Next questions - fuel Filter not filling

[WarpathEngineering]

So in order to get the truck safe to drive, I replaced the fuel pump. The old one worked well enough but due to it's age it was leaking around the diaphragm crimp. While trying to diagnose the faltering/flooding issue with the choke, I noticed that at high idle (1500 rpm) there was very little fuel in the clear fuel filter between the pump and carb. I sat there for quite a while waiting for the choke to open watching the fuel level in this little filter. It pump seemed to cycle in strength but struggled to fill the bottom of the filter up to the filter material and you could actually see the filter material whiten as the carb demand would pulse and it started to suck more fuel. The dual canister system on the truck has been disconnected from the engine but is still attached to the fuel tanks. I first wondered if the new fuel cap I just bought wasn't vented so I removed it while the truck was running but that didn't seem to make a difference. Is this normal or any ideas?????