Evap canister and tank vent help

[Jeffb]

Hey All, having a problem and cannot find any help. My 220 is starving for fuel. It runs fine on an external tank to the fuel separator nipple.

The shop looked at the pickup tube, feed lines and anti-syphon (I’m going to replace them all) but nothing jumped out. When checking the vacuum relief/vent, they weren’t able to get air into the tank from the vent. The hoses go through the carbon canister but it’s unknown if that is serviceable or if the hoses are setup correctly. Even with this setup, you should be able to push air into the tank from the vent, no? It appears as if the tank was worked on before I owned it, but can’t find anymore info on how this system operates or how to route the hoses. I never checked if it was vacuum locked before we tore it down but it seems like this could be the culprit. Anyone else experience anything like this?