I got a Ofna Ravager (force .28 engine) for Christmas today. This is my first nitro engine. Whn I went out to try to break it in it seems to make a weird clanging noise. It will start up for a few seconds but then clang and die. Does anyone have an idea of what I'm doing wrong?

Another thing I forgot, could anyone tell me how to tell which needle is the high speed and low speed needle?
Thank you