Adjust the idling up to around 800, most cars will now idle under that. There should be a screw to do it with near the cable on the carburettor.
Check if the IDling wire is connected
dirty or plugged idle jet and/or passage- clean or replace jet. clean carb.
float bowl overfilling causing flooding at idle- check needle and seat , check float.
vacuum leak - carb , intake manifold ,check gasket's , vacuum hoses
leaking or burnt valve
good luck car
75 Spitfire won't hold idle. It starts and revs normal. I can hold the RPM low (in the hundreds) with the gas pedal, but if I take my foot away it dies. I worked fine last summer and I haven't messed with it.
