NGK Spark Plug Stock # 6987

The NGK Spark Plug Stock # 6987 (model ZFR6F-11G) is a premium OEM-quality resistor spark plug engineered for reliable ignition performance across a wide range of small and mid-sized gasoline engines. Featuring a 14mm thread diameter and 0.749-inch reach, this plug delivers consistent cold-start performance and stable combustion across varying load conditions, making it ideal for general automotive, small equipment, and powersports applications where proven spark reliability is non-negotiable.

The gasket seat design ensures a proper seal at the cylinder head, eliminating the need for additional compression washers and simplifying installation. The resistor element suppresses electromagnetic interference (EMI), protecting sensitive engine electronics and radio systems from spark-induced noise—a critical specification for modern vehicles and equipment with integrated circuit boards. The ZFR6F-11G maintains consistent gap and firing characteristics across extended service intervals, reducing fouling and misfires compared to lower-tier alternatives.

NGK's market position in OEM supply and aftermarket performance makes this plug a go-to choice for engine builders, service technicians, and equipment operators who prioritize ignition dependability. The 6987 stock number is widely recognized across automotive and powersports sectors, ensuring compatibility confirmation is straightforward. Whether restoring vintage engines, maintaining fleet equipment, or upgrading spark plug performance on modified powerplants, this resistor plug provides the thermal range and electrical stability expected from NGK's engineering standards.