Kohler m16s carb issue

Wondering if anyone else is familiar with a Kohler m16s motor.

I have it on a leaf vac and it ran fine before but now will only run on choke and leave the plug black and sooty.
I even put a new carb on, new fuel lines, filter and plug. But am wondering if the mechanical fuel pump be weak as it has no suction against my finger with the filter unhooked and cranking it.

I did have it off before to do some work am thinking I may lost pressure or something