Mercury – Quicksilver Distributor Cap Kit | For Marinized GM V8 MerCruiser Engines with Thunderbolt IV & V | 805759Q3

Overview

If your V8 MerCruiser has been running a little rough or struggling to start, it might be time to refresh the ignition system. The Mercury Marine 805759Q3 Quicksilver Distributor Cap Kit makes it easy to get your spark back where it belongs. This kit includes the cap, rotor, and gasket — all built to factory specs for GM-based MerCruiser engines running Thunderbolt IV or V HEI ignition systems. Each piece is tough enough to handle years of heat, moisture, and vibration on the water, giving you the steady spark and confidence your boat deserves.

Key Features

• Purpose: Restores smooth spark delivery for consistent ignition and strong performance.
• Complete Kit: Comes with the distributor cap, rotor, and gasket — everything you need for a proper tune-up.
• Materials: The cap is molded from a PBT/PET composite, made to resist heat, cracking, and warping.
• Contacts: Uses solid brass inserts for better conductivity and corrosion resistance.
• Design: Built to reduce radio frequency interference (RFI), keeping your electronics clear and reliable.

Engine & Boat Compatibility

• Marinized V8 MerCruiser engines built by General Motors
• Works with Thunderbolt IV and Thunderbolt V HEI ignition systems

Performance & Real-World Benefits

The 805759Q3 distributor cap kit is all about bringing back that crisp, reliable spark. Over time, caps and rotors can wear out or corrode, causing misfires, weak spark, or rough idling. Installing this Mercury OEM kit restores strong ignition performance and helps your engine fire up cleanly every time.

Each component is designed to thrive in a marine environment — the cap’s reinforced plastic holds its shape under heat, and the brass terminals deliver solid, consistent contact. The included gasket keeps moisture out, which means no shorting, no sputtering, and no more chasing electrical gremlins.

You’ll feel the difference right away: a smoother idle, quicker starts, and dependable power under throttle.

Why Choose Mercury OEM

The Quicksilver 805759Q3 is a true Mercury Marine kit, not a generic substitute. Many aftermarket caps use cheaper materials that warp or corrode quickly, leading to premature failure. Mercury’s OEM parts are made to exact tolerances and tested in saltwater, high humidity, and extreme heat — the same conditions your boat faces every time you take it out.

It’s the same kit Mercury techs use at the factory and in service bays, built for reliability, fit, and performance that lasts season after season.

FAQ

Q1: What engines does this kit fit?
It fits V8 MerCruiser engines by GM with Thunderbolt IV or V HEI ignition systems.

Q2: What’s included in the kit?
You’ll get the cap, rotor, and gasket, everything you need to replace the old components.

Q3: Why are the terminals brass?
Brass inserts conduct electricity better than aluminum and last longer in marine conditions.

Q4: Is this kit hard to install?
Not at all — it’s a direct-fit OEM part that installs easily with standard tools.

Q5: Why use OEM instead of aftermarket?
Because Mercury OEM parts deliver better fit, longer life, and performance proven in real-world marine conditions.