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Mercury | 300 Hour Service Kit | 15/20 HP | 8M0120838

The Mercury 300 Hour Service Kit – 8M0120838 provides the essential components required to perform the recommended 300-hour maintenance service on Mercury 15 HP and 20 HP four-stroke outboards with serial numbers 0R235949 through 0R833819. This kit combines the critical oils, filters, cooling system components, ignition parts, and seals needed to keep your engine running reliably.

Regularly performing scheduled maintenance helps protect your outboard’s internal components, maintain proper cooling performance, and ensure dependable operation on the water. This kit simplifies the service process by packaging the necessary maintenance parts together so you can efficiently complete the 300-hour interval service.

What’s Included in This Kit

• 2 x Quarts 25W-40 Synthetic Blend Engine Oil
• 1 x Quart Gear Lube
• 1 x Oil Filter
• 1 x Fuel Filter
• 1 x Oil Drain Seal
• 3 x Gearcase Drain Seals
• 1 x Thermostat
• 1 x Thermostat Gasket
• 2 x Spark Plugs
• 1 x Water Pump Impeller Kit
• 1 x Anode

Benefits of the 300 Hour Service

• Maintain engine lubrication with fresh 25W-40 synthetic blend oil.
• Protect the gearcase with new gear lube and drain seals.
• Maintain cooling system efficiency with a new thermostat and impeller.
• Improve ignition performance with fresh spark plugs.
• Prevent corrosion by replacing the sacrificial anode.

Engine Compatibility

• Mercury 15 HP Four-Stroke Outboards
• Mercury 20 HP Four-Stroke Outboards
• Serial Numbers 0R235949 – 0R833819

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

• Engine Application
  • 15 HP Carb 2 CYL - 0R235949-0R833819
  • 15 HP Carb 2 CYL JCI - 0R558208-0R833819
  • 20 HP Carb 2 CYL - 0R235168-0R833819
  • 10 HP Carb 2 CYL - 0R575531-0R833819