1996 loss of power going uphill

[itmup4]

I have a 1996 EZGO gas 4 cycle. It cannot hardly climb a hill. Had been running great, then this just started. I've cleaned the carb and jets twice. Put on new fuel filter and air cleaner. Checked all carb/fuel pump hoses. Checked and set valves (seemed to do a little better). Originally when problem started the plugs were gray and clean. Now after messing with the pilot screw (closed cw and backed off 1 1/2 turns ccw) plugs are dirty and black. Also have checked throttle adjustment and tweeked governor setting.
Problem seems worse the more the cart is warmed up. Runs pretty well on flat ground. Took off seat and ran cart uphill and see drive belt/clutch go from narrow (belt on top) to wider (belt drops) with gas pedal floored as cart slows going up the hill. I've since backed the pilot screw out 3 turns. Pilot jet is seated cw. What are the proper settings for these and any tips greatly appreciated.