Expert: John Langenfelder - 5/20/2008

Question
Hello John, I wonder if you can help? I have an elderly Char-Broil Gas BBQ which was running just fine, however it started to turn the food black with soot and I suspected that the LPG was not burning correctly, I have removed the burner assembly which is quite a simple affair and cleaned it through and wire brushed the Air Bleed slots, as well as checking that the Gas Jets were clean and the delivery hose clear, and a test cook of a couple of sausages went well with no apparent soot, however the burner flame is still burning with a distinct yellow tip. I can see that this is quite a crude gas appliance and as I cannot see anything actually wrong and as there are no adjustments Im wondering if its in fact common for cheap Gas BBQs to burn poorly? Am I expecting too much in looking for a nice blue flame? Look forward to hearing from you,
Steve.

Answer
Steve,

How dirty was the grill?  If it has been sitting all winter, this soot might be normal if you haven't cleaned it. I think it is obvious to say that cheaper grills may not be as efficient as more expensive grills but has it always been this way or did it just start?  How hot does the grill get when the burners are on full and the lid is closed?  If not more than 350 degrees, then you definitely have a burner problem.  However, it could be the regulator.  As you said it is an elderly grill and purchasing a new burner or regulator may not resolve the problem.
 
Three things to try:

First check the setting of the Venturi.  This is the area on the burner(s) which allows air to mix with the gas. It may be open slightly and it may have a screen to prevent insects from getting inside. Too much or too little means yellow flame and less heat. Play with it when the grill is own (please be careful not to burn yourself, it may get warm or be close to the burners) and adjust it to see if you get a bluer flame.

If this doesn't help, then:

Check the orifice at the end of the gas line which attaches to the burner for spider webs or an obstruction.  Clean it off with a q-tip just to be sure.  Same with the burner and also check the Venturi

For the third fix, try this:

Turn the burner control valves completely off. Turn off the gas at the tank fitting. (this may already be that way).  Remove the gas line with the regulator from the gas tank.  The regulator is the round thing which attaches to the tank.  Turn the burner control valves on to full and purge for at least a minute.  Turn off the control valves.  Reattach the regulator/gas line to the tank and s l o w l y turn on the gas. Now turn on one of the burner control valves (generally one is marked to turn on to start) and start the grill.  Now turn on remaining valves.  Close the lid and let it run for 10 -1 15 minutes and see what the high temperature is.  Is it higher then before?  

If the same, it could be the burner(s), the regulator or both.  At this point, you could try buying a new burner and see if that helps and or a new regulator to see if that helps.  Or you might want to contemplate a new grill if you don't want to do the trial and error method.