I bench tested the pump with the filter in place, slight trickle of gas coming through. I took the filter out of the hose and the pump just gushes. Seems this little fuel filter was causing the issue, strange because it was allowing strong flow when I first assembled everything. The petcock has a filter but I'd like something better in front of the pump. I'll see what Canadian tire has. I'm sure glad I don't need a replacement pump. And to the safety cops, yes this was stupid - potential sparks next to open fuel containers.