I am having some trouble with my XXX NT engine - I ran it fine one day and then the next when I went to start it, every time I pulled the start cord, it wouldn't catch, it would just pull out smooth and go back in - I don't know if that makes sense - when you usually pull the cord, it sort of clicks every inch, well now it doesn't, sometimes it will click like the first inch, bit then after that it won't. If I pull it really slow, sometimes it will catch like it used too, but not always? Any ideas, I know this probably doesn't make any sense, but any advice would be appreciated.

The one-way bearing is probably gooed up with oil. Take the pull start housing off, being careful not to let the spool out, and remove the bearing and give it a shot with motor spray and reinstall it.

Get a fresh gallon of 20% nitro car fuel 12-14% oil (20/20 is fine), replace your glow plug with an OS 3 or OS 5 and try again. I also suspect your low end is a little lean.