Mercury – 300 Hour Maintenance Kit | 150hp FourStroke Service Series | OEM Replacement Components | 8M0094233

Overview

There’s a certain confidence that comes from a motor that’s been cared for the right way. Not “good enough” cared for—properly serviced, on schedule, with parts you trust. If you run a Mercury 150 horsepower FourStroke, you already know it’s a workhorse. But even workhorses need a reset after a long season of early starts, long runs, and plenty of idle time around docks and sandbars.

This Mercury Marine part makes that big milestone service feel simpler and more doable. Everything you need for the 300-hour maintenance is gathered into one kit, so you’re not piecing it together item by item. You knock it out, button everything up, and head back out with that calm feeling that your engine’s ready for the next stretch.

Key Features

• Complete 300-hour service kit for Mercury 150 horsepower FourStroke outboards
• Designed as a convenient, all-in-one package for routine maintenance
• Includes key service components:
  • Oil filter
  • Fuel filters
  • Gearcase drain seals
  • Spark plugs (four)
  • Thermostat kit
  • Water impeller kit
  • Alternator belt
  • Anodes
• Premium-quality oil and fuel filters with high internal pleat counts for strong filtration
• Heavy-duty electroplated filter housings help resist corrosion
• Mercury Marine part number 8M0094233

Engine & Boat Compatibility

• Fits Mercury 150 horsepower FourStroke outboards with serial number 1B905505 and higher
• Common on bay boats, center consoles, pontoons, bass boats, and family runabouts
• Ideal for engines used in both freshwater and saltwater, especially with frequent weekend use

Performance & Practical Benefits

A 300-hour service is where you bring everything back into balance. Fresh filters help fuel and oil flow cleanly. New spark plugs help the motor fire consistently. A thermostat refresh can help keep operating temperature steady. And the water impeller kit is a big one—cooling is life on an outboard, and a new impeller often brings back that strong, reassuring telltale stream.

What I like about a complete kit is the rhythm of the job. You’re not stopping mid-service because you forgot a seal or realized you needed one more filter. You’ve got what you need, so the work stays clean and confident. When you finish, the engine tends to feel smoother and more predictable—especially at idle and during mid-range cruising where small issues usually show themselves first.

There’s also a long-term benefit that’s hard to put a price on: fewer surprises. Staying ahead of wear items keeps your boat days from turning into troubleshooting days. It helps your 150 horsepower FourStroke stay tight, steady, and ready—whether you’re making a long run across open water or just enjoying a calm afternoon with the family.

Why Buy OEM

For major scheduled service, OEM parts matter. This is a genuine Mercury Marine part kit designed around your specific engine, so the fitment is right and the components match Mercury’s service expectations. That saves time, avoids compatibility headaches, and supports long-term reliability.

Aftermarket bundles can vary in filter quality, sealing surfaces, and overall consistency. With OEM, you’re getting parts meant to work together and perform correctly the first time. My advice to another boater is simple: if you’re going to do the 300-hour service, do it once and do it right.

FAQ Section

Q1: Which Mercury engines or systems does the 300 Hour Maintenance Kit fit?

It fits Mercury 150 horsepower FourStroke outboards with serial number 1B905505 and higher.

Q2: What makes this part different from aftermarket alternatives?

It’s an OEM Mercury Marine part kit with engine-specific components and premium filtration design, built to match Mercury service requirements.

Q3: How do I know if this is the correct replacement for my setup?

Check your outboard model and confirm the serial number is 1B905505 or higher, then match the part number to 8M0094233.

Q4: Can this be used in both saltwater and freshwater applications?

Yes. The kit supports routine service in either environment. In saltwater, anode checks and cooling system care are especially important.

Q5: Is installation straightforward for most boat owners?

Many experienced owners can handle a 300-hour service with the right tools and a service manual. If you’re unsure, a Mercury technician can complete it efficiently.