Want to know more about how your engine is breaking-in or wearing? Curious about whether or not your oil is doing its job? Want to be ahead of problems that may develop? PartsVu has partnered with Blackstone Laboratories and we are now offering professional oil analysis kits. Results are typically received in a few days via email. Shop now.

Mercury | 300 Hour Service Kit | 8M0113483

Stay on schedule with a complete 300 hour service kit designed for Mercury 40, 50, and 60 HP four-stroke outboards equipped with standard gearcases. Built around 10W-30 four-stroke oil, this kit includes the routine oil and gearcase service items along with the cooling, ignition, and corrosion components commonly replaced at the 300 hour interval. It is a convenient way to refresh critical systems and help maintain dependable performance season after season.

Application: Mercury 40/50/60 HP Four-Stroke – Standard Gearcases Only-8M0113483

What’s Included in This Kit

• 1x 10W-30 Four-Stroke Engine Oil (Gallon)
• 1x Gear Lube (Quart)
• 1x Oil Filter
• 1x Low Pressure Fuel Filter
• 1x High Pressure Fuel Filter
• 1x Oil Drain Seal
• 2x Gearcase Drain Seals
• 1x Thermostat
• Thermostat Gaskets (Included)
• 4x Spark Plugs
• 1x Water Impeller Repair Kit
• 1x Power Trim Anode
• 1x Lower Unit Anode

Why This 300 Hour Service Kit Matters

• Complete milestone coverage: Addresses oil, gearcase, cooling, ignition, and fuel system wear items.
• Cooling system refresh: Thermostat and impeller service help maintain proper operating temperature.
• Fuel system protection: Replacing both low and high pressure fuel filters supports clean fuel delivery.
• Corrosion protection: Includes trim and lower unit anodes to help reduce galvanic corrosion.

FAQ

Does this kit fit Command Thrust or other specialty gearcases?
No. This kit is specifically for models equipped with standard gearcases only.

Why are 2 gearcase drain seals included?
Most gearcases use sealing washers at both the drain and vent screws. Replacing both helps ensure a proper seal after service.

Why replace both fuel filters at 300 hours?
Fuel filters can accumulate debris and moisture over time. Replacing both supports consistent fuel pressure and engine performance.

What should I verify before ordering?
Confirm your engine horsepower and that it is equipped with a standard gearcase.

• Engine Application
  • 40 HP EFI Jet 4 CYL - 1C453840 and up
  • 50 HP EFI 4 CYL - 1C453840 and up
  • 60 HP EFI 4 CYL - 1C453840 and up
  • 60 HP EFI SeaPro 4 CYL - 1C453840 and up
  • 40 HP EFI SeaPro 4 CYL - 1C453840 and up
  • 35 HP EFI Jet 4 CYL - 1C453840 and up
  • 40 HP EFI 4 CYL - 1C453840 and up