Mercury – Cap and Rotor Kit | For GM V8 MerCruiser Engines with Thunderbolt IV & V Systems | 805759T3

Overview

A strong, reliable spark is the backbone of every good running engine. The Mercury Marine 805759T3 Cap and Rotor Kit restores smooth ignition performance to your GM-based V8 MerCruiser equipped with Thunderbolt IV or V HEI ignition systems. Built with durable marine-grade materials, this kit is designed to handle the heat, vibration, and humidity that come with boating. With precision-molded components and corrosion-resistant brass contacts, it delivers consistent spark timing — helping your engine fire clean, idle smooth, and perform at its best.

Key Features

• Purpose: Replaces worn ignition components to restore smooth spark delivery.
• Design: Includes a distributor cap, rotor, and gasket built to OEM standards.
• Construction: Molded from a PBT/PET composite for strength, stiffness, and heat resistance.
• Performance: Coated brass rotor blade ensures clean electrical contact and long service life.
• Protection: Designed to minimize RFI interference with onboard electronics and sensors.

Engine & Boat Compatibility

• GM-built V8 MerCruiser engines using Thunderbolt IV and Thunderbolt V HEI ignition systems

Performance & Real-World Benefits

The 805759T3 Cap and Rotor Kit keeps your ignition system running like it should. Over time, corrosion, arcing, and heat can wear down the distributor components, leading to misfires, rough idle, or weak throttle response. Installing this Mercury OEM kit restores the spark timing and consistency your engine was built for.

The high-strength housing stays rigid under marine heat, while the brass rotor and terminals provide excellent conductivity and resistance to corrosion. With fresh components, you’ll notice easier starts, smoother acceleration, and a steady idle — exactly what you want when you turn the key and head out on the water.

Why Choose Mercury OEM

The Mercury 805759T3 is a genuine Mercury Marine part, made to withstand the demanding conditions that aftermarket parts often can’t. While generic kits may fit, they often use inferior materials that warp or fail early, especially in marine environments.

Mercury’s OEM ignition components are precision-tested to deliver the same spark quality and longevity as the originals installed in new MerCruiser engines. It’s the same kit trusted by factory technicians to keep engines running smooth, reliable, and strong.

FAQ

Q1: What’s included in this kit?
It includes a distributor cap, coated brass rotor blade, and gasket — everything needed for a complete replacement.

Q2: What engines does it fit?
It’s made for GM-built V8 MerCruiser engines with Thunderbolt IV or V HEI ignition systems.

Q3: Why replace the cap and rotor together?
Replacing both ensures consistent spark timing and strong, even ignition across all cylinders.

Q4: How long do these parts last?
They’re built from marine-grade composites and brass, lasting several seasons under normal marine use.

Q5: Why OEM over aftermarket?
Because Mercury OEM parts are built for precise fit, lasting durability, and corrosion resistance — crucial for marine reliability.