I have very old car its Daihatsu Charade 86 Model, I am facing this issue since few months. Sometimes when i park the car for 2 or more days then try to start it, it doesnt start. I noticed that fuel filter was empty, then i pour some petrol from the top of the carburetor, car starts and fuel filter is getting petrol from fuel tank. And when i tried to suck the petrol through pipe from the filter it fills full but just when i stopped sucking the pipe, petrol is started to draining from filter to fuel tank.
But when car starts by pouring the petrol on carburetor it doesnt create problem until i stop it for 2 or more days.