testing carb with impulse

[justcollecting]

I have a 410 that I am working on and it isn't sucking fuel. I just took it back apart to make sure the impulse port is clean.  My main question is I have a Walbro WJ and a WS. I have rebuilt both but it doesn't seem there is any pop off with the needle. Is that normal for a carb with the impulse line port? Is there a special way to test the carb with the two inlets? 

Thanks in advance.

[onlyhomelites]

The fuel circuit side should pressurize the same way as a standard carburetor, but I haven't seen a spec for the pop-off pressure. You'll want to pressurize through the black cap port.