8M0120657 Maintenance Kit for Mercury | JLM Marine

8M0120657 Maintenance Kit for Mercury

This comprehensive maintenance kit is designed to fit Mercury outboard engines, providing all the essential components needed for routine service. It includes high-quality oil filters, fuel filters, drain gaskets, and a gear oil pump to keep your engine running smoothly and reliably.

Direct Replacement for OEM Part Number: 8M0120657

• Complete service kit with oil filter, fuel filter, drain gaskets, and gear oil pump
• Includes all necessary gaskets for proper sealing during maintenance
• Designed for Mercury outboard engines

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.

Please verify compatibility with your specific Mercury outboard engine model and year before purchasing.

Package Contents

This maintenance kit includes the following components:

• 877769K01 (Oil Filter) × 1
• 8M0095659 (Fuel Filter) × 1
• 888593.0 (Oil Plug Drain Gasket) × 1
• 830749.0 (Lower Unit Drain Gasket) × 2
• 24OP149 (Gear Oil Pump) × 1
• 888593 (Oil Plug Drain Gasket) × 1
• 830749 (Lower Unit Drain Gasket) × 2

Installation Guide

1. Warm up the engine for a few minutes to thin the oil for easier drainage. Position the boat or engine so it sits level.
2. Place a suitable container beneath the engine and remove the oil drain plug using the appropriate wrench. Allow all old oil to drain completely.
3. Replace the old oil plug drain gasket (888593) with the new one provided in the kit. Reinstall the drain plug and torque to manufacturer specifications.
4. Remove the old oil filter (877769K01) by turning it counterclockwise. Clean the mounting surface and apply a thin layer of fresh oil to the new filter's gasket.
5. Install the new oil filter by hand, tightening it according to the instructions printed on the filter. Refill the engine with the correct grade and quantity of oil.
6. Locate the fuel filter (8M0095659) in the fuel system. Relieve fuel pressure and disconnect fuel lines carefully.
7. Remove the old fuel filter and install the new one, ensuring the flow direction arrow points toward the engine. Reconnect fuel lines securely.
8. For lower unit service, position a container under the lower unit drain and vent plugs. Remove both plugs to allow old gear oil to drain completely.
9. Replace the lower unit drain gaskets (830749) on both the drain and vent plugs with the new gaskets provided (two pairs included).
10. Using the included gear oil pump (24OP149), inject fresh gear oil into the lower drain hole until oil flows from the upper vent hole. Install the vent plug first, then the drain plug.
11. Start the engine and check for leaks around all filter and plug locations. Monitor oil pressure and ensure proper operation.
12. Dispose of used oil, filters, and gaskets properly according to local environmental regulations. Record the service date and engine hours for future maintenance tracking.

Troubleshooting & FAQ

Q: How do I confirm this maintenance kit fits my Mercury engine?
A: Verify that your engine requires OEM part number 8M0120657. Check your owner's manual or use the Mercury Serial Number Guide linked above to identify your exact model and confirm compatibility.

Q: How often should I perform this maintenance service?
A: Follow Mercury's recommended maintenance schedule, typically every 100 hours of operation or annually, whichever comes first. Engines used in harsh conditions may require more frequent service.

Q: Can I reuse the old gaskets if they look intact?
A: No, always replace drain gaskets during service. Reusing old gaskets can result in improper sealing, leading to leaks and potential damage to your engine or lower unit.

Q: What are the signs that I need to replace my oil and fuel filters?
A: Common signs include reduced engine performance, hard starting, rough idling, decreased fuel efficiency, or visible contamination in the fuel system. Regular replacement prevents these issues.

Q: Is this an OEM or aftermarket maintenance 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.