NGK 4548 Spark Plug

NGK CR9EK Spark Plug for Reliable Ignition

The NGK Standard Spark Plug 4548 is built for consistent ignition performance in a wide range of domestic and import applications. This NGK CR9EK spark plug uses a copper center electrode with nickel tip materials and a nickel ground electrode design to support stable spark delivery and dependable combustion.

NGK’s Standard Spark Plug line is focused on OE-style replacement value, with the manufacturing consistency and application coverage expected from a long-established ignition specialist. For drivers searching for an NGK CR9EK spark plug, part number 4548, this plug is a direct-service ignition component for vehicles that call for the CR9EK specification.

Key Features

• NGK Standard Spark Plug, part number 4548
• CR9EK configuration with 5 kOhm resistance
• Copper center electrode core for dependable conductivity
• Nickel center and ground electrode tip materials
• Standard ground electrode design with two ground electrodes
• Pre-gapped at .028 inch
• 10 mm thread diameter, .75 inch reach, flat seat
• 5/8 inch hex size and stud terminal type
• Manufacturer heat range 9

Detailed Description

NGK 4548 is a standard replacement spark plug engineered to match the CR9EK specification. Its copper core and nickel electrode construction are selected for steady ignition performance, while the 5 kOhm resistance helps control electrical noise in the ignition system. The flat seat, .75 inch reach, and 10 mm thread diameter make this plug suitable for engines that require this exact fitment profile. If you are servicing an NGK CR9EK application, part number 4548 provides the correct OE-style format for routine ignition maintenance.

This spark plug is commonly searched for by drivers and technicians working on motorcycle and powersports applications, including Honda and Yamaha models that specify the CR9EK design. It is also a relevant search term for NGK 4548 replacement needs when matching the original plug specification matters.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent spark delivery
• Misfire conditions related to degraded electrode surfaces
• Reduced throttle response from weak ignition performance
• Maintenance replacement for CR9EK-specified ignition systems

Installation Notes and Tips

Verify the engine calls for NGK CR9EK / 4548 before installation. Confirm thread diameter, reach, seat type, and pre-gap specification against the service manual for the exact application. Use proper spark plug socket clearance for the 5/8 inch hex, and inspect the ignition coil, plug wire, or boot condition during service. For fitment searches, this part is commonly referenced for CR9EK applications on Honda and Yamaha models.

Quality Assurance

NGK is a long-established OE supplier with broad coverage across automotive, motorcycle, marine, and small engine applications. The 4548 spark plug is produced to support original-equipment standards for durability and operational consistency.

This part cross-references AMS Automotive 4155 for the same application.