Quote:
Originally Posted by Double Venom
In other words when the pump pumps fuel it will run along the line from the tank, to the filter then "through" the filter to the Carb. filling up the float cambers, eventually raising the floats high enough to shut of the flow, at which time the automatic by-pass in the pump takes over..... In other words NO air lock.! Hmmm????? Still thinking about this one!  |
I was thinking about that too and here's my theory. When the system is filled with fuel, the fuel filter acts as a restriction in the line. But as fuel is not compressible, it does not significantly affect the pressure in the fuel line. Air is compressible, so I suspect the fuel filter acted sort of like a resistor in an electrical circuit. I believe it provided just enough back pressure to open the 4.5 PSI bypass valve in the fuel pump, effectively stopping the pump from moving more air. Meanwhile, air on the other side of the fuel filter easily escaped through the carburetor, showing a pressure of 0 PSI. Given enough time, I suspect the fuel pump would have eventually pushed enough air through the filter to start pumping fuel from the tank. But it may have damaged the pump impeller by then.