Mercury – QL78V Spark Plug (4-Pack) | Ignition Component | Copper Core & Ceramic | Part Number 896329838

Overview

There’s something incredibly reassuring about an engine that fires to life without hesitation especially when you’ve got a long day on the water ahead of you. The Quicksilver QL78V Spark Plug brings that confidence back to your Mercury Marine engine. It’s one of those small parts that quietly influences every moment on the water: the smooth rumble as you pull away from the dock, the crisp response when you push the throttle, and the steady reliability you feel during long runs across open water. Installing a fresh set of these plugs feels like giving your engine a deep breath of clean air and you’ll notice the difference the very next time you turn the key.

Key Features

• Resistor-style spark plug designed to reduce radio frequency interference (RFI)
• Copper core electrode for strong heat conductivity and long-lasting durability.
• High-strength ceramic insulator for stability and efficient heat transfer
• Engineered to meet Mercury Marine OEM ignition specifications
• Sold as a pack of four for complete multi-cylinder replacement.

Engine & Boat Compatibility.

• Fits select Mercury and Force engines requiring QL78V spark plugs
• Suitable for TwoStroke outboards and specific marine ignition systems
• Common on fishing boats, lightweight skiffs, pontoons, center consoles, and runabouts
• Always verify fitment with your engine’s owner’s manual for exact compatibility

Performance & Practical Benefits

A healthy spark plug affects every part of the engine’s personality. With the QL78V installed, starts become quicker and cleaner none of the stumbling or extended cranking that comes with worn plugs. Under throttle, this plug helps deliver a smooth, consistent spark that supports cleaner combustion, steadier response, and stronger mid-range power.

The copper core electrode shines in the marine environment because it dissipates heat quickly, allowing the plug to maintain the right temperature even during long periods of trolling or extended idle. This reduces the likelihood of fouling, especially in engines that see a lot of slow-speed maneuvering around docks, shorelines, or fishing grounds.

Because this plug is a resistor type, it also helps keep your onboard electronics happy. Your radio, sonar, GPS, and gauges stay clearer and more stable without electrical interference something you appreciate most when conditions change quickly and you need your instruments to be trustworthy.

When used as a complete set, these spark plugs restore a sense of balance to your engine. The idle smooths out, throttle transitions feel more predictable, and the overall sound and vibration of the motor become more controlled. It’s the kind of improvement you can feel in your hands on the wheel and hear in the tone of the engine.

Why Buy OEM

Ignition parts are precision components, and using the exact plug Mercury recommends makes a noticeable difference. OEM plugs match the engine’s timing needs, heat range, and spark characteristics. Aftermarket options may look similar, but small variations in construction can lead to rough running, misfires, or decreased fuel efficiency. A set of QL78V plugs ensures your engine fires cleanly, runs smoothly, and performs exactly as Mercury designed it to. It’s a practical choice that seasoned boaters trust because it simply works.

FAQ

Q1: Which engines does the QL78V spark plug fit?

It fits select Mercury and Force engines that specify QL78V in the owner’s manual.

Q2: What makes this OEM plug better than aftermarket versions?

It meets Mercury’s precise ignition specifications, giving you better heat management, spark stability, and long-term reliability.

Q3: How do I confirm this is the correct plug?

Check your engine manual if QL78V or part number 896329838 is listed, this is the right plug.

Q4: Can this spark plug be used in both saltwater and freshwater?

Yes. Its ceramic and copper-core materials are built to withstand true marine conditions.

Q5: Is installation easy for most boat owners?

Yes most owners can install the full set with a standard spark plug socket.