NGK 4677 Spark Plug

NGK BR9ECS Standard Spark Plug

NGK BR9ECS is a standard spark plug built for reliable ignition performance in a wide range of domestic and import applications. It uses a copper center electrode core, nickel center electrode tip, and nickel ground electrode materials to support consistent spark delivery and stable combustion.

As part of the NGK Standard Spark Plug line, this plug reflects NGK’s OE-focused manufacturing approach for drivers who want a direct-replacement ignition component with proven dimensions and heat range selection. It is a practical choice for motorcycle, marine, and small engine service as well as automotive use where the specified BR9ECS design is required.

Key Features

• Part number BR9ECS / stock number 4677
• Resistance: 5000 ohms
• Manufacturer heat range: 9
• Pre-gap size: .032
• 14.00 mm thread diameter with .75 reach
• Flat seat design
• Low-angle ground electrode tip with slant ground configuration
• Copper core center electrode with nickel tip material
• Nickel ground electrode core material with 1 ground electrode
• Non-removable nut terminal and 13/16 hex size

Detailed Description

The NGK 4677 spark plug is engineered around the BR9ECS specification, making it a direct-match replacement where that part number is called for. Its copper core helps support efficient heat transfer, while the nickel electrode materials and 5000-ohm resistance are selected to maintain dependable ignition characteristics under normal operating conditions. For buyers searching for NGK BR9ECS spark plug, NGK 4677, or a standard spark plug for motorcycle and small engine service, this plug provides the core dimensions and electrode design needed for proper fit and function. It is also a relevant search match for select Honda Civic and Toyota Corolla ignition service when those vehicles call for the BR9ECS specification.

This part cross-references Autolite 4173 for the same application.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Misfire conditions from weak or inconsistent spark output
• Rough idle related to degraded ignition performance
• Reduced throttle response from an aging plug
• Service replacement needs for BR9ECS-specified applications

Installation Notes and Tips

Verify the thread diameter, reach, seat type, and heat range against the original plug before installation. Set the gap to .032 if required by the application, and confirm the terminal style matches the ignition lead or coil connection. For best results, install on a cool engine and torque to the vehicle manufacturer’s specification. Search terms such as BR9ECS spark plug replacement, NGK 4677 ignition service, and Honda Civic or Toyota Corolla spark plug replacement can help confirm the correct application before ordering.

Quality Assurance

NGK is a long-established OE supplier with extensive North American and global manufacturing and distribution support. The brand’s focus on original equipment standards and broad vehicle coverage makes this spark plug a dependable OE-style replacement for specified applications.