Briggs and Stratton Carb Throttle Shaft Replacement?

I replaced the throttle shaft on my 11 hp B&S engine, model/type/sn 253707-015501-84073011 (from an '84 JD 111 lawn tractor)and am having problems adjusting the carb. I'm concerned that I may have installed the shaft 180 degrees from what it should be. I installed the throttle butterfly by sliding it thru the in-board side of the carb into the shaft slot and inserting the single screw and tightening it, again from the inboard side of the carb. I did not remove the plug at the back of the carb body to install the throttle butterfly. Engine seems to be running very lean, idle adjustment screw does not have any effect, only way to get it to idle slowly is to open the adjusting valve at the bottom of the bowl, making it very rich, which causes it to run poorly at higher RPM. Leaning that valve out causes the engine to race. There is a fixed lever on the inboard side of the shaft where the throttle cable and governor spring attach. My question is this: should that lever be pointing up or down? I can't find a good pic of both sides of the carb. I hope this is clear to you. Thanks.