There are a lot of factors that could cause it. Is the engine mixture set right? That would be my first guess is that it is way too lean, from the sounds of it. Did the engine get really hot? The next thing to check is the fuel getting to the carb. Were there a lot of bubbles in the line? How old is the fuel you are using? How much pitch do you have on the main blades at 3/4 stick and full stick? Is the glow plug bad? Is there something in the carb, has it been cleaned. Those are the things I would start with first. I would tie it down and get it running right before i tried to fly it. I used to do this for everything when I was starting, just to make sure it was set up and not vibrating and such. Start there and see what you find. Hope that helps some.