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2-7 Day Delivery
Earn up to 4.5% Back on Purchases
Duties & Taxes Included

2-7 Day Delivery

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2-7 Day Delivery

Estimated 2–7 day delivery based on the shipping method selected at checkout.

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Earn up to 1.5 points for every $1 spent. That’s up to 4.5% back that you can redeem and save on future orders. Excludes engine & lower unit sales.

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Duties & Taxes Included

No surprise fees at delivery. Duties and taxes are calculated and paid at checkout where applicable.

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Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 10W-30 - 8M0120837 - S/N 0R042475 & Above
SKU: PVM00086
$223.47
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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
  • Engine Application
    • 9.9 HP Carb (209cc) - 0P325500-1R279944
    • 8 HP Carb (209cc) - 0P325500-1R279944

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Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 10W-30 - 8M0120837 - S/N 0R042475 & Above
Mercury

Mercury 8/9.9 Complete 300 Hour Service Maintenance Kit Standard Gearcase Only 10W-30 - 8M0120837 - S/N 0R042475 & Above

$223.47

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:

What’s Included in This Kit

Why This 300 Hour Service Kit Matters

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.

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