Hello, I noticed you might have gotten your fuel lines mixed up. Im not sure if it would make any difference in the operation of the chainsaw.
But during the disassembly stage, you have the thick fuel return line going from the purge bulb outlet port to the big hole towards the front of the fuel tank. Yet during the reassembly stage, you used this same hole for your fuel supply line instead.
The correct routing of the fuel lines is actually the way it was before you disassembled it.
1: Thin line from right carburetor nipple gets routed through the small hole towards the rear of the fuel tank and is hooked up to the fuel filter inside.
2: Thick line goes from left carburetor nipple to the short nipple on the purge bulb.
3: And finally, another thick line goes from the long nipple of the purge bulb to the big hole towards the front of the fuel tank.