I have a Smoke Hollow 38208G with a brass burner. I have good heat control for low to high heat. I'm just concerned about how much is too much yellow in the flame. On low I have good blue flame with a touch of yellow at the tip, when I turn it up to Med. or High I have about 1 inch of blue with 2 to 3 inches of yellow flame. Is this too much yellow flame ? and if it is can something be done to change it ?