My 1984 XJ6 S3 last California smog check showed CO at “0”. To get to 2.5 % CO from 0, does anyone remember if the adjusting screw direction is CC ?;
and how much can be expected from 1 full turn? I won't see an Exhaust Gas analyzer for another 2 years.

See comments from Roger Bywater of AJ6 Engineering,

“Idle mixture on European cars is specified as giving 1-2 % CO, but these elderly engines seem rather happier at 2-3 %.”

Rgds David

 

Well I have just had a new California Smog check and can answer my own question about XJ6 mixture adjustments at idle.
I adjusted the mixture slightly richer two years ago.

This year took two tries to pass, as "Smog Tech" thought my fuel cap seals looked cracked !!!! On first run I was at .02 CO% at idle.
I turned mixture adjustment on Airflow meter 1/2 turn CW to decrease airflow, thereby increasing fuel.
On second Smog Test the idle reading was .07 CO%.
Per read out, the max allowed at idle in California is 1.0 CO %, while the Average of all California cars is .1 CO%
(I have added 1/2 turn CW since last test (Estimate is now .12 CO% at idle)
The hot restart issue is better now, as I feel it was too lean to catch quickly before.
(At 2500 RPM my reading on second test was .31 CO%, Max allowed in California is 1.2 CO% and average of all cars in California is .20 CO%)
Rgds
David