The maroon/brown cam is a big cam.
http://documents.holley.com/pumpcamgraph.pdf I think there's something wrong on the accelerator pump circuit. Shooting from the hip, it's going to be one of these:
1) The linkage is screwed up and the cam lever is not getting pushed down right to actuate the pump;
I think this all will be easier to diagnose with the carb off the car. Agree?
2) The little orange umbrella seal is leaking, so you're not getting a good squirt in the right direction, or the diaphragm is worn out, or the spring is broken or missing (elves do that);
With the carb off the car, i might as well replace the diaphragm. How do you tell if the orange umbrella is sealing the vent? is it supposed to be flush with it?
3) There's a clog in the passageways from the pump to the nozzle;
That's in the metering block, right? Soak in carb cleaner or ??
4) The nozzle area is mucked up preventing a good squirt. You know there are two gaskets and that little plumb bob thingy that go under the nozzle. If you remove the nozzle and take it away to clean it, elves always sneak in your garage and hit the throttle, making the little plumb bob fly out and disappear. Are you absolutely positive it's still in there?