I'm NOT an emissions expert (well, people standing behind my
Mustang may disagree :-) ) but I'll add about a penny's worth anyway
Jim writes:
> Well I failed my first time through the AZ emissions
> test, but not by much... Hyrocarbons were low and Co2
> was good at high speed, but the Co2 failed at idle...
I do not believe that this is a 'lean the car out' issue. Leaning
the mixture affects hydrocarbons more than CO (I'm guessing you
meant carbon monoxide, not carbon dioxide).
By the way, it is possible to INCREASE your unburned hydrocarbon
count by LEANING the mixture! My 1200 used to do that - it's called
a 'lean burn' condition - not enough fuel for a complete burn, leaving
behind unburned gas that goes out the tailpipe. That's why the 'lean
burn' engines of a couple decades back had emissions problems
(we'll avoid discussing stratification - an old idea that pops up now
and again)
> I had the timing at 0, dwell right on, idle at 1500,
> and SU carbs leaned to a 1/4 turn from the top stop...
That's a high idle. Good for testing, bad for driving.
> Just want to confirm that the SUs lean out as the
> mixture ring at the bottom of the carb compreses the
> car adjustment spring and moves the nozzle upward...
Yup. But if you're 1/4 turn (hmmm, one and a half 'flats') from
full-on lean, your carbs are a bit out of whack. Typical setting is
a full 2-3 turns. Are the needles set right (Shoulder flush with
the piston body)? Do the jets look good (nice and round, not
oval from wear)?
> Can anyone tell me if there are leaner needles I can
> purchase for leaner idle?
High altitude needles. Keith Williams knows all about R-16 needles :-)
If someone donates him a U-20 maybe he'll figure them out, too :-) :-)
> Passing an emissions test for a 32 year old car is a
> pain...
Not in California any more :-) Sorry, I couldn't help it...
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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