Re: Can spark plugs that look healthy be sick?

Simpson wrote:
> Mike Romain wrote:
>> Usually a sick one will show in it's colour, like you describe your's 
>> showing a lean mix with their white ceramics.
>>
>> With a modified carb and rough idle I also think lean miss.  How did 
>> you set up your idle mix screws?
> 
> Hi, Mike... I use the Lean Best Idle method described here:
> 
>
http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm
> 
> But even if I fatten up the idle mixture considerable, I still get a 
> rough idle. I have read that a rough idle is common to this particular 
> version of the Dodge/Chrysler 3.9L V6.
> 
> Steve W's first reply in this thread speaks to the nature of this engine

> that causes it to idle roughly:

Yup, sometimes there is just so much you can do to the old beasties...

The emissions sniffer gives me better readings by a 'whole bunch' with 
only 1/4 turn lean on both idle mix screws.  Once is was a fail/pass 
difference, I got the retest on the spot.  That gives the engine a 
little rumble at idle.

A little on the carbs can do a lot when you are right at the cusp of a 
perfect mix.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08.  Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com