How do I read the color of a spark plug? Look at the firing tip of your spark plug while paying close attention to the condition and color of the ceramic insulator and the metal electrode. Observe the color first. Light tan or gray deposits are normal, and an indication that everything is working well.
Definition of candle. 1  1 : a usually molded or dipped mass of wax or tallow containing a wick that may be burned (as to give light, heat, or scent or for celebration or votive purposes) 2  2 : something resembling a candle in shape or use a sulfur candle for fumigating.
The light from this candle is measured in lumens. The definition of a lumen is the measure of brightness from a light source. An example of a lumen is the 13 lumens of a candle and the 1,200 lumens of a 100 watt light bulb. lumen.