Mercury – MerCruiser Alpha One 300 Hour Maintenance Kit | Precision Sterndrive Service Kit | Marine-Ready Components | 8M0147072

Overview

If you’ve spent any amount of time with an older MerCruiser Alpha One, you know the kind of loyalty those drives inspire. They’re tough, familiar and surprisingly steady when you give them the care they deserve. There’s a quiet confidence that comes from maintaining a drive that has carried families, fishing crews and weekend wanderers across the water for decades. The Mercury Marine part number 8M0147072 300-hour maintenance kit brings that confidence back by giving you everything you need to keep an Alpha One running smooth and dependable — the way it always should.

Key Features

• Complete 300-hour maintenance kit designed for MerCruiser Alpha One sterndrive systems (1984–1990)
• Includes sterndrive install gasket kit, aluminum anode kit, gearcase drain seals, transom repair kit, shift cable kit, water pump impeller kit and gearcase fill and drain screws
• Durable components built for marine use, including corrosion-resistant aluminum anodes
• High-quality seals and gaskets designed for a tight, reliable fit
• Engineered to restore proper cooling, shifting and overall sterndrive function

Engine & Boat Compatibility

• Fits MerCruiser Alpha One sterndrives from 1984 through 1990
• Supports a wide range of Mercury-powered boats including runabouts, cruisers, fishing boats, bowriders and family weekenders
• Ideal for owners maintaining classic sterndrive setups that have seen years of use

Performance & Practical Benefits

There’s something satisfying about servicing an older Alpha One — you can feel the difference when everything is replaced and dialed in properly. A fresh impeller brings back steady water flow. New seals help the drive feel tight and predictable. And a clean shift cable gives you that smooth, confident engagement when you drop into gear at the ramp or idle into a marina.

This kit was designed to bring all of those improvements together in one place. Each component fits the way it should, without forcing or guessing, because it was built for the original Alpha One layout. Corrosion protection improves with the new aluminum anodes, giving you peace of mind when running in saltwater or brackish bays. The gaskets seat firmly, the hardware threads cleanly and everything feels secure when you torque it down. It’s the kind of maintenance that makes a noticeable difference on the next run — quieter operation, steadier handling and fewer unexpected surprises.

Why Buy OEM

With a drive as time-tested as the Alpha One, choosing genuine Mercury Marine parts is more than a preference — it’s smart maintenance. OEM parts match the drive’s original specifications, which means you don’t have to fight with fitment or worry about mismatched tolerances. You’ll get better longevity, easier installation and a drive that performs the way Mercury intended. Aftermarket kits might look similar, but they rarely deliver the same reliability. When fellow boaters ask for real-world advice, the truth is simple: stick with the parts designed for your drive, and you’ll save time and avoid headaches down the road.

FAQ

Q1: Which systems does this maintenance kit fit?

It fits MerCruiser Alpha One sterndrives built between 1984 and 1990.

Q2: Why choose this OEM kit over aftermarket options?

The fitment is exact, the materials are stronger and the components hold up longer in real marine conditions.

Q3: How do I know this is the correct kit for my drive?

If your boat runs a first-generation Alpha One built from 1984–1990, this is the recommended Mercury Marine part number for your 300-hour service.

Q4: Is the kit suitable for saltwater and freshwater use?

Yes — the included aluminum anodes and marine-grade components are engineered for both environments.

Q5: Is installation manageable for most owners?

Most boaters with standard maintenance experience can install it confidently, thanks to the precise OEM fit.