Mechanical Fuel Pump Stops Pumping Fuel

Hi all. I have a Corolla AE80 with 3ALU engine. It was running with a replaced electric fuel pump since the day I bought it. It s original mechanical pump was broken. Since I wanted it to run in the original way, I bought a new mechanical fuel pump, which is not OEM probably. I installed it correct and re adjusted the float bowl valve so that fuel level inside the bowl will remain within limits.*

At the beginning it did not work. Not a drop of fuel out. Later I used my old electric pump to prime the mechanical pump and then removed the electric pump. Then it was working fine. Fuel outlet gave a good stream of fuel. I ran the vehicle for few*kilo meters and then it stop. I happened to find that the pump is not pumping fuel any more. Once again I primed the pump and same thing happened. I primed the pump for like 5 times and I end up in same problem.*

Is this pump out of order? But it is new.:screwy:

I used a transparent tube between pump and filter. I happen to notice that air bubbles are drawn towards the pump. Could this be the problem? Should I make sure that no air is drawn in to*fuel lines? :eek7:

But even if I make sure that no air is drawn, what happens when fuel vaporized once kept sit for a while? Won't there be air trapped inside fuel lines? Shouldn't the pump be able to deal with it? :runaround: