It should. It should idle under full braking. the idle screwis under the air filter facing the front of the car it should hold the idle under the spring tension while braking. If it happens to start stalling under braking it could also be a broken clutch spring. but you will have trouble starting and the car will want to take off once you do get it started.OH when I got my Volcano the brake adjustment was way off. tighten the thumbscrew on the brake linkage with the servo in the idle position so the piece of tubing is just contacting the brake arm. Turn the controls on and do it on a flat surface. pushing the truck by hand on the ground I adjusted the brake so it had no drag in idle postion but would lock the wheels when braking. this keeps the backward pressure on the spring to a minimum. Hope this helps.