Uneven flame on one burner only: what it means and what fixes it

An even blue ring is what a healthy burner looks like. When one burner goes lopsided while the others are fine, the cause is local to that burner, and it is usually mechanical rather than a gas problem.

The cap is not seated

The most common cause and the easiest fix. Lift the burner cap, wipe the rim and the base, set it down flat and turn it slightly until it drops into its locating notch. A cap resting a millimetre high on one side starves that side.

Ports are blocked

Boil-overs leave residue in the small holes around the burner. Where they are blocked, no flame. A soft brush and warm water on a cold burner clears most of it. Do not use a pin or wire — enlarging a port changes the flame permanently.

The jet is partly blocked

Under the burner is a small brass nozzle. If residue has reached it, the whole burner runs weak or lopsided even with a clean cap. This one is a technician job — the jet is part of the gas path and needs the right tool, not a needle.

The mixing tube has debris

Between the jet and the burner, air mixes with gas. A spider web or crumbs in that tube changes the mix on one side. Also a service item.

If the uneven flame is also yellow or lifting off the burner, do not keep using that burner. Those together point to a gas-air problem that needs a proper look.

Order of operations

Cap first. Ports second. If neither fixes it, book a visit — the remaining causes are all behind the burner.