a couple things, first drop the regulator pressure, then close the air shutters a bit until the flame tips turn yellow. With the classic Brutus design there is no where for the flame to go unless about 4" of the bottom skirt is cut off, or 1/2"-3/4" spacers are paced on the frame to let flame out. If you put more flame under the keg you do not always get more heating, just useless flames up the sides. The optimum is where the flame tips just touch the keg bottom, if the light blue area just off the burner touches, then the flame produces lots of CO and soot.
If the flame lifts off the burner the pressure is too high and or the air shutter is opened too much, and you are probably having difficulty lighting them and they are noisy, not quiet like they should be when adjusted correctly.