I wouldn't use wd-40, that probably makes it worse. This sounds incredibly simple, but tap the vent tab closed with your spatula or tongs. Ash, grease, etc builds up but that's kind of how things work. Make sure the vent turns while cooking and it will have no problem moving at the end of the game.
Also, smokey joe, mountain, 22, 26, daisy wheel, etc., they all work the same.
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