Choke - or another carburettor control (8)
I believe the answer is:
throttle
This clue might be a double definition.
'choke' is the first definition.
(synonyms)
'another carburettor control' is the second definition.
'throttle' can be an answer for 'control' (throttle is a kind of control). I'm unsure of the 'another carburettor' bit.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for throttle that I've seen before include "Valve to regulate the supply of fuel to the engine" , "Strangle; fuel controller" , "Accelerator - choke" , "Fuel-regulating valve in an engine" , "one of the controls in a car" .)