I am trying to learn how to use my gas grill as an smoker. I bought the Brinkmann Smoker Box and have experimented a couple of times. Problem is that either the wood just dries out or it catches fire and burns up. My wood is apple and sits in water all the time. I use the far left burner which is probably not as hot as the far right burner. There are four burners on my grill. How can I get the wood to smoke? Thanks.