Your propane barbecue is supposed to produce uniform, blue flames. If it doesn’t, something’s up!
If you’re getting weak flames, yellow flames, or no flames
Assuming there are no leaks or any other obvious problems, one common cause is the barbecue’s regulator. It controls the flow of propane between the tank and burners, and has a safety switch that restricts the gas, which can be accidentally triggered. (This can happen if the last person who tried to start the barbecue didn’t do it properly. Thanks, that guy!)
Solution: reset by turning off all the burners, plus the tank, and disconnecting the regulator. Wait a few minutes, reconnect, and try again.
If you’re getting flashback fires
The culprit is often a clog in the venturi tubes—the tubes that feed gas and air to the burners—from dirt, dead insects, or spider webs. If the tubes are only partially blocked, you can get weak flames or no flames, as above. But if the tubes are fully blocked, the gas can’t get through to the burners and it comes back out, towards the barbecue’s control knobs. Terrifying fireball!
Solution: remove the malfunctioning burners and clean out the tubes with a pipe cleaner, or a specialized curved venturi brush (you can find these at hardware stores).
If you’re getting constant flare-ups
Some flare-ups—when you’re grilling fatty meat, or meat coated in oily marinades—are normal. But if they’re happening all the time, you probably need to clean your barbecue’s grill grates more frequently. (The food remnants won’t just burn away on their own.)
Solution: scrape the grates with a grill brush (there are non-bristle options out there) every time you use your barbecue. Also inspect your grease tray or pan, and scrape it out whenever it’s full.