Mercury – Seal Flush Plug | Cooling & Maintenance Components | Marine Rubber | 8M0219168

Overview

Every boater knows that small parts can make a big difference, especially when it comes to keeping your engine’s cooling system protected. The Mercury Seal Flush Plug 8M0219168 is one of those quiet essentials you don’t think much about—until the day you really need it. It’s a simple piece, sure, but it’s also the kind of part that gives you peace of mind when you’re rinsing the engine after a long day on the water or prepping for storage. With a secure seal and dependable fit, it lets you focus on the bigger picture: taking care of the engine that takes care of you.

Key Features

• Seals the engine flush port to maintain proper cooling system integrity
• Durable, marine-safe rubber construction
• Designed for consistent sealing in repeated freshwater and saltwater use
• Sized specifically for Mercury outboard flush ports
• Straightforward installation with a snug, reliable fit

Engine & Boat Compatibility

Fits Mercury engines including:

• 75–115hp 2.1L FourStroke (2B094996 & up)
• 135–150hp 3.0L FourStroke (1B905505 & up)
• 175–225hp 3.4L V6 FourStroke (2B529482 & up)
• 200–300hp 4.6L V8 FourStroke and Verado (2B529482 & up)
• 350–425hp 5.7L V10 Verado (3B266064 & up)
• 450R–500R 4.6L V8 Mercury Racing outboards (1E083006 & up)

Common boat types:

• Center consoles
• Offshore fishing boats
• Pontoons and deck boats
• All-purpose family boats and dual-console setups

Performance & Practical Benefits

This small flush plug brings a surprising amount of reassurance to engine maintenance routines. Once installed, it creates a tight, secure seal that helps protect the water passage from debris, backflow and corrosion from repeated exposure. You’ll notice how cleanly it snaps into place, and how it stays put even when the boat takes a few hard bumps or vibrations.

The marine-safe rubber holds its shape over time, resisting cracking and swelling. That means you’re not left dealing with leaks, drips or frustrating water bypass during flushing sessions. Whether you’re rinsing out salt after a fishing run offshore or clearing sediment from a lake adventure, the seal stays steady and reliable. It’s the kind of part that contributes to long-term engine health without ever calling attention to itself—and that’s exactly what you want from a component like this.

Why Buy OEM

Buying a genuine Mercury Marine part is about removing uncertainty. With OEM fitment, there’s no guesswork, no trimming, no second attempts to make the plug seat properly. Mercury engineers design this flush plug specifically for the brand’s cooling systems, ensuring the right pressure retention and the right material response.

Aftermarket versions may look similar, but the stiffness, elasticity or sealing surface often isn’t quite right. Over time, that leads to air leaks or compromised flushing efficiency. With the Mercury 8M0219168 part number, you’re getting the seal the engine was built around—reliable, long-lasting and made for the marine environment.

FAQ

Q1: Which Mercury engines does this plug fit?

It fits a wide range from 75hp FourStroke models through 425hp V10 Verado and select Racing platforms.

Q2: Why choose OEM over aftermarket?

The OEM material blend maintains proper sealing pressure and longevity, something many aftermarket plugs struggle to match.

Q3: How do I confirm it's the correct replacement?

Match your serial number to the compatibility list or compare the existing plug shape and diameter.

Q4: Can it be used in both freshwater and saltwater?

Yes—its marine-safe rubber is built to withstand both environments.

Q5: Is installation easy?

Very. It presses securely into place and removes just as easily when it’s time to flush the engine again.