NGK 7397 TR5IX Iridium IX Spark Plug for Mercury, OMC, Indmar and Marine Power I/O Engines

The NGK 7397 is an NGK Iridium IX spark plug (TR5IX) built for extreme ignitability and exceptional anti-fouling performance. A tapered cut ground electrode improves cold starting, idle stability, and throttle response, while the iridium fine wire center electrode is six times harder wearing than platinum for long, consistent service life. The copper core center electrode delivers superior heat dissipation and conductivity across a broad heat range, translating into outstanding acceleration, higher fuel efficiency, and durability compared to a standard nickel plug.

This spark plug is designed to fit inboard/outboard (I/O) marine engines from Indmar, Marine Power, Mercury, and OMC, as well as a range of automotive gasoline engines from Dodge/Eagle, Ford/Lincoln/Mercury, GM, Jaguar, Mazda, Mercedes-Benz, and Volvo. Always check your engine owner's manual and confirm the plug specified by your engine's original equipment manufacturer before installation, since using an incorrect plug can reduce performance, hurt fuel economy, or damage the engine.

Specifications

• Brand: NGK
• Manufacturer Part Number: 7397
• Type: TR5IX Iridium IX
• Resistance: 5000 ohms
• Ground Electrode Configuration: Standard
• Ground Electrode Core Material: Nickel
• Center Electrode Core Material: Copper
• Center Electrode Tip Material: Iridium
• UPC: 087295173978
• Weight: 0.15 pounds

Fitment

• Indmar I/O engines, 2005-94
• Marine Power I/O engines, 2000-98
• Mercury I/O engines, 2006-00
• OMC I/O engines, 1998-87
• Dodge/Eagle, 1992-88
• Ford/Lincoln/Mercury, 2012-74
• GM, 2014-75
• Jaguar, 1988-77
• Mazda, 2009-94
• Mercedes-Benz, 1993-84
• Volvo, 1990-76

Replaces (OEM)

No OEM cross-reference numbers are listed for this part.

Frequently Asked Questions

What engines does the NGK 7397 spark plug fit? The NGK 7397 (TR5IX) is designed to fit I/O marine engines from Indmar (2005-94), Marine Power (2000-98), Mercury (2006-00), and OMC (1998-87), as well as automotive engines from Dodge/Eagle, Ford/Lincoln/Mercury, GM, Jaguar, Mazda, Mercedes-Benz, and Volvo across the listed year ranges.

Is the NGK 7397 an iridium spark plug? Yes, the 7397 is an NGK Iridium IX plug (TR5IX) with an iridium fine wire center electrode that is six times harder wearing than platinum, paired with a copper core for improved heat dissipation and conductivity.

What is the electrical resistance of this spark plug? The NGK 7397 has a resistance of 5000 ohms.

What materials make up the electrodes on the 7397 plug? The center electrode has a copper core with an iridium tip, and the ground electrode has a nickel core, in a standard ground configuration.

Does the tapered ground electrode make a real difference? On the NGK 7397, the tapered cut ground electrode is designed to improve cold starting, idle stability, and throttle response compared to a conventional ground electrode design.

How much does the NGK 7397 spark plug weigh? This spark plug weighs 0.15 pounds.

What is the UPC for the NGK 7397 spark plug? The UPC for the NGK 7397 (TR5IX) spark plug is 087295173978.

How many spark plugs come in this listing? The NGK 7397 is sold as a single spark plug.

Are there OEM cross-reference numbers for the NGK 7397? No OEM cross-reference or Replaces numbers are listed for the NGK 7397 (TR5IX) spark plug.

How does the 7397 Iridium IX plug compare to a standard nickel plug? The NGK 7397's iridium center electrode tip and copper core provide better heat dissipation, conductivity, and durability than a standard nickel plug, along with improved acceleration and fuel efficiency.

Should I confirm fitment before ordering the 7397 plug? Yes, check your engine and maintenance manual for the correct spark plug and use only the plug recommended by your engine's original equipment manufacturer, since an incorrect plug can reduce performance, hurt fuel economy, or damage the engine.