What engines are you using? When you 'checked everything' did you check for garbage in the needle valve of the problem engine? As it takes only a small amount of crud to block things up a small particle may be floating around causing some grief. Do you use fuel filters? I use Sullivan 'Crap Traps' just before the needles on my B-29. If I have to adjust them more than a couple of clicks each way the first think I look for is crud in the needle valves. - John