A carburettor choke works to adjust the amount of air that can flow into the carburettor. The less air, the more fuel will be delivered. In colder weather, adjust a Weber carburettor choke to restrict the air flow. This will make starting the vehicle easier. In warmer seasons, the air flow should be increased to lessen the amount of fuel delivered as this will prevent the carburettor from becoming flooded. Weber carburettors are easy to adjust as the choke is controlled by a choke ring on top, there is no need to remove the cover to access the actual choke butterfly.
Allow the choke assembly to cool completely if the engine has recently been running.
Loosen the three screws surrounding the choke ring with a hex head screwdriver. The choke ring is the raised round cap on top of the carburettor.
Hold the throttle open by pulling back on the throttle arm on the side of the carburettor.
Turn the choke ring 1/8-inch counter clockwise to increase the choke for colder weather and clockwise to decrease the choke for warmer weather. Release the throttle arm.
Tighten the screws with a hex wrench until they are hand tight.
Make adjusting the choke a regular part of the car's maintenance as the nuts can loosen with the vibration of driving.
Do not over-tighten the adjustment nuts or the choke plate could become warped.