The NGK CR8EH-9 Standard Spark Plug (NGK Part No. 5666, MPN 7750) is a reliable, resistor-type plug for petrol engines used in motorcycles, scooters, generators, lawn and garden tools, and compact construction equipment. It uses a copper core with a nickel alloy electrode and a tough ceramic insulator to deliver steady ignition and dependable heat dissipation. By providing a consistent spark, it helps engines start cleanly, idle smoothly, and run efficiently under load. Pre-gapped to 0.9 mm (0.035 in), it is suitable for many small-engine applications where an NGK heat range 8 plug is specified. Made by NGK, it offers a straightforward like-for-like replacement for worn plugs such as CR8EH-9 used on popular small engines, including those found in portable generators and brushcutters.

Key Features:
– Resistor type (R) reduces electrical interference with ignition systems and onboard electronics
– Pre-gapped to 0.9 mm (0.035 in) to speed up fitting; verify and adjust to the equipment maker’s spec if required
– Copper core and nickel alloy electrode for efficient heat transfer and stable spark
– Durable alumina ceramic insulator with ribbing to resist flashover and fouling
– Designed for consistent cold starts, smooth idling, and clean combustion
– Standard form factor for easy installation using a regular spark plug spanner
– Supports engine longevity by helping to prevent misfires and plug fouling
– Suitable for a wide range of small petrol engines in garden, construction, and light industrial machinery

Typical Applications:
Ideal for small four-stroke petrol engines in motorcycles and scooters, portable generators, water pumps, pressure washers, lawn mowers, ride-on mowers, brushcutters/strimmers, hedge trimmers, and compact site equipment where NGK CR8EH-9 is specified. Use as a direct replacement to restore reliable ignition and overall running quality.

Also known as:
Engine spark plug, ignition plug, spark igniter, resistor spark plug, CR8EH9, CR8EH 9, NGK 5666 plug. Often referenced as a standard small-engine plug for maintaining ignition performance and fuel efficiency in a range of petrol-powered tools and machinery.

Alternate Part Numbers:
5666

Product Specifications