The color of a spark plug’s ignition can provide valuable insights into engine performance. While opinions vary, here are some guidelines:
- Bright Blue Spark: On an automobile ignition system, a bright blue spark is ideal. This color indicates optimal ignition performance. Automobile engines operate under varying conditions, so a strong blue spark is desirable due to their higher compression ratios and transient RPM changes.
- Yellow/Orange Spark: A yellow or orange spark signifies weaker ignition. However, it’s essential to note that spark color alone doesn’t necessarily indicate a bad spark plug. Factors like compression ratio and fuel delivery play a role. In small air-cooled engines, the spark color may differ from automotive engines.
- Reading the Spark Plug: When inspecting spark plugs, look at the tip of the electrode. A good spark plug should have a light brown or tan color. Any other color or mixture of colors could indicate issues, but it doesn’t automatically mean the spark plug is faulty.