification tag.

Q: What are the signs that my gearcase seals need replacement?
A: Common symptoms include gear oil leaking from the lower unit, milky or contaminated gear oil (indicating water intrusion), difficulty shifting gears, or unusual noise from the lower unit. Regular inspection during oil changes is recommended.

Q: How often should I replace gearcase seals?
A: Gearcase seals should be inspected annually and replaced as needed based on condition. Typical replacement intervals range from 2–5 years depending on usage, operating conditions, and maintenance practices. Always replace seals during lower unit overhauls or if any seal damage is detected.

Q: Can I install this kit myself or do I need a professional?
A: Installation requires mechanical aptitude, specialized tools (seal drivers, torque wrench), and familiarity with lower unit disassembly. If you lack experience with outboard lower unit service, professional installation is strongly recommended to avoid costly damage.

Q: Does this kit include all seals needed for a complete lower unit rebuild?
A: This kit contains gearcase seals for the driveshaft and propeller shaft assemblies. Verify contents against your service manual's parts diagram, as additional gaskets, O-rings, or bearings may be required depending on the scope of your service.

Q: Is this an OEM or aftermarket seal kit?
A: 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?
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.