Last night, I noticed that a burner on my cooktop was giving off a yellowish flame, indicating insufficient air in the mixture. I turned on the other three burners and got the same yellow-ish flame.

Because it affects all four burners, I’m guessing it is caused by an obstruction to the air intake that feeds all of the burners, and the fix may be as simple as removing a clump of dog hair somewhere. I can’t figure out where that would be, though. My trusty Reader’s Digest fix-it-yourself manual says I should be looking for an air shutter somewhere. I have successfully lifted up the cooktop to expose the guts, but I can’t find anything that looks like the picture in the book.

Suggestions?

Thanks for the reply.

Natural gas. If each burner has its own air shutter, it seems unlikely that all four shutters went funny. Is there a way to test the regulator, other than by replacing the old one and seeing what happens?

Eureka! (Probably.) Just got a new ultrasonic humidifier the same day I noticed that the flame color changed. I've switched off the humidifier and will check the stove later this afternoon. You probably just saved me a $ervice call!