Hello all,
I've installed a punto 75 camshaft on my 45 999 uno.
I had to disable the mechanical fuel pump and installing an electric one.

I have an issue of where to connect the return hose to.
My single carb has only inlet hose.
When I connect the return hose to a T along with the inlet hose, the engine doesn't work good, maybe it sucks air from that hose.

When I disable it like in this picture, it works ok.
Do I need the return hose connected to somewhere or I can leave it blocked?