8M0090558 Maintenance Kit for Mercury 40HP 50HP 60HP EFI 4Cyl 4-Stroke | JLM Marine

8M0090558 Maintenance Kit for Mercury 40HP 50HP 60HP EFI 4Cyl 4-Stroke

This comprehensive maintenance kit is engineered for Mercury Quicksilver Marine 40HP, 50HP, and 60HP EFI 4-Cylinder 4-Stroke outboard motors. It provides all essential service components to keep your engine running reliably and efficiently.

This kit directly replaces OEM part number 8M0090558, consolidating critical maintenance items including thermostat, fuel filters (both low and high pressure), oil filter, and drain gaskets into one convenient package.

• Complete service solution for routine maintenance intervals
• Includes both low-pressure and high-pressure fuel filtration components
• All necessary gaskets and seals included for proper installation

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

• 1 × Thermostat (8M0168892)
• 1 × Thermostat Gasket (27-887978 & 27-8M0177107)
• 1 × Fuel Filter Assembly (low pressure) (35-879884T)
• 1 × Fuel Filter (high pressure) (35-8M0153652)
• 1 × Oil Filter (35-8M0162829)
• 1+3 × Drain Gaskets (26-8M0007119 & 26-8M0204693)

Note: This kit does NOT include a water pump repair kit.

Installation Guide

1. Ensure the engine is off and cool before beginning any maintenance work. Gather all necessary tools including wrenches, drain pan, and replacement parts from this kit.
2. Drain the engine oil by removing the drain plug and replacing the drain gasket with the new one provided. Install the new oil filter (35-8M0162829) after draining is complete.
3. Locate and replace the low-pressure fuel filter assembly (35-879884T) in the fuel system. Ensure all connections are secure to prevent leaks.
4. Replace the high-pressure fuel filter (35-8M0153652) following manufacturer torque specifications. Double-check all fuel line connections.
5. Remove the thermostat housing and install the new thermostat (8M0168892) with the new gasket (27-887978 & 27-8M0177107). Ensure proper seating and orientation.
6. Refill the engine with the manufacturer-recommended oil to the proper level. Start the engine and inspect all replaced components for leaks.
7. Run the engine at idle for several minutes and re-check oil level and all filter connections. Dispose of old filters and oil properly according to local regulations.

Troubleshooting & FAQ

Q: How do I confirm this maintenance kit fits my Mercury outboard?
A: Verify that your engine is a Mercury 40HP, 50HP, or 60HP EFI 4-Cylinder 4-Stroke model. Cross-reference your current part number with 8M0090558, or use the Mercury serial number guide and parts diagrams linked above to confirm compatibility.

Q: How often should I perform maintenance with this kit?
A: Follow Mercury's recommended service intervals, typically every 100 hours of operation or annually, whichever comes first. Oil and fuel filters should be replaced regularly to maintain optimal engine performance and longevity.

Q: Does this kit include everything I need for a complete service?
A: This kit includes thermostat, fuel filters (low and high pressure), oil filter, and drain gaskets. Note that it does NOT include a water pump repair kit, which may be required as part of your scheduled maintenance depending on engine hours and condition.

Q: What are signs that my fuel filters or thermostat need replacement?
A: Common symptoms include reduced engine performance, difficulty starting, overheating, rough idling, or loss of power under load. Regular preventive replacement avoids these issues before they occur.

Q: Can I install this maintenance kit myself or do I need a professional?
A: If you have mechanical experience and the proper tools, installation is straightforward following the steps above. However, professional installation is recommended to ensure all components are correctly installed and torqued to specification.

Q: Is this an OEM part or 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.