Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 25W-40 Synthetic Blend - 8M0120837 - S/N 0R042475 & Above
Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 25W-40 Synthetic Blend - 8M0120837 - S/N 0R042475 & Above
Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 25W-40 Synthetic Blend - 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
Stay on schedule with a complete 300 hour service kit for Mercury 8 HP and 9.9 HP carbureted (209cc) four-stroke outboards equipped with standard gearcases. Built around 25W-40 synthetic blend four-stroke oil, this kit includes the core service items plus the cooling, ignition, and sealing components commonly addressed at the 300 hour interval. It is a simple way to refresh critical systems and keep your small outboard starting easily and running reliably.
Fits:
- 8 HP Carb (209cc) – Serial 0R042475 & up
- 9.9 HP Carb (209cc) – Serial 0R042475 & up
What’s Included in This Kit
- 1x 25W-40 Synthetic Blend 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
- Milestone service coverage: Combines fluids, filter, seals, and wear items in one kit so nothing gets missed.
- Cooling system refresh: Thermostat and impeller service helps support proper water flow and stable operating temperature.
- Reliable running: New spark plugs and fuel filtration support clean combustion and dependable starting.
- Corrosion protection: Includes an anode to help reduce galvanic corrosion in marine environments.
FAQ
Does this kit fit EFI models?
No. This kit is intended for carbureted 209cc 8 HP and 9.9 HP four-stroke 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 this kit matches my outboard?
Verify your engine is an 8 HP or 9.9 HP carbureted (209cc) model, falls within the listed serial range, and 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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Reviews
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