Spark Plug

A spark plug is an electrical device that fits into the cylinder head of some internal combustion engine and ignites compressed fuels as such aerosol, gasoline, ethanol and liquefied petroleum gas by means of an electric spark.


Spark plugs have an insulated central electrode which is connected by a heavily insulated wire to an ignition coil or magneto circuit on the outside, forming, with a grounded terminal on the base of the plug, a spark gap inside the cylinder. Picture below shows part of spark plug:-

Diagram 1: Single-ground spark plug

How Do You Adjust Spark Plug Gap?

1. Check the owner's manual for your car (or any appliance with spark plugs) to find out the recommended gap setting.
2. Use a gap tool to check the gap of the spark plug. Slip the tool between the ground electrode and center electrode. The gap tool should fit snugly at the recommended gap width indicated on the tool
3. Push the tool between the electrodes a few times to ensure proper gap. If the gap is too wide, push the ground electrode firmly against a flat surface to narrow the gap and then check again with the gap tool.

 

Resource: e-How, NGK SPARK PLUG, 

Step 4

Use a gap tool to check the gap of the spark plug. Slip the tool between the ground electrode and center electrode. The gap tool should fit snugly at the recommended gap width indicated on the tool.

Step 5

Push the tool between the electrodes a few times to ensure proper gap. If the gap is too wide, push the ground electrode firmly against a flat surface to narrow the gap and then check again with the gap tool.

Read more: How to Gap Spark Plugs | eHow.com http://www.ehow.com/how_2213428_gap-spark-plugs.html#ixzz0sieBdL00