[Roadsters] Re. Sparkplug color

[dave]

Tom,

I could make an assumption that the additives in current gasoline, including
ethanol may alter the usual tan color for a good mixture.  One way to
confirm this is to examine a spark plug from your daily driver, if it's a
late model fuel injected engine.  By design, that would have the correct
mixture, and compare the color to the Datsun.



Dave Brisco

East Coast Roadster



-----Original Message-----

From: Tom PRATHER [mailto:tomet9 at sbcglobal.net]

Sent: Tuesday, August 03, 2010 11:15 AM

To: datsun-roadsters at autox.team.ne roadster list

Subject: [Roadsters] Sparkplug Tan vs Gray color



Hi Listers,

                 I have searched the net about reading sparkplug color and
jetting but can never find a definitive answer as to the differences about
tan color vs gray. It's been written usually as tan/gray is just right as my
SU U20 used to run a tan. My current Mikuni Flatslides are running a medium
gray. Would gray be richer than say tan? My plug base ring is showing a
charcoal to black color and not rubbing off and no soot. They say it's
better to be slightly on the rich side to ensure engine safety so where do I
stand? Any opinions? Thanks Tom