I been working on my 71 six preparing for its annual emmissions test. The
car runs beautifully, but I am unable to get CO down to the needed level,
ie, I can't get it lean enough. HC hasn't been a problem. The spec I need
to pass is 5.0% CO at idle, I can't get it below 8.0%. I'm using a Gunson
GasTester for measurement. I've leaned out the carb needle adjusters as far
as I think I go without unscrewing them from their sleeves (4 turns out from
tight). I also have the idle trim screws fully backed out.
The carbs were professionally rebuilt and rebushed several years ago, the
distributor has been rebuilt, and it's had a recent valve job. Dwell and
timing is set to factory specs. Any advice or ideas?
Thanks
Darrell
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