I have an MES 40 20070311 that I bought last year. I seem to be having trouble smoking meat to the correct internal temperature. It seems no matter what I do, I get a stall and can't finish the meat without seriously cranking up the temperature or finishing it in the oven. I have 2 internal probes (same readings), and I've verified that within a degree or two, the temperature of the unit is right on.
Last year, I tried to smoke to 6-8 pound butts for pulled pork. Both times I stalled for 6+ hours right about about 155 with smoker temp at 225. I got some advice on that, and I know that every piece of meat is different, and this could be normal, so that's what I figured, and I'd just plan for more time.
However, yesterday I tried to smoke some salmon. I did have every rack being used, but each rack wasn't "full." I put the biggest pieces on the bottom, and started the smoker at 145 for 4 hours, then turned it up to 180 to try to finish the pieces to an IT of 140*. After 4 more hours at 180* (IT stalled at 126), I turned it up to 210*. After 3 hours at 210* the IT still wasn't up to 140, but stalled right at 132. This piece of salmon was the biggest piece about 2.5" thick but only about an 8" long piece. I had to take all the other salmon out, except for the big pieces, move them to a seperate rack, and crank the temp up to 240* for a half an hour before they finished.
So, now I'm not thinking that my first two stalls weren't just meat related. During this salmon smoke, I used the AMNS and it worked fine. I had the water tray in there, but I didn't have any water in it, just foil. I had the vent fully opened, and I only opened the door about 4 times total, each right before bumping the temp up.