Large WSM Runaway Temps

Hi there everyone!

I am VERY grateful that my wife gave me a large WSM for Christmas - along with some other cool BBQ stuff.

I fired the WSM up for the first time yesterday to season the grills and to see how it would behave, temperature wise.

I used the Minion method - but with no wood chunks. I was using briquettes and after building my mound of briquettes with the 'bowl' in the top, I lit ten briquettes in my charcoal chimney and once they were lit, I poured them into the bowl. I started with all three bottom vents open about 25% and the top vent open 100% I used no water in the water pan. since I was not actually risking any meat with this trial run (which turned out to be a good thing).

Things started out nice and seemed to be going well as the temperatures started to climb. The only time I had the lid off was right after I started the fire while I was placing the greased up grills in the pit. The entire rest of the time, it stayed closed.

Once the temperatures reached 275F as shown on the built in thermometer, I shut the three bottom air intakes down all the way - well, as all the way as they would go. Even closed all the way, there's still a tiny bit of an opening.

At 300F I tried closing down the top vent half way. The temperatures still kept rising. I closed the top vent all the way. The temperatures climbed to 375F with everything shut down. The cooker maintained 375F for several hours (five or so?) with all air intakes and the top vent shut completely down before they started slowly dropping. 8 hours later, it was finally down to 275F - it was running this hot even with all vents closed!

I am thinking of bending the 'stops' on the air intake wheels so that the air intakes close completely instead of leaving that tiny gap . . . but I don't want to start making mods without checking to see if anyone else had this kind of experience.

It also seems that there is a gap around the access door - once again, it's a very tiny gap, but it's definitely a gap. Like 1/16th of an inch of deflection.

Also, there was a steady wind at about 20mph sustained blowing on it and the ambient air temps were generally in the 20-30F range. I thought it might run a bit cool since it has such a large surface area to lose heat through but it seems that the wind along with the tiny gaps may have stoked the fire.

Anyway - I was wondering if anyone has had a similar experience with the large WSM and if there are any recommended modifications for this cooker.

Thanks in advance!

Thanks a bunch everybody! I sure appreciate the help.

Notley's absolutely right - the tiny gap that remains when the vents are closed down is because the tab that keeps the air intake covers from rotating all the way around are bumping into the fire grate. I will adjust those out a bit so that they don't bump into it and see if that reduces those tiny gaps.

Thanks again!