MY first truck,bought off e-bay,ran sweet,NO issues,thru 4 tanks...,now it seems I have to progressivly richen both needles a tick every other tank to maintain the "sweet spot",I'm now up to 3 1/2 turns on both needles,and just made my first adj. on the idle screw,when doing adj. I insure tank is full to prevent the "half tank lean" scenario from throwin me off,also,befor the engine is primed for initial start-up, the OWB on the pull start slips,but after priming, no problemo.....could an air leak from this area cause these issues........or is it just the atmospheric blues.........[:-]