Check your fuel line in the tank by dumping the fuel and see if the filter has comes off /out due to bad line. If the filter does not fall out, use wire or needle nose pliers to fish it out to examine the line. Next, remove your air filter and examine the fuel line at the carb and primer bulb. If lines are needed, Sears and Home Depot had kits for less than 4.00 (with directions on the kits, I Think, but easy). The exact one you need, "Probably" the larger in the kits will cost you 2.00 at a Small Engine Shop. jow

Sounds like your low speed circuit is restricted . Tag wire and carb cleaner along with compressed air to follow with internal passage cleaning . Also you can check the filter as loger has suggested , although since it runs well at high rpm fuel restriction on the main circuit does not apear to be the problem . Never hurts to check anyways along with the inlet prefilter (screen) within the carburator on some models .