I have a kawasaki fb460v engine on an old john deere 36" walk behind mower I bought it non running. I put clean fuel in it and tried to start it nothing happened I checked spark it gets spark I pulled carb off and cleaned it and I pulled all of the jets out and cleaned them and put it back on tried to start it for round two it fired an ran for a few seconds when I went to throttle it up it died and would not start again there's a adjustment screw on the carb facing the engine I believe it's a air/fuel mixture screw I didn't adjust it or mess with it it's the only thing I can think of does any body know the adjustments for it and how to adjust it some people say the engine has to be running and air cleaner on to properly adjust it or is there something else keeping it from running.