The burners on an LP (liquid propane) gas range should produce blue flames with yellowish tips during normal operation. If there is more yellow than blue in the burner flame, or if the burner makes hissing and sputtering noises, the air-to-gas mixture may need adjustment. The range burners are each equipped with an air shutter that can be adjusted to improve the fuel efficiency of the appliance. Adjusting the air shutter with a screwdriver takes only a few minutes.
Turn off all burners and wait for the range to cool.
Lift off the grate from each burner and set aside.
Pull up on the range cooktop and raise toward the back of the appliance. Many ranges have a steel support rod to hold the cooktop in the upright position. Lift the rod and insert the tip in the hole on the underside of the cooktop.
Turn the setscrew in the air shutter next to the burner counterclockwise to loosen the shutter. The air shutter is built into a metal tub that feeds LP gas to the burner.
Push in and turn the control knob to light the burner you are adjusting. If the flames are excessively yellow, slide the shutter wider until only the tip of the flame is yellow and tighten the setscrew. Narrow the shutter to stop hissing sounds and sputtering flames, then tighten the setscrew.
Lower the cooktop and replace the burner grates on the range.