when you say set, do you mean just the speed or have you adjusted the mixture, then speed then mixture, then speed etc etc, like you're supposed to?

recently with the onset of cold weather around here i had to adjust my idle mixture screw about 2 turns richer and then adjust the speed, as my ute was idling radically (if at all).

you can also buy a can of carby cleaner and spray that through each barrel.

Do your carbs mount with those vibration isolating things? The O ring seals?

If so, then go & buy a couple of new ones, then pop the carbs off one at a time. These O rings do have a finite life span & it sounds like yours might be sucking air. If your O rings are NOT in poor condition & sucking air, then keep the new ones for later as the old ones will eventually deteriorate.

As I said, it sounds like it's sucking air somewhere & these rings are a relatively common cause.

loose throttle linkage? Are these dellortos?

over the last few drives, i have noticed the idle weird on the ute, i have it set aboout 800. but when you pull up at the lights it sits on that then drops down 2 400rpm. and sort of goes up and down, like its going 2 stall.then every now and then it stays on 800, sort of all over the place. is this common, or is something up