I got the Cabelas masterbuilt 7-in-1 smoker for my birthday and have used it twice, both times I've had trouble maintaining the temperature. The first time I got it up to 225 but after a few hours it wouldn't get over 200 no matter how much coal I added. Second time I loaded up the bowl with coal and it wouldn't get above 175, then gradually dropped and held at 125. I'm using B&B oak lump and used the propane to light the coals. I also used a full water pan and the exhaust vent was fully open. I may try the minion method next, maybe I'm overloading the coal. I could also switch to sand in the water pan, but it seems like another issue. Any advice?