<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SMeadows:
Well I got a wild hair last night and decided to attempt my first overnighter. I decided to forego the injection and smoked with hickory. Cook went OK, except couldn't get temps below 280. I used minion method and put approximately 35 lit over top a full chamber of unlit (weather was calm and approx. 60 degrees). I opened all vents until smoker temp was 190, then closed all vent until all were about 1/4 way open. Temps seemed to stabilize around 235 (put butt on @ midnight, went to bed around 12:30). Maverick woke me up @ 1:55AM because temps reached 300. I closed all bottom vents and temps stabilized around 280 and wouldn't go lower.
Any thoughts on why I couldn't get lowered temps? Maybe too many lit coals to start? The butt is resting in the cooler right now (pulled @ IT of 195). I'll post some pics after its pulled. </div></BLOCKQUOTE>
I can't say if too many lit coals was the issue without knowing how long the cooker was monitored from the time of putting the dome on til putting the meat on. I usually let the cooker come up to temp and let the smoke clean up some, about an hour or so before putting the meat on. Then, I'll monitor a couple of hours or so to see what's gonna happen once the meat loses it's chill, maybe make a vent adjustment, top the pan off, and then tap the cooker legs with a rubber maul before hitting the sack. I use the Maverick as well, hung in the top vent. The temp range depends on when I want it all done by and what's cooking, but basically, I like to bbq pork butts somewhere in the 225-275* range.
What did you use in terms of a heat sink? I really liked how things went on my rib/chicken cook this week with a 12" clay pot base in a Brinkman charcoal pan, but I can GUARANTEE ya that if I were to only cook one pork butt overnight, there's gonna be water in my pan. Put a cold pork butt in a little wsm, and that's naturally gonna put a damper on things for a while....until the meat loses it's chill.
Regarding being able to shut the vents all the way and still MAINTAIN 280*, clearly you have some significant leaks. My cooker ran hotter when new, and did seal up and run cooler after several cooks, but check out the troubleshooting section of Chris' site regarding tweaking the door and checking for out-of-round.
Sorry about the trouble, but look at it this way: you just have an excuse to make more BBQ!