Re: Iridium spark plugs running lean?

Posted by MarkPBG on
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Iridium-spark-plugs-running-lean-tp4043769p4043790.html

If the ash is light grey (almost white) then that is normal....even as shown on NGK's website...
http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

If you were running hot, you would, in addition to the whitish ash, see the porcelain beginning to blister, and you would also notice slight wear on the electrode. The iridium plugs have sharp edges on the electrodes....if they've rounded off more than just an almost imperceptible bit, then you may be running hot. The center electrode will become rounded with overheating.