Mercury – Drain Screw | 25HP–40HP TwoStroke Outboards | Precision Fit | 8542464

Overview

Sometimes, it’s the smallest parts that keep your engine running its best. The Mercury 8542464 Drain Screw is one of those unsung heroes — a simple yet essential component that helps keep your carburetor clean, tight, and properly maintained. Designed for Mercury 25HP–40HP TwoStroke outboards, this drain screw provides a perfect seal every time, ensuring smooth maintenance and preventing leaks or air intrusion in your fuel system.

Whether you’re doing a seasonal carburetor service or prepping your motor for storage, you’ll appreciate the precision fit and quality craftsmanship that only a genuine Mercury OEM part can deliver. It’s a small piece of hardware that helps your engine start cleanly, idle smoothly, and stay reliable all season long.

Key Features

• Genuine Mercury Marine drain screw designed for carburetor repair and upkeep
• Fits Mercury 25HP–40HP TwoStroke outboards
• Includes one drain screw and one O-ring for a complete seal
• Provides tight, leak-free performance for reliable fuel system maintenance
• Made from corrosion-resistant, marine-grade materials for lasting durability
• Precision-machined threads ensure smooth installation and secure fit
• Meets Mercury OEM manufacturing standards for performance and longevity

Engine & Boat Compatibility

• Designed for Mercury 25HP–40HP TwoStroke outboards
• Compatible with various Mercury and Mariner carbureted engines within this range
• Commonly used on runabouts, pontoons, skiffs, fishing boats, and utility craft
• Works in freshwater and saltwater environments
• Perfect for routine maintenance, fuel system servicing, and carb rebuilds

Performance & Practical Benefits

When you’re working on your Mercury outboard, every component you touch should inspire confidence — and that’s what you’ll get with the Mercury 8542464 Drain Screw. It’s engineered to deliver a secure, reliable seal on your carburetor drain, so you can remove old fuel or prep your system for maintenance without worry. The included O-ring compresses perfectly, eliminating leaks and maintaining consistent pressure even through temperature changes and vibration.

The result? A tighter, cleaner, and more efficient carburetor. You’ll notice smoother starts, consistent idling, and improved reliability over time — all because the fuel system remains properly sealed and protected. The drain screw’s corrosion-resistant construction ensures it won’t seize, strip, or degrade under harsh marine conditions. Whether you run your boat on saltwater bays or inland lakes, this part holds up against the elements.

Installation is quick and simple. With just a few turns of a wrench, you can have it in place and ready to perform. It’s the kind of small maintenance detail that seasoned boaters appreciate — because they know it’s the little things that keep big engines running strong.

Why Buy OEM

A genuine Mercury Marine part like the 8542464 Drain Screw ensures a precise fit and long-lasting reliability you can’t always count on from aftermarket parts. Mercury’s OEM hardware is engineered with exact tolerances and materials that meet the brand’s rigorous marine testing standards. That means no stripped threads, no weak metals, and no unexpected failures.

Aftermarket substitutes might look similar, but they rarely match Mercury’s quality or precision. In a marine environment, even a small deviation can lead to leaks, corrosion, or long-term performance issues. With OEM, you’re not just replacing a part — you’re maintaining your engine’s integrity and protecting your investment.

It’s a smart, simple upgrade that keeps your Mercury running the way it was designed to — smooth, secure, and dependable every time you turn the key.

FAQ

Q1: Which Mercury engines or systems does the Drain Screw fit?

It fits Mercury 25HP–40HP TwoStroke outboards, providing an exact OEM replacement for factory-installed components.

Q2: What makes this part different from aftermarket alternatives?

Mercury’s OEM design features precise threading, premium materials, and a corrosion-resistant finish that ensures lasting reliability.

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

Check your owner’s or service manual for part number 8542464 or match your engine model and horsepower range.

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

Yes — it’s made from marine-grade materials that withstand corrosion in both environments.

Q5: Is installation straightforward for most boat owners?

Absolutely. Installation is simple and requires only basic hand tools. The included O-ring makes sealing quick and secure.