Ok I've been chasing a problem on my new to me 99 gp800 it set for 5 years

I rebuilt the carbs and set everything to stock.
replaced a Pv that was missing
ski runs great on the top

it has a weird bog on the bottom end and you kind of have to feather the throttle to get it on top end...HOWEVER if you pump the primer (choke removed primer installed) 2 times it instantly comes out of its bog and goes to wot running great...

this is tells me I'm not getting enough fuel or it's delayed getting it..

Where do I go from here ? I've eliminated the filter, and fuel selector as a culprit as well..

Thanks In advance