you can't set the idle untill the throttle arm on the carb is set all the way back to idle position!!!!!!it will die when you give it brakes.
This is what you need to do. (engine not running, air filter off)
#1. take out the screw that is holding the servo horns on the throttle
#2 remove servo horns off the throttle servo
#3 turn on radio and reciever and set throttle trim to the middle
#4 now you can move throttle arm on the carb by hand. Note which way
full throttle and idle is.
#5 by hand move throttle arm on carb to idle position and put the servo
horn back on(make sure the arm on the carb can't go back anymore)
#6 while looking into carb (air filter off) adjust the idle so the hole in carb
Doing this insures you that when you first turn on your radio the servo puts the engine in idle position.
This is what most likely why the engine quits when you apply the brakes