in-line elec fuel pump not pushing through mechanical pump

[69a]

2 PSI is more than enough to prime the system (motor off). This will pressurize the the glass bowl, the fuel pump and fill the carb. Switch the electric pump off and start the engine, you will now have the mechanical pump pressure (yours is set to 3PSI) between the mechanical pump and the needle valve on the carb. and negative pressure on the glass bowl. If it is sucking air at the bowl gasket it is difficult to detect.This is why it is important to have a good seal on the glass bowl.
If you have both pumps running you could have 5 PSI at the carb. I'm not 100% sure about that.