Mercury – Quicksilver 816608Q80 Red Wire Spark Plug Wire Kit | MerCruiser 5.7L Inboard & Tow Sports Engines | Thunderbolt IV Ignition | 816608Q80

Overview

Good spark equals good power — and that starts with quality wires. The Quicksilver 816608Q80 Red Wire Spark Plug Wire Kit keeps your MerCruiser 5.7L inboard and tow-sports engine firing clean and strong. Designed for Thunderbolt IV ignition systems (1998–2010), this OEM wire set delivers reliable spark, clean combustion, and the kind of long-term dependability serious boaters expect.

Each wire is cut to the perfect length for your engine’s layout, making routing simple and tidy. The bright red jacket adds a sharp, factory look under the cover while protecting the core from heat, moisture, and vibration.

Key Features

• Purpose: Replaces worn plug wires to restore ignition strength and prevent misfires.
• Fitment: For MerCruiser 5.7L inboard and tow-sports engines using Thunderbolt IV ignition systems (1998–2010).
• Kit Contents: Includes eight red spark plug wires with pre-installed boots at the plug ends.
• Design: Each wire is custom-length for the correct plug reach and clean routing.
• Durability: Built for marine-grade heat, vibration, and corrosion resistance.

Engine & Boat Compatibility

• MerCruiser 5.7L V8 engines (inboard and tow-sports configurations, 1998–2010)
• Thunderbolt IV ignition systems
• Common on ski boats, wake boats, and high-performance inboard cruisers

Performance & Practical Benefits

The 816608Q80 kit brings your ignition system back to life with strong, even spark delivery to every cylinder. The low-resistance wire core ensures full voltage transfer for smooth starts and steady throttle response. You’ll notice cleaner idling, stronger acceleration, and less hesitation under load.

The red insulation isn’t just for looks — it’s marine-tough. It resists cracking and fading from heat or sunlight and seals tightly against moisture and oil. The result? Wires that last longer, perform better, and keep your engine running like new season after season.

Why Buy OEM

Mercury’s OEM ignition wires are made for marine use from the inside out. Each wire is tested for proper resistance, insulation integrity, and heat endurance to meet Mercury’s exact standards. Aftermarket wire sets may be cheaper, but they rarely match the correct lengths or materials that marine conditions demand.

A genuine Quicksilver wire kit gives you peace of mind — exact fit, tested durability, and factory performance. It’s what your engine was built to run with.

FAQ

Q1: What engines fit the Quicksilver 816608Q80 kit?
A: It’s built for MerCruiser 5.7L inboard and tow-sports engines with Thunderbolt IV ignition systems (1998–2010).

Q2: How many wires come in the kit?
A: The kit includes eight red spark plug wires, all pre-fitted with spark plug boots.

Q3: Can these be used in saltwater?
A: Yes. The insulation and terminals are corrosion-resistant and designed for marine environments.

Q4: Is installation difficult?
A: No. The wires are pre-cut and labeled for a simple one-for-one replacement.

Q5: Why choose OEM wires?
A: OEM wires fit perfectly, last longer, and maintain the proper resistance your ignition system needs for top performance.