Loss of Torque on low end any thoughts? 1999 BOW RIDER 5.0L

[190BOWRIDER]

I am wondering if anyone can give me some insight or advice on why I am having some problems with loss of low end power. Recently have noticed I am having a hard time pulling up a skier from a stop but once I get past 2000 RPM the top end kicks in and there isn't an issue. Not launching anymore like it use too. I have the carb. model and not MPI. Ordinary operation is good, all pressures are within specs as far as the gauges are reading. Recently changed out the fuel filter/ water separator. And had some problems getting it to idle on its own, but after a half hour jockeying the throttle and letting the engine run it leveled out and operated normally. Thought maybe there may have been some air in the fuel line that worked its way out. New to this, obviously.