Mercury – Gray Spark Plug Wire/Lead | Ignition System Component | Durable Marine-Grade Construction | 857124A1

Overview
Every boater knows that a smooth-running engine starts long before the key turns—it begins with a clean, strong spark. When you’re heading out before sunrise or easing back toward the dock at the end of a long day, you want to trust that your ignition system won’t miss a beat. That’s why a dependable spark plug wire matters more than most folks realize. The Mercury Marine part number 857124A1 Gray Spark Plug Wire/Lead delivers the kind of steady, confident performance that keeps a two-stroke feeling lively and responsive, season after season.

Key Features

• Delivers consistent spark transfer between ignition coil and spark plug

• Features marine-grade insulation to protect against heat, moisture, and vibration

• Includes molded plug boot on one end and coil boot on the other for secure connections

• Designed for long-lasting flexibility and a tight, clean fit

• Suitable for a wide range of Mercury and Mariner outboards from 30 to 250 horsepower

Engine & Boat Compatibility

• Works with Mercury and Mariner 30–250 horsepower 2-stroke outboards

• Compatible with 2-, 3-, and 4-cylinder EFI, carbureted, and jet-drive models

• Fits XR2, JetDrive, and SportJet engines from 120–240 horsepower

• Ideal for fishing boats, pontoons, offshore skiffs, aluminum rigs, jet boats, and family runabouts

Performance & Practical Benefits
A good spark plug wire does more than move electricity—it shapes the way your engine behaves. With the 857124A1 installed, you’ll feel the difference in every startup. The spark hits with a firm, steady pulse that helps the engine fire quickly, even on cooler mornings or after long periods of sitting. Once running, the wire keeps ignition timing smooth and predictable, cutting down on misfires, hesitation, and the subtle inconsistencies that can make an outboard feel tired.

The marine-grade insulation resists heat, moisture, and the constant vibration that comes with life on the water. That means no brittle cracking, no loose boots sliding off, and no unexpected interruptions just when you need the power most. The connection points fit tightly and securely, giving you that satisfying “click” that lets you know everything is seated exactly right. Installation is simple, requiring only basic tools and a few minutes of attention.

What you really gain is peace of mind. With a fresh, properly engineered spark plug lead, the engine feels more confident at idle, steadier under load, and more responsive when you throttle up. It’s one of those upgrades that doesn’t look dramatic on the workbench but transforms how the engine feels on the water.

Why Buy OEM
Ignition components may look similar across brands, but performance tells the real story. A genuine Mercury Marine part like the 857124A1 uses the correct wire core, insulation thickness, and boot design to deliver reliable, balanced spark—something aftermarket versions often struggle to match. OEM parts fit right the first time, last longer, and handle the harsh marine environment far better. If you’re looking for a practical, dependable choice that keeps your outboard running strong, sticking with Mercury OEM is the smart move.

FAQ

Q1: Which engines does the Mercury 857124A1 Spark Plug Wire fit?
It fits Mercury and Mariner 30–250 horsepower 2-stroke outboards, including EFI, carbureted, jet-drive, XR2, and SportJet models.

Q2: What makes this wire better than aftermarket alternatives?
Mercury’s marine-grade insulation, precise boot molding, and correct electrical resistance ensure cleaner spark delivery and longer life.

Q3: How do I know if this is the correct replacement?
Match your owner's or service manual to part number 857124A1 for accurate fitment.

Q4: Can this spark plug wire be used in both freshwater and saltwater?
Yes. It’s built to withstand moisture, heat, and corrosion in both environments.

Q5: Is installation simple for most boat owners?
Absolutely. With basic tools and careful seating of both boots, installation is quick and straightforward.