what is the purpose of the microswitch near the throttle linkage?

mine is has recently broken - the arm that presses on the switch broke, but the switch itself is still ok, although it can no longer be activated by the throttle linkage. As a result, my idling speed is very high on startup if the engine is cold. This was pointed out to me by my mechanic, and on startup, I sometimes need to manually activate the switch just to get the idling back to somewhere near normal.

I also noticed that my engine's torque is not so good in the midrange, and when I give it the boot, I sense irregularities in the torque curve, as the engine winds itself up under load. My guess is that this could also be related to the microswitch, because I noticed this only recently.

mine is an M103 2.6 engine.