I just got a used 2000 LT F 250. The previous owner said it started running bad about a year ago. Gas was pouring thru carb. Took the carb off, cleaned and rebuilt with new needle and seat (float was o.k.) Here is the kicker...there are 3 hoses on left side carb. One is fuel, one goes to fuel pump. The third hose runs to the 3 way fuel valve. When I put this hose back on, the carb won't idle and it floods out and dies quickly. If I pull the line off, it runs like a champ and idles. Any one knows what might be wrong with the carb?