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Mercury | 300 Hour Service Kit | 20/30 HP | 8M0120839

The Mercury 300 Hour Service Kit – 8M0120839 provides the essential maintenance components needed to service Mercury 20 HP and 30 HP four-stroke outboards with serial numbers 0R106999 and above. This comprehensive maintenance kit bundles the key oils, filters, cooling system components, ignition parts, and seals required for the 300-hour service interval.

Routine maintenance at recommended service intervals helps maintain reliable engine performance, protect internal components, and extend the life of your outboard. This kit simplifies the process by including the common wear components that should be replaced during the 300-hour service, ensuring your Mercury outboard continues operating efficiently and reliably.

What’s Included in This Kit

• 2 x Quarts 10W-30 Engine Oil
• 1 x Quart Gear Lube
• 1 x Oil Filter
• 1 x Fuel Filter
• 1 x Oil Drain Seal
• 2 x Gearcase Drain Seals
• 1 x Thermostat
• 1 x Thermostat Gasket
• 3 x Spark Plugs
• 1 x Water Pump Impeller Kit
• 1 x Anode

Benefits of Performing the 300 Hour Service

• Maintain proper engine lubrication with fresh engine oil.
• Protect the gearcase with new gear lube and drain seals.
• Ensure cooling system efficiency with a new thermostat and impeller.
• Improve ignition reliability with fresh spark plugs.
• Prevent corrosion by replacing the sacrificial anode.

Engine Compatibility

• Mercury 20 HP Four-Stroke Outboards
• Mercury 30 HP Four-Stroke Outboards
• Serial Numbers 0R106999 and Above

Always verify your Mercury outboard serial number before ordering to ensure proper compatibility.

• Engine Application
  • 25 HP EFI Jet 3 CYL - 0R165086-1R162636
  • 30 HP EFI 3 CYL - 0R106999-1R162636
  • 25 HP EFI 3 CYL - 0R106999-1R162636
  • 25 HP Carb SeaPro - 0R051710 and up