---

Agree with Tmann.

Does the fuel line to the motor have a primer bulb? When the engine stalls, is the bulb flat (collapsed?)

Check the vent first. Look at the vent opening from outside.
Next, access the vent fitting and remove the hose clamps. Blow into the tank.

If cause not found, I would replace vent hose, fuel fill to tank as well as fuel line to motor to the alcohol resistant type.