[TR] Weird spark plug behaviour

[Adrian Jones]

Hi Folks,

I've just taken the plugs out and noticed 3 and 4 had a white coloration.
This is strange because when I first got the car I rebuilt the carbs and have not touched them since.
This was 9 years ago (wow) and about 17k miles.  (about every 3 months I look at the plug color - always has been a nice tan-brown)
So I richened the rear carb (for plugs 3 and 4) by two flats on the jet.  Went for a 10 mile drive and plug 4 color had changed to yellow!
So I richened the rear carb (for plugs 3 and 4) by two more flats on the jet.  Went for a 10 mile drive and plug 4 color had changed to tan-yellow.
So I richened the rear carb (for plugs 3 and 4) by two more flats on the jet and leaned out front carb 1 flat (plugs 1 and 2 look a little rich)

Went for a 10 mile drive and here's what they look like now, left to right plugs 1, 2, 3, 4:

http://i12.photobucket.com/albums/a241/AdrianJones34/Plugs.jpg

So, the rear carb has been enrichened by a total of 6 flats and still no sign of sootiness.
Car runs great.

Any idea whats going on?  (If you have a suggestion would you mind emailing me.  I'm on Digest and was hoping to drive the car to my new job tomorrow.)

Cheers,  Adrian TS 58324