Triumph Repair: 1972 triumph spitfire, stromberg carburetor, brass screw

Question
Hi Howard, I have a 1972 triumph spitfire with the single stromberg carb. The car starts fine but after about 30 or 40 seconds, the car will idle somewhat high ie. 1500 to 1800 rpm's. The carb was rebuilt with a new kit. There is a needle valve screw on the side of the carb ( i think it is the idle trim screw) but doesn't seem to make any difference when adjusted. The vacuum tube is in place. Any suggestions,  Wayne

Answer
Hi Wayne,

The most common failure of the Stromberg carburetor is the auto choke system. (which can hold the throttle open)Look at the fast idle adjusting screw to see if it is holding the throttle open after warm up.

If you are talking about the large brass screw directly in the side of the carburetor, that was a trim screw used by the manufacture and should be closed all the way off. It is no longer used.

Howard