I've seen that gasket in a couple of YFs I've disassembled and I'm now wondering if that's what allowed the warpage? You're right...it isn't paper thin. Some of the screws you'll find seem like they were tightened by an air wrench. If an extra gasket was in there it might let the corners go down further as it is compressed causing the warpage in the center of each side. Thinking about it, that gasket would cause another problem, too. It will raise the bonnet by the thickness of it (1/32 or 1/16" maybe?). That will raise the top collar of the bonnet by the same amount (which governs where the little clip on the diaphragm rod stops) and if the metering rod isn't adjusted downward by the same amount at that time, then it will fail to hit the bottom of the jet well at the proper time. That will throw the rod out of kilter by that amount, so the step from low speed to mid range to the richest setting will take place sooner...meaning you'll be running richer as the rod is pushed upward. No, it doesn't appear in any of the Carter data I've seen. I wonder if that was somebody's answer to this problem. Sort of like the people who try to compensate for the Rochester B and BC warping by using 2 gaskets stacked on top of each other.
