Small adjustment or fix to a toilet float to fix constant draining?

Question

Two days ago and previously the sink worked properly. Yesterday I noticed it was continuing to drain after a flush [through the drain pipe in purple]. The reason is that the actuator [in red] does not get lifted/float properly. A "fix" [but needed after every flush] is to simply lift the actuator [pictured in purple ] a little and let go.

This problem does not seem to be addressable via that screw on the actuator. Instead maybe some part of the broader mechanism is a little 'tight', causing the actuator/float to stick? What can be done to fix this: is there any cleaning or adjustment? If not what should I replace?

Update. I have found a more specific "fix" to this. The cylindrical black portion of the float gets "stuck". If I bump it to unstick it the actuator arm lifts up as well and then the draining stops. I did add a small shim to ensure the black piece were not contacting the back of the sink bowl (it was..). but surprisingly that did not make a difference

Answer 1

screw in the thing that stops water flow so it turns off before it reaches the overflow.

Answer 2

This "answer" is actually a further explanation of the one from @TigerGuy that I just accepted. Yes the answer was to turn the screw. I had not done it earlier because the screw was jumping around on the top where the head is and at the bottom where it meets the thread. [Note: the thread is not visible since I was unable to get a good exposure photo. It is inside the red rectangle].

So I was initially unable to understand whether the screw were simply broken. The answer from @TigerGuy made me more insistent to get the screw to work.