okay i just got my new xxxnt and i am in the break in process im in about the 5th tank of gas i all of a sudden after i adjusted the low speed needle it wont start any more can u tell me what is the problem.

I would try to return the engine to its factory setting and start over. Check your glow plug and make sure it burns nice and bright. Prime the engine and see what happens.

what is factory settings for the xxxnt
thanxs guys

does anyone know commmon guys i need to know this

If you have a XXX-NT sport RTR with the Dynamite Mach .15 engine, then they suggest 2 1/2 turns out (counter-clockwise) on the high speed needle and 4 turns out on the low speed needle as a starting point. If you check out horizonhobby.com you can download the .pdf file for the Mach .15 engine. (dyn0880-manual.pdf) Click on mach .15 details, support tab on bottom of page. If you have a different engine, then horizon may still be the place to look. Also, get an infra-red temp gun to aid in tuning. It's $25 - $40 well spent. Hope this helps. Good luck and have fun!!!!!