question on plug reading

As in the article that Craig put in the previous post. As you lean out the motor and raise the combustion temps in the cylinder the cad on the base ring will first start to burn with a greenish color and with small bubbles then light gray then to dark gray. From dark gray they will go frosty. 360 degrees of dark gray is a good strong tuneup and frosty is the ultimate but pushing the envelope. Each change of color will progress around the base ring. You should also watch the color in the threads so you do not burn more than one thread. As far as your question you probably want them to be all evenly 360 degrees dark gray. If you only have one or two dark gray and the rest light gray then I would suggest you increase the size of the port jets to lighten up those dark ones until all appear the same color and then lean it out so they all go dark together. You may need to adjust the port jets again while doing this to keep them even. Reading sparkplugs is far more accurate than reading EGTs.