The NGK LKAR7C-9 is an original resistor spark plug developed for modern, high-performance 4-stroke outboard engines. It is used in, among others, newer Mercury and Mariner V6 and V8 engines, where precise ignition and efficient combustion are essential for engine performance and reliability.
The spark plug has a long 26.5 mm M12 thread, a 14 mm hex size, and a spark plug gap of 0.9 mm. The integrated 5 kΩ resistor reduces electrical noise, which is particularly relevant in modern boats with sensitive electronics, instrumentation, and navigation equipment.
NGK specifies the LKAR7C-9 for a range of newer Mercury engines. This includes, among others, the Mercury 300 HP 4.6L V8 Pro XS, Mercury Racing 200 APX, 250R and 300R, as well as other V6/V8 applications. Mercury also specifies the LKAR7C-9 with a 0.9 mm gap for these engines.
Always check your engine model, serial number, and manufacturer's specifications before ordering, as applications may vary between engine sizes and model years.
Key features
- Original NGK spark plug
- Developed for modern marine gasoline engines
- Integrated 5 kΩ resistor
- Reduces electrical ignition noise
- Spark plug gap of 0.9 mm
- Long 26.5 mm thread
- Compact 14 mm hex size
- NGK heat range 7
- Suitable for newer Mercury and Mariner V6/V8 outboard engines
- Used for, among others, Mercury Pro XS and Racing models
