Surprisingly, chimney cap height is crucial to your grill’s proper performance. If you choke it down too far, it creates pressure inside the grill which can result in temperature fluctuations.
The chimney on your Daniel Boone or Jim Bowie series grill should always be open at least as much as shown in the picture on the left. In warm weather, you should open it even further.
On the Davy Crockett model, swing it all the way open, all the time.