> What year is the car BTW? It sounds like the you have adjusted the air
> bypass valve. The strange looking unit on the side of the carb with a
> triangular footprint is an air bypass valve. Its purpose (emissions and
> drivability related) is to maintain a minimum pressure in the intake
> manifold; if the pressure drops below a certain value, it opens and lets
> air bypass the throttle plate.
>
> If you haven't already taken the air bypass apart or adjusted it, leave it
> alone! It is factory preset and you aren't supposed to mess with it. Your
> problem is likely something else.
The Spitfires an 80 Federal model. EPA stuff is currently pulled, as the car
is first going
to get either historic or street rod tags, which exempts me here in Maryland.
I've already taking the air bypass apart (too late!) As well the idle fuel
mixing screw
(both coarse and fine). Thanks for the re-explanation of the air bypass valve.
Seems to me
that it also controls the air to the vacuum retard on the distributor. I'm
really regretting
not having drawn pictures of everything inside it a few months ago when I had
it all apart.
At this rate I may end up taking it apart again just to refamiliarize myself
with its
passages and such. If I do it though I am going to draw pictures this time!
> I think the choke control modifies the pressure ratio across the piston
> which enriches the mixture. Others may correct me on this...
Hmm, that makes some sense. No one else has written me (yet) about this
though. Gads, I'm
begining to suspect others don't mess with those carbs at all! And I'm starting
to see why.
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