I use an unmodified Smokey Joe gold and have a couple thoughts. Yes, the flaps are sufficient to completely block airflow. IF they fit flush and have the proper curve. They can easily get bent, but are just as easy to bend back into shape. My guess is that you're leaking air where the pot joins the bowl. A simple test is to light a good bed of coals, put the lid on the bowl, close all the vents and clip the bail in place. Your grill should be cool to the touch in about a half hour. If it's still hot, it's an issue with the flaps. If it's cool, it's an issue with the fitment of the pot. If it is an issue with the pot, make sure it hasn't gotten bent out of round. Again, it's easy to bend back if it's bent. I have noticed there is a pretty big variance in size in the Imusa pots. So it may just be that yours is on the small side and not seating in the bowl. A gasket of some sort will help this, or riveting the lid to the bottom. Just cut out the center of the lid and set the pot in it, then rivet it in place. I was able to do this with my first one as the pot fit perfectly in the lid, but my new one won't fit. Again, variances in size. Hope you get it worked out as these are great little cookers!