I too have the 140 but I run only one side currently,....The one closest to the door is running at about 75% and keeping the bottom living area of the 4400 sqft home at a nice 73 degrees..with the basement at about 80...
I unplugged the combustion fan motor and feed motor and placed insulation in the opening to keep hot air from escaping back out.
If the hopper is low or the fire is getting close to the rear of the feed tray you will get a smell also...I had to take my pipes all apart and vacuum them out from all the fly ash that had settled in it...
Previous owner must have never cleaned it out since the 8" piping was about 75% blocked.
I have been running only the rear burner and leaving a big coal pyle over the front burner in the hopper. I figured the rear burner wouldn't pit the glass as much as the front. I have the combustion blower and the feeder unplugged on the front burner.
Wow! Leadslingingdaddy, 8 inch pipe, clogged! I hope you have some good CO detectors.