Yes I have flown them without the cowls and still the same issue. I also have the ignition batteries fully charged, 2000 mah and 4.8 NMH brand new. I find it very wierd that 2 engines both started doing the same thing. I did recently mix a new can of gas and even though that has a filter on it also I am wondering if that could be the problem. Again both engines start and run fine on the ground, at all differnt throttle settings and takeoff's are not a problem and up until a week ago they have been running great. It's only when I get about 3 min into the flight that they start bogging down and then quit. I have readjusted the needles back to original settings and still no luck. I'm going to throw out the gas and make a new batch. I have gotten real good at dead sticking[&:] but I'm getting tired of walking to get my plane[:@]. Thanks again and keep the ideas coming.