Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 10W-30 - 8M0120837 - S/N 0R042475 & Above
Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 10W-30 - 8M0120837 - S/N 0R042475 & Above
Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 10W-30 - 8M0120837 - S/N 0R042475 & Above is backordered and will ship as soon as it is back in stock.
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Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Ge...
Description
Description
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 | 8M0120837
Keep your small-horsepower Mercury running strong with a complete 300 hour service kit designed for 8 HP and 9.9 HP carbureted (209cc) four-stroke outboards equipped with standard gearcases. Built around 10W-30 four-stroke oil, this kit includes the essential maintenance components commonly replaced at the 300 hour interval—covering lubrication, cooling, ignition, fuel filtration, and corrosion protection.
Fits:
- 8 HP Carb (209cc) – Serial 0R042475 & up
- 9.9 HP Carb (209cc) – Serial 0R042475 & up
What’s Included in This Kit
- 1x 10W-30 Four-Stroke Engine Oil (Quart)
- 1x Gear Lube (Quart)
- 1x Fuel Filter
- 1x Oil Drain Seal
- 2x Gearcase Drain Seals
- 1x Thermostat
- 1x Thermostat Gasket
- 2x Spark Plugs
- 1x Water Impeller Kit
- 1x Anode
Why This 300 Hour Service Kit Matters
- Complete milestone service: Covers oil, gearcase, cooling, ignition, and fuel filtration components.
- Cooling system refresh: Impeller and thermostat replacement help maintain proper operating temperature.
- Reliable starting and performance: Fresh spark plugs and fuel filter support clean combustion.
- Corrosion protection: New anode helps reduce galvanic corrosion in marine environments.
FAQ
Does this kit fit EFI models?
No. This kit is designed for carbureted 209cc 8 HP and 9.9 HP models 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.
How do I confirm compatibility?
Verify your horsepower, engine type (carbureted 209cc), serial number range, and that your engine uses a standard gearcase before ordering.
Specs & Engine Application
Specs & Engine Application
-
Engine Application
- 9.9 HP Carb (209cc) - 0P325500-1R279944
- 8 HP Carb (209cc) - 0P325500-1R279944
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