Just saw your post, did you get your fuel problem solved? I have a 96 400 Sport (2wd) that had the same thing going on, it ha set for a couple of years, carb cleaned, new needle and seat, new jets, later a new float, same problem. It turned out that the ethanol dissolved the insides of the vinyl fuel lines and it was sending little pieces by the filter into the carb. Replaced lines, problem solved