Spring-loaded screws by idle diaphragm

I have a carbureted 89 accord LX. Can you guys please explain what the two spring-loaded screws near the idle diaphragm are for?

The reason I'm asking is that I tried setting the idle by turning the throttle stop screw. I was able to set the idle when the car's in P or N. But when I turned on the headlights and shit with the car in D, it then idles too low and shakes. And when I turn up the throttle stop screw it's fine but then it idles too high in P or N.

I've read some stuff about these screws in previous threads but don't quite understand. So are these the screws I need to set?

Any advice is much appreciated. It's been very frustrating!!!

Byron

make sure the car is fully warm
turn out the idle diaphragm and a/c idle boost screws so they don't effect idle...
set the idle with the throttle stop screw without the headlights on. it should be at 900 -1,000 in neutral

go in the car a shift into gear and the idle should drop to 800 - 900

up the idle a little with the idle diaphragm so thats it's between 1,000 - 1,100 in neutral... now turn on the headlights and vent fans and see how far the idle drops... adjust the idle speed using the idle diaphragm back to 1,000 - 1,100 but when you turn off the lights and fans the idle should not go above 1,100

now turn on your a/c and set the idle with the a/c idle boost screw.

go back into the car and shift into gear... idle should go down for a second and then steady between 900-1,000 rpm.

I could be wrong and the a/c idle boost screw is the one the should be set instead of the idle diaphragm when the headlights and fans are on. in either case just make sure you set the idle below 1,100 in neutral and usually above 900 in gear.

I have no A/C but I get the idea now.

Thanks again.