1)The smell of gas in conjunction with the burner flames appearing yellow and lazy.
2)Barbecue does not reach temperature.
3)Barbecue heats unevenly.
4)One or more of the burners do not ignite.
DANGER
Failure to correct the above mentioned symptoms may result in a fire, which can cause serious bodily injury or death, and cause damage to property.
Replacing Main Burners
1)Your Weber Gas Barbecue must be OFF and cool.
2)Turn gas OFF at source.
3)To remove control panel: take off the burner control knobs. Remove the screws holding the control panel in place. Lift off the control panel.
4)Unlatch the Spider Stopper™ Guards and remove them.
5)Remove the manifold bracket and unscrew the two wing nuts(1) that hold the manifold to the cooking box. Pull the manifold and valve assembly out of the burners and carefully set it down.
(1)
6)Slide the burner assembly out from under the guide screw and washer(1) in the corners of the cooking box.
(1)
7) Lift and twist the burner assembly slightly, to separate
the crossover tube(1) from the burners. Remove the burners from the cooking box.
(1)
8)To reinstall the burners, reverse 3) through 7).
CAUTION: The burner openings(1) must be positioned properly over the valve orifices(2). Check proper assembly before fastening manifold in place.
(2)
(1) 
9)Reinstall the Spider Stopper Guards. Slightly rotate the Spider Stopper Guards so that the seams are in line with the Venturi fins(1). There should be no gaps in the seams or in the fit around the burners(2) and valves(3).
(1)
(3)
(2)
CAUTION: If the Spider Stopper Guards do not fit tightly, contact the Customer Service Representative in your region using the contact information sheet provided with your manual.
WARNING: After reinstalling the gas lines, they should be leak checked with a soap and water solution before using the barbecue. (See Step: “Check for gas leaks.”)
2