Why should spark plugs be kept in numbered holes in a tray after removal?

Why should spark plugs be kept in numbered holes in a tray after removal?

• A. Spark plugs tell a good deal about the internal condition of the cylinders from which they were taken, enabling proper action.
• B. To color-code plugs.
• C. To store extra plugs.
• D. To arrange them by size.

Answer: (A)

Keeping spark plugs in numbered holes preserves the link between each plug and its specific cylinder. That way you can compare the condition of plugs from all cylinders and know exactly which cylinder produced what wear, deposits, or overheating signs. The plug condition directly reflects what’s happening in its cylinder, so knowing the cylinder it came from lets you diagnose issues more accurately and decide the proper action—such as adjusting fuel mixture, checking for oil leaks, or inspecting rings and valves. Using a numbered tray avoids mixing up plugs, which would make it hard to tell which cylinder is showing a problem. The other ideas (color-coding, storing extras, or sorting by size) don’t provide that essential cylinder-by-cylinder linkage.

Keeping spark plugs in numbered holes preserves the link between each plug and its specific cylinder. That way you can compare the condition of plugs from all cylinders and know exactly which cylinder produced what wear, deposits, or overheating signs. The plug condition directly reflects what’s happening in its cylinder, so knowing the cylinder it came from lets you diagnose issues more accurately and decide the proper action—such as adjusting fuel mixture, checking for oil leaks, or inspecting rings and valves. Using a numbered tray avoids mixing up plugs, which would make it hard to tell which cylinder is showing a problem. The other ideas (color-coding, storing extras, or sorting by size) don’t provide that essential cylinder-by-cylinder linkage.