I recently bought this mower at a yard sale and it starts fine but it idles erratically. I bought two little springs to go on the carb from a B&S website and I know where the big one goes but I am not sure how to, or even IF to, hook up the little one. Does anyone have a picture or diagram of this model that might show me where this thing goes? This spring may not even be my problem, but in any case I would like to get it hooked up correctly and then go from there. Also, how does this "throttle-free design" work anyway?