When you first start the engine, you will find it really difficult to pull the starter, loosen the glowplug for the first idle tank (not alot only quarter a turn) until it's started, I've used a pull start before now and it's been impossible to pull (actually broke one on the first engine i did). I was a bit weary about it until at least two model shops told me to do the same as you can jam the pull start, but just be careful and don't leave it like that as you can blow the glowplug out.
Forget the failsafe for now, focus on running your engine in.