Mercury – Quicksilver 816761Q3 Spark Plug Wire Kit | V8 GM MerCruiser (RH) Engines (305 & 350 CID) | Thunderbolt IV Ignition | 816761Q3

Overview

When your engine fires clean and smooth, you can feel the difference right away. The Quicksilver 816761Q3 Spark Plug Wire Kit brings that performance back to your V8 right-hand rotation MerCruiser engine (305 and 350 CID) equipped with Thunderbolt IV ignition systems (1981–1993).

This OEM kit includes a full set of plug wires built to factory specifications — the right length, resistance, and fit for your motor. Each wire features marine-grade insulation to handle the heat, vibration, and moisture that come with boating life. Swap them in, and your MerCruiser will fire stronger, idle smoother, and run more efficiently.

Key Features

• Purpose: Replaces aging or damaged wires to restore proper ignition and spark strength.
• Fitment: For V8 RH (right-hand rotation) GM-based MerCruiser engines (305 & 350 CID) with Thunderbolt IV ignition systems (1981–1993).
• Kit Contents: Complete set of spark plug wires, each pre-fitted with molded boots.
• Design: Factory-length wires ensure clean routing and proper plug reach.
• Durability: Designed for marine heat, vibration, and corrosion resistance.

Engine & Boat Compatibility

• GM-based MerCruiser V8 engines (305 & 350 CID, RH rotation)
• Thunderbolt IV ignition systems (1981–1993)
• Common in cruisers, inboards, and sport runabouts

Performance & Practical Benefits

The 816761Q3 wire kit helps your ignition system deliver strong, consistent voltage to every plug. The result? Easier starts, smoother idle, and clean acceleration across the power band. The low-resistance cores maintain voltage integrity, while the thick insulation prevents arcing even under heat and vibration.

Each wire is molded for a tight seal at both ends, keeping moisture and debris out. Once installed, you’ll enjoy reliable spark energy and confident performance — the kind you can feel every time you throttle up.

Why Buy OEM

Mercury’s OEM ignition components are made for the marine environment — not adapted from automotive designs. Every Quicksilver wire is tested for length, resistance, and flexibility to ensure consistent ignition under harsh marine conditions.

Aftermarket wires can vary in size or material quality, leading to misfires or premature failure. With a genuine Quicksilver wire kit, you’re getting the same durability, fit, and spark performance your engine was designed for — tested and proven in real-world boating conditions.

FAQ

Q1: What engines fit the Quicksilver 816761Q3 kit?
A: It’s designed for V8 right-hand rotation GM-based MerCruiser engines (305 & 350 CID) with Thunderbolt IV ignition systems (1981–1993).

Q2: How many wires are included?
A: The kit includes eight spark plug wires, each cut to the correct factory length.

Q3: Can these wires handle saltwater use?
A: Yes. They’re made from corrosion-resistant materials suitable for both salt and freshwater boats.

Q4: Are they easy to install?
A: Yes. Replace one wire at a time to maintain firing order — no special tools needed.

Q5: Why OEM over aftermarket?
A: OEM wires guarantee the right resistance, length, and marine-ready materials for long-lasting, trouble-free performance.