Here's a new one for me....:(

[Double Venom]

Tommy, I agree totally to all. I too read the info on the Pump and read it is adjustable.
With a regulator I ASUME the pump is pumping maximum pressure. 14 lbs. +? If there is a regulator buried on this thing somewhere I haven't found it! (But I will look again today!) The pumps 'intake' is located just inches from the tank and about parallel with the top of the tank. The output of the tank is what I originally custom made; a 1/2" pickup 14"s long, running length wise in the tank. It then feeds out at the lowest section of the tank then 'UP" about a foot. The weight of the fuel alone should force fuel into the pump!

All information I have ever read says the fuel going into the carb should be 5.5lbs minimum. Motor doesn't miss or act like it is starved even under maximum hang on load!

Also so, being carbed; Holley-this is not a closed or a return type fuel injected system needing a return line.
Read: Out of Gas, the floats are fully down, opening up the jets in the carb,allowing air from the system to escape under pressure. 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!

DV

I think more info to come on this situation!

[Tommy]

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.

[jagrolet]

ed
one thing that i have found years ago, is that most pumps,(electrical or mech) do not draw fuel very well from below their level.Basically,most electric pumps are "pushers" not "pullers".

In 1972 i had the same situation with a 66 bb vette,the hot ticket at the time was ac delco industrial strenth electric pumps. After a bunch of head scracthing and pump replacing,the pump was put as low as possible with the scrub line of the tank,and with no upward motion of the infeed line to the pump.
I sure wish i could remember that part number,it may have been in the motion hand book.

Also,check (if running carbs) manf"s recomended fuel pressure to needle seat. This is one of the major mistakes people make with holleys (it results in all kinds of mayhem). And what gives alot of holleys a bad rap.