Symptoms were gas was giving a red orange flame and producing a lot of black soot indicating an incomplete burn of gas. Looking at burner you can see rust corrosion at various spots along gas tube and pipes on burner. Bought new front and back burners to fix it. Since it was thirty year old, I did not think they still made the replacement parts, but I was surprised they still do. Looked at a short video of how to do it before doing this project. Had the right size hex screwdriver handy, took out two hex screw that held old burners to plate, Removed old burner and replaced with new burner, screwed the two hex screws back on, and adjusted airflow with a flat head screwdriver and kept opening at same size as old burner opening. In total took less than 5 minutes. Gas flame is now blue with no soot problem on pans .