NGK Spark Plug Stock # 4652

The NGK Spark Plug WR4-1 (Stock #4652) is a premium resistor spark plug engineered for reliable ignition performance across a wide range of small-engine and automotive applications. Designed with NGK's V-Power technology, this spark plug delivers consistent firing characteristics and extended service intervals, making it a trusted OEM-equivalent replacement for routine maintenance and performance-critical engines.

Built with an 18mm threaded connector and 13.7mm reach, the WR4-1 fits directly into standard spark plug sockets without adapter hardware. The tapered seat design ensures precise sealing against the cylinder head, minimizing combustion gas leakage and optimizing compression retention. The resistor element built into the plug suppresses radio frequency interference (RFI), protecting sensitive engine electronics and reducing electromagnetic noise—a critical consideration in marine, powersports, and automotive environments where multiple ignition systems operate in close proximity.

This spark plug serves small-displacement engines, lawn equipment, marine outboards, ATVs, utility vehicles, and compact automotive engines where OEM specifications call for standard-heat-range, resistor-type plugs. NGK's manufacturing consistency ensures proper electrode gap, ceramic insulator durability, and corrosion resistance across varied operating temperatures and fuel types. Users replacing factory plugs find this specification maintains original engine timing curves and fuel efficiency without modification.

NGK spark plugs are recognized globally for cold-start reliability, fouling resistance, and long-term electrode wear characteristics. The WR4-1 represents a direct replacement strategy for equipment owners prioritizing engine longevity and consistent performance over extended service seasons.