SCHEDULED MAINTENANCE 1-9 3. Check the plug clearance using a plug clearance gauge and if the value is not within the specified values, adjust it by bending the ground clearance. When installing a new spark plug, install it after checking the uniform plug clearance. Clearance L4GC304A 4. Install the spark plug and tighten it to the specified torque. Take care not to over tighten it to prevent cylinder head threads from damage. SPARK PLUG ANALYSIS SPARK PLUG TEST After connecting the spark plug to the high tension cable, con- nect the outer terminal(main body) to the ground and crank the engine. Because the discharging clearance is narrow in the air, only slight spark will arise.
But if the spark plug is defect, spark does not arise because insulation is damaged. Insulation damaged Insulation damaged Insulation damaged L4GC217A Spark plug clearance 0.7 ~ 0.8mm State Contact point is black Contact point is white Description Density of the fuel mixture is thick Lack of air intake Density of the fuel mixture is thin Ignition timing is fast Spark plug is tight Lack of torque