you need to start with adjusting the low end, ,ake sure the throttle is fully closed and stick a t pin in the air bleed hloe in the front of the card then turn the low speed adjustment in till it touches the t pin, start the engine set the idle a little high and pinch the fuel line it should pick up speed when you do. then open the throttle wide open and set the high speed needle by listening to the engine i do this by getting a good high speed sound the pinch the line it slhould pick up if it dosent its too lean turn it out about an 1/8 turn and repeat till it picks up hope this helps, if your not comfortable with this get an experienced pilot to set it up for ya dont butn your engine up the os la is an great engine and should last ya a while if you dont burn it up runnign it lean rickey