[Healeys] Setting SU HD Carburettors

[Derek Job]

Gary that is a very interesting comment you make about the throttle
adjusting screws not being confused with the fast idle screws.

I seem to have a pair of HD8s on my car which do have throttle adjusting
screws as well as fast idle screws. The slow running valves were screwed
down and the adjustment has been made on the throttle screws. I still don't
fully understand this though. For instance, what is the purpose of the
throttle screws if the carbs operate fine without them. What extra benefit
do they offer. Any ideas?

Derek