NGK Laser Iridium Spark Plugs for Mercury Optimax V6 (IZFR6J) — Pack of 6, 1.0mm Iridium & Platinum

These NGK Laser Iridium plugs combine a 1.0 mm iridium fine‑wire center electrode with a platinum ground electrode and a 5kΩ resistor to provide dependable combustion and reduced wear in Optimax V6 marine applications. Designed to match OEM dimensions and performance, they replace worn or original equipment plugs on a range of Mercury Optimax models, offering improved longevity and a predictable gap for efficient starting and throttle response.

Which Mercury outboards do these NGK 4462 plugs fit?

NGK 4462 (IZFR6J) plugs are specified for many Mercury Optimax V6 engines across multiple displacements and model names. Before purchase, cross‑check your engine model and serial year to confirm compatibility.

• Compatible with Optimax models including 150XS Pro, DSI 175, Pro XS 175, JP 185, Pro XS 200, 225XS Pro, Sport XS 225, XS 225, 2.5XS 250, Sport XS 250, XS Pro 250, and 250HP variants.
• Intended for 3.0L and 2.5L V6 Optimax configurations listed by Mercury.
• Sold as a quantity of six to cover a full V6 cylinder set.

What are the key technical features and dimensions?

These plugs follow NGK’s Laser Iridium design for a small, durable center electrode and extended projection to optimize flame travel. They meet OE seat, thread, and reach specifications for direct replacement with reliable electrical resistance and heat range selection.

• Thread: 14 mm diameter with 1.25 mm pitch and 19 mm reach (3/4").
• Electrodes: 1.0 mm iridium center, platinum ground; extended projection fine‑wire design.
• Gap: factory set to 0.031" (0.8 mm); resistor: 5 kΩ; heat range: 6.
• Hex size: 5/8" (16 mm); terminal: solid; seat type: gasket.

How do these plugs affect performance and maintenance?

Upgrading or replacing worn plugs with NGK Laser Iridium units helps maintain reliable ignition and consistent combustion, which supports steady starts and smoother operation. Their durable electrode materials resist erosion, extending intervals between changes compared with conventional plugs.

• Iridium fine wire center improves spark focus and longevity versus standard electrodes.
• Platinum ground electrode enhances wear resistance for stable gaps over time.
• Factory gap and OE fit reduce installation errors and tuning needs.
• Torque specs: cast iron 18–25.3 lb·ft, aluminum 18–21.6 lb·ft for correct installation.

Who is this for: Boaters, marine technicians, and owners of compatible Mercury Optimax V6 outboards looking for OEM‑grade replacement spark plugs that prioritize durability and consistent ignition. These NGK 4462 plugs suit routine maintenance schedules and those seeking a direct, reliable swap to restore engine starting, throttle response, and combustion stability without altering ignition systems.