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

Keep your Mercury 15 HP and 20 HP four-stroke outboard operating at peak performance with the Mercury 300 Hour Service Kit – 8M0120838. Designed for engines with serial numbers 0R235949 through 0R833819, this complete maintenance kit includes the key components required for the 300-hour service interval.

Routine maintenance at 300 hours helps refresh lubrication systems, maintain cooling performance, and replace wear items that experience heavy use over time. This kit packages the necessary oils, filtration components, ignition parts, cooling system components, and seals so you can complete the service efficiently and with confidence.

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
• 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

Why Perform the 300 Hour Service?

• Protect engine components: Fresh engine oil helps maintain proper lubrication and reduce wear.
• Maintain cooling efficiency: A new thermostat and impeller help ensure proper operating temperature.
• Reliable ignition performance: New spark plugs help promote clean starts and efficient combustion.
• Lower unit protection: Fresh gear lube and new seals help maintain proper gearcase lubrication.
• Corrosion protection: Replacing the anode helps defend internal components from electrolysis.

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