We haven't had a Solex question for a while.

First. The 'valve' you are referring to is the choke plate. When the engine is cold, you pump the gas once and they close. You start the car and they open as the the engine warms up. The opening is controlled by the expansion of a bi-metallic spring that is heated electrically. The "springing back" doesn't really matter. What is important is that they are closed when the engine is cold, and open when it is warm/hot.

Second. You can't just adjust the idle speed. There is a process to do this that keeps the carbs synchronized, which is very important. Do a search on this forum and you will find lots of info on this. Your low idle may be caused by unsync'd carbs, plugged idle circuits, vacuum leaks, or a bad idle mix.

Lots and lots of posts on these carbs.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe