S2a, 2.25 petrol, Zenith carb, 70k miles.
Running well, but running rich. Started after 5 secs with or without choke, small amount of black smoke while running, doing about 15mpg. All the indications are that it's running rich. Adjusted volume control screw as per manual to no effect, so I decided the carb needed an overhaul. Got an overhaul kit and did the work over the weekend.
Now it starts first turn and idles sweetly - even first thing with no choke. Misfires a bit when it's revved, loads of black smoke. Obviously running very rich. Adjusting the volume control screw makes no difference whatsoever to the idle speed, from fully closed to right out (at which point it stalls, not surprisingly. VCS is extremely stiff and almost impossible to turn (as was the old one). Substituting the old one makes no difference.
All I did to the carb was to replace the jets and economy device diaphragm and set the float level to the correct setting (33mm from the gasket face - it was 28mm which is 5mm out - but this would weaken the mixture, wouldn't it?). Obviously I've done summat wrong, but what?
Anyone any ideas? Or should I junk it and get a Weber?
TIA
Rich
Series 2a The rest