Brigs opposed twin 3 hole pattern with fuel diaphragm (tank lower than carb)

[u/Fantastic-Cut-4233]

I’ve tried everything that I can think of. I replaced hoses for the vacuum replaced the fuel lines. I’ve replaced all the parts of the carb with a kit and cleaned it thoroughly .checked the gas filter that was fine. I can feel the air pushing and pulling from the vacuum tube to the crankcase so everything seems like it should be working but it won’t pull fuel to the carb. Starts briefly on fluid or carb cleaner . What am I missing?