Dunno about a Cooper but on an MGB the carbs are interdependant and after
adjusting one you have to recheck the other. If you adjust that you then
have to recheck the first and so on.
You need an air flow meter, or at least a listening tube and a good ear.
Check/adjust the jet centering as previously advised.
Adjust the jet screw until the top of each jet is flush with the bridge,
then move them down two full turns of the screw or nut.
Slacken all the throttle and choke interconnecting clamps. Adjust the idle
screw on each carb so there is an equal amount of air flow as indicated on
the air flow meter or as judged by ear using the listening tube.
Tighten the throttle clamps, recheck the air flow at idle, then check it off
idle at about 1000rpm. If the air flow was balanced before but isn't now
you will need to make small adjustments to the interconnection clamps until
it is balanced both at idle and off idle.
Adjust the mixture with jet screw and listening pin on each carb in turn
until the required effect is obtained on both. On earlier engines this is
max idle speed, which should coincide with a momentary increase in idle
speed as the lifting pin is lifted 1/16". If the idle speed stays up the
mixture is too rich, if it doesn't rise at all or dies it is too weak. On
later engines mixture should be weakened until the idle just starts to fall
from its highest, then turned back to regain its highest.
Adjust the throttle cable so that there is about 12 thou play in the cable,
the carbs must be sitting on the idle screws at idle and not hanging off the
cable.
Adjust the choke interconnections so both jets start to move at the same
instant, and not before the control knob has moved 1/4".
Adjust the fast idle screws to get the appropriate idle (1500rpm on an MGB)
with the choke pulled out 1/4" making sure that each has the same air flow
using the meter or listening tube as before.
Thereafter discipline is required! As long as you only ever adjust both
carbs in the same direction by the same amount they will remain balanced for
many thousands of miles. If you ever tweak just one carb, or alter them by
different amounts, then you will have to go back to the beginning to get
them balanced again.
> agoblez wrote:
> >
> > I've had my Mini Cooper for 3 yrs now, I've bought every book that I
> > could find on S-U carbs and still can't get mine tuned to what I
> > think is correct and proper.
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