8M0088081 Gearcase Seal Kit for Mercury 65HP EFI JET 75HP EFI 75HP EFI Sea Pro 80HP EFI 80HP EFI JET 90HP EFI 90HP EFI Sea Pro 100HP EFI 115HP EFI 115HP EFI Sea Pro 115HP EFI Pro XS | JLM Marine

Gearcase Seal Kit – Fits Mercury 65HP–115HP EFI Outboards (OEM 8M0088081)

This gearcase seal kit is engineered for Mercury EFI outboards ranging from 65HP to 115HP, including standard, Sea Pro, Pro XS, and JET models. Designed to service both driveshaft and propeller shaft housings with 2.38:1 gear ratios, it ensures reliable sealing and protection for your lower unit.

Direct replacement for Mercury OEM part number 8M0088081. Compatible with serial numbers 2B095049 & Up for most models and 2B225488 & Up for 115HP EFI Pro XS engines.

• Fits both standard and counter rotation gearcases
• Suitable for gear housing, driveshaft, and propeller shaft sealing
• Covers Mercury EFI outboards: 65HP JET, 75HP, 80HP, 90HP, 100HP, and 115HP models

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 kit includes all seals required for servicing the gearcase assembly on compatible Mercury EFI outboards.

Installation Guide

1. Disconnect the battery and remove the propeller. Drain all lower unit oil completely before beginning disassembly.
2. Remove the lower unit from the outboard following your service manual's instructions. Clean all mating surfaces thoroughly.
3. Carefully remove old seals from the driveshaft and propeller shaft housings using appropriate seal removal tools. Inspect shafts for scoring or damage.
4. Clean seal grooves and apply a thin coat of marine-grade grease to new seals before installation.
5. Install new driveshaft seals using a proper seal driver, ensuring they are seated evenly and fully into their housings.
6. Install propeller shaft seals in the same manner, taking care not to damage seal lips during installation.
7. Reassemble the lower unit, ensuring all O-rings and gaskets are properly positioned. Torque all fasteners to factory specifications.
8. Refill the lower unit with the correct type and quantity of gear oil. Check for leaks before reinstalling the propeller and reconnecting the battery.

Troubleshooting & FAQ

Q: How do I confirm this seal kit fits my Mercury outboard?
A: Verify your engine's model, horsepower, and serial number against the compatibility table above. For 115HP Pro XS models, ensure your serial is 2B225488 or higher; for all other listed models, 2B095049 or higher. You can also cross-reference part number 8M0088081 in your engine's parts diagram.

Q: How often should I replace my gearcase seals?
A: Replace seals whenever you notice lower unit oil contamination (milky appearance), leaks around the gearcase, or during major lower unit service. Inspect seals annually if you operate in harsh saltwater or high-hour conditions.

Q: What are common signs of failing gearcase seals?
A: Watch for gear oil leaking from the lower unit, water mixing with gear oil (indicated by a milky color), decreased performance, or unusual noise from the lower unit. Address seal failure immediately to prevent bearing and gear damage.

Q: Can I install this kit myself or do I need a professional?
A: Installation requires lower unit disassembly, seal removal tools, and torque specifications. If you have mechanical experience and the proper tools, you can install it yourself following your service manual. Otherwise, professional installation is recommended to ensure proper sealing and avoid costly damage.

Q: OEM vs. Aftermarket?
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.