Ok, here is a check list for your most common gas grill lighting problems:
1) Check your tank. Is it empty or nearly empty? The tare weight (T.W.) of your cylinder is stamped on the collar. This is the weight of your empty cylinder, usually around 18 lbs. Weigh it on your bathroom scale
. Propane weighs 4.25 lbs/gal. If it weighs around 20 lbs or less - Refill it. If not, go to #2.
2) Make sure you didn't turn the gas tank valve on too fast. Some gas hoses have a built-in excess flow valve that stops the flow of gas to a trickle if opened too fast. Close the tank valve and let sit for a few minutes. Or just disconnect it and reconnect it. Turn the tank valve very slowly and then try lighting it again. If it doesn't help, go to #3.
3) Is the igniter sparking? Some are battery
powered-check the battery or replace it. If you have a standard push button piezzo igniter or a rotary style
igniter, check for spark. Can you hear or see the spark? It's hard to see the spark in bright daylight. It's easier to view the spark at dusk or dawn. It should spark an "arc" at the burner. If not, adjust it if necessary. The igniter wire may have a short, causing the spark to arc somewhere else along the wire and not at the burner. Replace igniter wire. It's also possible the igniter tip where it sparks has a cracked or broken porcelain portion of the igniter, causing the spark to not arc at the tip where it's supposed to. Replace the igniter piece. If not, go to #4.
4) You may have a rusted, clogged or damaged burner or venturi tube. With a flashlight, check for spider webs, wasp nests or dirt (mud) dauber nests in the opening of the venturi tube where it connects at each gas valve orifice. Clean it out manually or blow it out with air compressor. Make sure the air adjustment opening (on the end of the burner's venturi tube) has not been changed. If it's closed too much, it will be difficult to light and cause lazy yellow flames. If it's not clogged, the burner may just be old and rusted and the burner holes are not allowing very much gas through anymore. It's also possible the burner has rusted so bad, the burner holes have been enlarged, it is falling apart or has cracks along the burner seams. If so, replace the burner(s) immediately. It is unsafe to use. Your local propane co can usually order the parts you need and some will even do the work, if you are uncomfortable doing it yourself. Bring with you the Make, Model and Serial number of the grill, so they can order the correct parts for your specific grill. Also specify whether it's natural gas
5) If none of these resolve the issues you are having, it is also possible you have a faulty or defective regulator, which may mean replacement. If the pressure still seems too low and none of the above has helped, and you have a silver/gray regulator; many have an adjustment screw on the top center of the diaphragm. Remove the outer cap and turn the inside screw clockwise in 1/4 turns to increase the pressure until the desired flame size is accomplished. Flames should be as blue as possible, but will burn orange if there is food or drippings on it. Yellow flames are not good, and will soot up everything and not cook as hot as blue flames do. Yellow flames could mean you do not have the right air shutter adjustment, clogged burners, or possibly defective burners, as mentioned above in #4.
6) Also make sure you have the hose connection tightened snugly to the propane tank valve to ensure the inner valve seat is fully depressed allowing gas to exit fully without any restriction. The black plastic female fitting should be hand tightened only. Older versions that use a left-hand male brass POL valve, requires a 7/8 open end wrench or adjustable wrench to tighten.
Hope this helps! Good luck in your trouble shooting! Douglas