Description

Mercury MerCruiser / Quicksilver NGK Spark Plug – ITR4A15 (8M0204739)

Maintain strong ignition performance with the genuine Mercury Marine / Quicksilver 8M0204739 NGK ITR4A15 Laser Iridium Spark Plug. This OEM spark plug is designed for select MerCruiser V6 and V8 engines, delivering reliable ignition, improved combustion efficiency, and long service life in demanding marine environments.

The Laser Iridium center electrode provides precise spark and exceptional durability, while the copper core and ceramic insulator help dissipate heat and maintain consistent engine performance.

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Key Features

• Genuine Mercury / Quicksilver OEM NGK spark plug

• Laser Iridium electrode for long service life and consistent spark

• Copper core improves heat dissipation and combustion efficiency

• Corrosion-resistant construction for marine environments

• Pre-gapped to manufacturer specifications for easy installation

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Part Details

• OEM Part Number: 8M0204739

• NGK Model: ITR4A15 (Stock No. 5599)

• Product Type: Iridium spark plugSuperseded / Cross-Reference

• 4 pack

This plug replaces earlier Mercury part numbers including:

• 884019

• 884019001

• 8M2018369

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Compatible Mercury MerCruiser Engines

Commonly used on MerCruiser MPI sterndrive and inboard engines, including:

• 4.3L V6 MPI engines

• 5.0L V8 MPI engines

• 5.7L V8 MPI engines

• 6.2L V8 MPI engines

These engines are typically equipped with ECM 555 ignition systems in many 2001+ applications.

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Performance Benefits

Iridium spark plugs produce a stronger and more stable spark, which can improve engine starting, maintain smoother idle, and provide more efficient combustion across the RPM range.

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Important Compatibility Note

Spark plug type and heat range vary by engine model, ignition system, and serial number range. Always verify compatibility using the engine serial number or owner’s manual specification before ordering.

Shipping: Ships same or next day for fast Canada wide shipping.