Mercury – 300 Hour Maintenance Kit | FourStroke EFI Series | Marine-Grade Components | 8M0151470

Overview

If you run a small Mercury FourStroke regularly, you already know how much those engines become part of your routine. They start before sunrise fishing trips, push you across quiet lakes, and help you ease into shore at the end of a long day. When you reach the 300-hour mark, you want a kit that gives you confidence—something that feels like you’re giving your motor the care it deserves. The Mercury 8M0151470 300 Hour Maintenance Kit is built exactly for that moment. It keeps your 9.9 to 20 horsepower EFI FourStroke running smooth, cool, and steady, so every trip feels as dependable as the last.

Key Features

• Complete 300-hour service kit for select Mercury 9.9–20 horsepower FourStroke EFI models
• Includes oil filter, fuel filter, oil drain seal, gearcase seals, thermostat, thermostat gaskets, spark plugs, impeller kit, and unit anodes
• High-capacity filter media for consistent lubrication and fuel delivery
• Electroplated housings designed to withstand corrosion in harsh marine environments
• Convenient, Mercury-engineered package with all required service components

Engine & Boat Compatibility

• Fits Mercury 9.9 horsepower FourStroke EFI engines (serial numbers 1R008146–1R278792)
• Fits Mercury 15–20 horsepower FourStroke EFI engines (serial numbers 0R833820 and above)
• Ideal for small fishing boats, inflatables, dinghies, tenders, jon boats, and lightweight skiffs
• Suitable for both tiller and remote-steering applications

Performance & Practical Benefits

A 300-hour service is more than routine maintenance—it’s a reset button for your engine. This Mercury Marine part refreshes systems that take the most daily wear. The new spark plugs give you crisp ignition. The thermostat and gaskets help your motor maintain a steady temperature even on long runs. The impeller kit restores cooling confidence, especially valuable in shallow or sediment-heavy waters. The anodes step in to protect the engine from electrolysis, extending the life of your lower unit.

On the water, what you’ll notice is simple: everything feels better. Throttle response becomes smooth again, idle settles down, and shifting feels more controlled. You’ll feel that steady, dependable “heartbeat” from the transom—the one that tells you your motor is healthy and ready for whatever the day brings. The kit installs cleanly too. Because every component is designed specifically for these FourStroke EFI models, there’s no guesswork, no forcing parts to fit, and no surprises halfway through the job.

Why Buy OEM

• Genuine Mercury Marine quality designed for precise fit and long life
• Protects your investment with parts engineered for your exact engine
• More reliable than piecing together aftermarket alternatives
• Helps prevent cooling issues, ignition problems, and fuel contamination
• Saves time and money by ensuring everything works right the first time

If you’re the kind of boater who keeps a simple toolkit onboard and prefers equipment you can trust, OEM maintenance kits are the way to go. They help your engine last longer and perform better season after season.

FAQ

Q1: Which engines does this kit fit?

It’s made for Mercury 9.9hp EFI (1R008146–1R278792) and 15–20hp EFI engines (0R833820 and above).

Q2: How is this different from aftermarket kits?

OEM components meet Mercury’s exact specifications for filtration, cooling, and protection—something aftermarket parts can’t guarantee.

Q3: How can I confirm this is the right kit?

Match your serial number to the ranges listed above or refer to your owner’s manual.

Q4: Is it suitable for saltwater use?

Absolutely. The materials and coatings are built to handle both fresh and saltwater conditions.

Q5: Is installation manageable for most owners?

Yes. Most boaters with basic tools and patience can complete a 300-hour service using this kit.