Walbro WT891 carb on a Craftsman chainsaw. Carb is brand new, all fuel lines and fule filter replaced. I prime the carb with the little plunger, chainsaw starts up and runs out of fuel within 30 seconds. The line coming out of the primer bulb is dry but gas remains in the bulb itself. Seems that the carb cannot pull the fuel up past the bulb. Fuel line comes from fuel filter in tank to primer bulb and then to lower inlet tube (near diaphragm) on carb bottom. Upper tube on top of carb goes back into tank. thanks, for any suggestions.

Who connected these hoses? the normal routing for a machine with a primer is like this, the fuel hose from the tank with the filter on the end goes to the carb fuel inlet nozzel ( not to the primer ) nearest to the pump cover ( cover on carb held with one screw ) the pipe from the metering side of the carb connects to the shorter nozzel on the primer bulb ( suction side ), the longer nozzel on the primer ( pressure side ) connects to the pipe going back to the tank, just remember the primer pulls fuel from the carb,into the bulb, and pushes it back into the tank, it is not actually a primer it is a purge. because it is connected this way it is impossible to flood the engine no matter how many times the bulb is pressed.
Let me know if it starts and runs.