A healthy gas flame is mostly blue with small yellow tips. Lazy orange/yellow along the whole tube is incomplete combustion: blocked ports, a closed air shutter, or a nest in the venturi. Dust in the air (pollen, new mulch) can tint tips briefly — that clears. A tube that stays yellow after a preheat is a part or a cleaning job.
This is not the same as all burners weak after a tank swap (excess flow: small blue flames). Port-by-port cleaning: clean burner ports. Nests: spider webs in the venturi.
Procedure
- Lid open. Preheat 10 minutes. Photograph the flame: one tube vs all tubes.
- All tubes yellow and tiny after you spun the tank: regulator reset first.
- One tube yellow, others blue: that tube’s ports or venturi. Not the tank.
- Cold. Tank off. Remove the grate and tent over the ugly tube.
- Shine a light along the port row. Black pinholes: ream with a tool smaller than the hole. Do not drill ports larger.
- Look into the venturi inlet. Web or mud dauber: spider procedure.
- If the tube has an air shutter, note LP vs NG. A shutter left fully closed after a rebuild runs yellow. Open to the previous mark; NG usually more open than LP.
- Relight lid open. Still yellow with daylight holes in the tube: replace the tube. Still yellow with a rusted tent above it: replace the tent first — grease is raining into the ports.
FAQ
Is a yellow flame dangerous?
A little yellow at the tips is common. A roaring orange tube, soot on the lid, or flame at the air shutter (flashback) is incomplete burning or a tube off the orifice. Shut the valve and fix it before the next cook.
Does yellow mean I need a new regulator?
Not by itself. Regulators that are tripped look like low blue fire on every burner. Yellow on one burner is almost never the regulator.
Related: finder.