Mercury – Quicksilver 816761Q17 Spark Plug Wire Kit | V8 GM MerCruiser (LH) Engines (305 & 350 CID) | Thunderbolt IV Ignition | 816761Q17

Overview

Your engine’s spark system is its heartbeat — and strong, steady spark is key to dependable power. The Quicksilver 816761Q17 Spark Plug Wire Kit keeps that spark strong in V8 left-hand rotation MerCruiser engines (305 and 350 CID) equipped with Thunderbolt IV ignition systems (1993–2003).

This OEM kit is built for the realities of boating: salt air, vibration, and heat. Each wire is the right length for your setup, with molded boots that lock securely onto the plugs for a tight, moisture-resistant fit. Swap them in and you’ll instantly restore smooth idle, clean acceleration, and confident ignition on every start.

Key Features

• Purpose: Replaces worn or cracked wires to restore full ignition performance and prevent misfires.
• Fitment: For V8 LH (left-hand rotation) GM-based MerCruiser engines (305 & 350 CID) with Thunderbolt IV ignition systems (1993–2003).
• Kit Contents: Complete set of spark plug wires with molded plug-end boots for easy, snug connection.
• Design: Each wire is factory-length for proper routing and tidy installation.
• Marine Durability: Built for heat, moisture, and vibration resistance in demanding marine environments.

Engine & Boat Compatibility

• GM-based V8 MerCruiser LH engines (305 CID and 350 CID)
• Thunderbolt IV ignition systems (1993–2003)
• Common on inboard/outboard cruisers, tow boats, and sport runabouts

Performance & Practical Benefits

The 816761Q17 wire set helps your ignition fire cleaner and stronger, giving smoother idle, quicker starts, and a steady pull at any speed. Each wire’s low-resistance core maintains strong spark energy for complete combustion and efficient fuel burn.

The heavy-duty insulation won’t crack under heat or stiffen over time, while the snug-fitting boots keep out water and corrosion. Installation is simple — replace one wire at a time to keep your firing order intact — and once fitted, you’ll notice the engine running quieter and cleaner.

Why Buy OEM

Mercury’s OEM plug wires are built specifically for marine use — not modified automotive parts. Every Quicksilver wire is tested for correct resistance, flexibility, and temperature tolerance. Aftermarket options often miss on length or insulation quality, leading to early failure or weak spark.

A genuine Quicksilver wire kit means exact fit, consistent performance, and the peace of mind that comes with Mercury’s proven design. It’s the same ignition quality your engine had when it left the factory — just new again.

FAQ

Q1: What engines use the Quicksilver 816761Q17 kit?
A: It fits V8 LH GM-based MerCruiser engines (305 & 350 CID) with Thunderbolt IV ignition systems (1993–2003).

Q2: What’s included in the kit?
A: A complete set of spark plug wires, each with molded plug boots for a precise, weather-tight fit.

Q3: Can I install it myself?
A: Yes. Replace one wire at a time to maintain firing order — it’s a straightforward DIY job.

Q4: Are these wires saltwater-ready?
A: Absolutely. The materials and terminals are corrosion-resistant and built to perform in both salt and freshwater.

Q5: Why OEM over aftermarket?
A: OEM wires guarantee the right length, correct resistance, and long-term marine durability that aftermarket options can’t match.