bought this to fix fuel drain back problem

After sitting for several days I have to crank my engine for about 5 seconds then pump it 3 times and it starts, my problem is the fuel evaporating out of the carb after a hot shut off, and ethanol fuel. I don't think a carb will empty through the needle and seat. Your problem having to crank that much might be a tank not vented correctly, pickup sock clogged, or a faulty pump valve, but if the valve is working its probably a bandaid for one of the problems I listed. Also if your going to keep that in the line make sure you have a screen filter at the carb inlet, if the check valve fails and a needle sticks open there may be a fire risk.