Quicksilver Spark Plug Wire Kit 816761Q17 for MerCruiser 305/350 V8 LH — Thunderbolt IV OEM-fit marine-grade

Quicksilver 816761Q17 is a complete spark plug wire kit engineered for V8 MerCruiser (305/350 CID) engines with Thunderbolt IV ignition, delivering correct reach and durable marine performance.

This OEM-grade wire set replaces worn or damaged ignition leads on 1993–2003 MerCruiser V8 (LH) engines. Built to Quicksilver standards, the kit includes boots at the spark plug end and is shaped to match factory routing so you get reliable spark delivery, reduced interference, and longevity in a saltwater environment. The design focuses on correct length and secure connections to restore engine efficiency and simplify installation.

How does this wire kit match my MerCruiser V8 ignition layout?

The 816761Q17 kit is made to the exact reach and routing geometry required for LH MerCruiser 305 and 350 CID engines equipped with Thunderbolt IV ignition. That means each lead fits the distance from coil to plug without excess slack or strain, lowering the chance of chafing or misrouting.

• Pre-formed lengths tailored for factory plug locations
• Boots included at the spark plug ends for correct seating
• Designed for Thunderbolt IV ignition timing and coil layout

What materials and construction improve durability in a marine setting?

Quicksilver uses materials and assembly techniques intended to withstand heat, vibration, and moisture typical aboard boats. Insulation and boot compounds resist degradation from oil and salt spray while internal conductors provide consistent spark energy transfer across engine cycles.

• Robust insulation to resist heat and abrasion
• Corrosion-resistant connectors for marine exposure
• Boots that seal the spark plug connection to keep out moisture

Will installing this set improve engine performance or reliability?

Replacing aged or damaged wires with a correct-fit Quicksilver set restores intended ignition timing and reduces misfires caused by leaks or weak conductivity. While it won’t increase horsepower beyond factory specs, it helps the engine run smoothly, start reliably, and maintain consistent firing across cylinders.

• Reduces misfires and rough idling from deteriorated leads
• Helps maintain consistent spark strength under load
• Supports dependable starts in varied temperature and humidity

How easy is it to install the Quicksilver wire kit?

Installation is straightforward when following factory routing and retaining clips: remove one old lead at a time, replace with the matching-length new wire, and seat both ends securely. For best results, inspect boots and terminal seats, apply dielectric grease sparingly if desired, and verify routing avoids heat sources and moving parts.

• Direct-fit lengths minimize trimming or modification
• Swap one wire at a time to preserve firing order
• Follow existing clips and harness paths for clean routing

Who is this for: Boat owners and marine technicians who service MerCruiser V8 (305/350 CID) engines with Thunderbolt IV ignition, and anyone restoring factory ignition reliability on 1993–2003 models. Choose this Quicksilver kit when you want an OEM-level replacement that simplifies installation, resists marine wear, and preserves original ignition geometry without aftermarket guesswork.