8M0181316 Maintenance Kit for Mercury 8HP 9.9HP | JLM Marine

8M0181316 Maintenance Kit for Mercury 8HP 9.9HP

This comprehensive maintenance kit is engineered for Mercury 8HP and 9.9HP carbureted outboards with serial numbers 0R042475 and above. It consolidates all essential service components—impeller, thermostat, gaskets, fuel filter, anode, and drain hardware—into one complete package, simplifying routine upkeep and extending engine life.

Designed as a direct replacement for OEM part number 8M0181316, this kit ensures compatibility and reliable performance across specified Mercury models. Each component meets OEM specifications for fit and function, enabling efficient maintenance intervals without sourcing individual parts.

• Includes water pump rebuild components (impeller, gaskets, guide plate, insert) for optimal cooling system performance
• Complete fuel and cooling system service parts: thermostat, fuel filter, and drain gaskets
• Sacrificial anode and gear oil pump included for comprehensive engine protection

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 maintenance kit includes the following components:

• 161586 (Gasket) × 1
• 161585 (Gasket) × 1
• 161587 (Gasket) × 1
• 8037531 (Guide Plate) × 1
• 8037511 (Insert) × 1
• 9521811 (Pin) × 1
• 8037481 (Impeller) × 1
• 16826 (Gasket) × 4
• 161268 (Screw) × 4
• 8M0119207 (Thermostat) × 1
• 27-853702005 (Thermostat Gasket) × 1
• 35-8M0157133 (Fuel Filter) × 1
• 12-895146 (Gasket) × 1
• 12-191833 (Drain Gasket) × 2
• 27-95220 (Drain Gasket) × 2
• 8150264 (Cotter Pin) × 1
• 823912 (Anode) × 1
• 24OP149 (Gear Oil Pump) × 1

Installation Guide

1. Preparation: Disconnect the fuel line and remove the lower unit from the outboard. Drain all gear oil completely before proceeding.
2. Water Pump Disassembly: Remove the water pump housing cover and extract the old impeller, guide plate, and insert. Inspect the housing for scoring or corrosion.
3. Install New Impeller: Lubricate the new impeller (8037481) with glycerin or soapy water, then install it with blades oriented correctly. Insert the guide plate (8037531) and insert (8037511), securing with pin (9521811).
4. Gasket Replacement: Remove old gaskets (161586, 161585, 161587) from mating surfaces and clean thoroughly. Install new gaskets without adhesive unless specified by the service manual.
5. Reassemble Water Pump: Reinstall the water pump housing using the four screws (161268) and gaskets (16826). Torque screws evenly in a cross pattern to prevent leaks.
6. Thermostat Service: Access the thermostat housing, remove the old thermostat (8M0119207), and replace it along with the gasket (27-853702005). Ensure proper seating to maintain correct operating temperature.
7. Fuel Filter Replacement: Locate the inline fuel filter, disconnect fuel lines, and replace with the new filter (35-8M0157133). Ensure proper flow direction as marked on the filter housing.
8. Drain Plug Gaskets: Replace drain plug gaskets (12-191833 and 27-95220) on both the lower unit and any oil reservoir access points. Do not overtighten drain plugs.
9. Anode Inspection: Remove the old sacrificial anode (823912) and inspect the mounting surface. Install the new anode and secure with the cotter pin (8150264).
10. Gear Oil Refill: Using the included gear oil pump (24OP149), refill the lower unit with manufacturer-recommended gear oil until it flows from the upper vent. Replace gasket (12-895146) and reinstall plugs.
11. Final Assembly: Reattach the lower unit to the outboard, ensuring proper alignment of shift linkage and water tube. Reconnect the fuel line and check for leaks.
12. System Check: Start the engine in a test tank or on muffs and verify consistent water stream from the telltale outlet. Monitor for fuel leaks and proper operating temperature.

Troubleshooting & FAQ

Q: How do I confirm this maintenance kit fits my Mercury outboard?
A: Verify that your engine is an 8HP or 9.9HP carbureted Mercury outboard with serial number 0R042475 or higher. Cross-check the OEM part number 8M0181316 in your service manual or on Mercury's parts diagram to ensure compatibility.

Q: How often should I perform maintenance with this kit?
A: Mercury recommends annual maintenance or every 100 hours of operation, whichever comes first. Replace the impeller and inspect the thermostat yearly; replace the fuel filter and drain gaskets during each service interval to prevent cooling and fuel system failures.

Q: What are the signs that I need to replace the impeller or thermostat?
A: A weak or absent telltale water stream, engine overheating, or reduced cooling performance indicate impeller failure. If the engine runs too cool or too hot despite a functioning water pump, the thermostat may be stuck open or closed and requires replacement.

Q: Can I reuse the old gaskets if they appear undamaged?
A: No, always replace gaskets during maintenance even if they look intact. Compressed gaskets lose their sealing properties and can cause water or oil leaks, compromising engine performance and leading to costly damage.

Q: Is this an OEM kit or an aftermarket replacement?
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.