Before installing your spark plugs it is wise to confirm the gap size is set correctly. Use a feeler gauge to check for the correct setting, the blade should be a light sliding fit between the electrodes. Gaps can be inadvertently adjusted in transit or during fitting. The correct feeler gauge may be a slightly tighter fit than expected for a brand new plug due to slight edges to electrodes caused by the manufacturing process.
Laser Tools 2483 Offset feeler gauge (12) Learn More