Very new to the hobbie but i just came in the house from setting up the throttle on a new O.S. .46LA and it idles nice first try this is what i did.
With the throtle trim all the way up & the throtle stick all the way down

Losen the screw on the on the control arm on the servo horn and hand adjust the rod until you have enough of an opening in the carb about 1/16 open (you might have to play with this your opening might differ)

once thats set re tighten the screw with thredlock

GL