NGK 4551 Standard Spark Plug BR9HS-10 for 1987-2004 Yamaha Outboards

The NGK 4551 is a standard spark plug built on NGK's proven nickel-alloy design, engineered to deliver reliable ignition performance in Yamaha outboard engines. Carrying NGK's BR9HS-10 plug specification, it is designed for boaters who want dependable, OE-caliber starting and running performance without paying for a premium precious-metal upgrade.

The plug uses a solid copper core for superior heat dissipation and conductivity across a broad heat range, paired with a nickel ground electrode and nickel-tipped center electrode. A high-grade alumina silicate ceramic insulator provides strength and efficient heat transfer, while cold-rolled threads reduce the risk of cross-threading during installation. The shell is treated with a corrosion-resistant trivalent plating, which eliminates the need for anti-seize compound and features corrugated ribs that help prevent flashover.

The NGK 4551 fits Yamaha outboard motors covered by NGK's O/B fitment listing for the BR9HS-10 plug. Always confirm the correct plug against your engine's maintenance manual before installing, since using the wrong plug can reduce performance and fuel economy or damage the engine.

Specifications

• Brand: NGK
• Manufacturer Part Number: 4551
• NGK Plug Designation: BR9HS-10
• Resistance: 5000 Ohm
• Ground Electrode Configuration: Standard
• Ground Electrode Core Material: Nickel
• Center Electrode Core Material: Copper
• Center Electrode Tip Material: Nickel
• Insulator Material: Ceramic (alumina silicate)
• Plating: Trivalent, corrosion-resistant
• Quantity: 1 spark plug per package
• Weight: 0.15 pounds
• UPC: 087295145517

Fitment

• Yamaha Outboard, 2004-1987

Frequently Asked Questions

What engines does the NGK 4551 spark plug fit? The NGK 4551 (BR9HS-10) is designed to fit Yamaha outboard motors covered under NGK's 2004-1987 O/B Yamaha fitment listing.

Is the NGK 4551 the same as the BR9HS-10? Yes, 4551 and BR9HS-10 refer to the same NGK standard spark plug; BR9HS-10 is the plug's technical designation and 4551 is its part number.

What is the electrode material on this spark plug? The NGK 4551 uses a nickel ground electrode, a copper core center electrode, and a nickel center electrode tip.

Is this a resistor-type spark plug? Yes, the NGK 4551 has a resistance rating of 5000 Ohm.

How many spark plugs come in one package? Each package of the NGK 4551 contains 1 spark plug.

What does the NGK 4551 weigh? The NGK 4551 spark plug weighs 0.15 pounds.

Does the NGK 4551 need anti-seize compound during installation? No, the trivalent plating on the NGK 4551 eliminates the need for anti-seize compound, and cold-rolled threads help prevent cross-threading during installation.

What type of insulator does the NGK 4551 use? The NGK 4551 uses a high-grade alumina silicate ceramic insulator for strength and efficient heat transfer.

How does the NGK 4551 compare to NGK's iridium or platinum plugs? The NGK 4551 is a standard nickel-electrode plug built for reliable OE-level performance, rather than the longer-service-interval precious-metal electrodes found in NGK's premium iridium or platinum lines.

Is the NGK 4551 a genuine NGK product? Yes, the NGK 4551 (BR9HS-10) is manufactured by NGK as part of its Standard spark plug lineup.

What ground electrode configuration does the NGK 4551 use? The NGK 4551 uses a Standard ground electrode configuration.

What is the UPC for the NGK 4551 spark plug? The UPC for the NGK 4551 spark plug is 087295145517.