Sound like you arent preheating the engine and the idle is too low.
read this....understand it

http://www.rctech.net/forum/offroad-...eak-bible.html

then go watch this on youtube

https://www.youtube.com/watch?v=oViIFCYKA1s
https://www.youtube.com/watch?v=zy70c4D6mZM

also, if it's true that you have only basic knowledge about tuning/ breakin i think it will be wise to pay the extra to get it run in because an O.S speed is not exactly something you want to use as a test subject for learning the ins and outs of breaking in a racing engine for the first time....might turn out to be an expensive lesson....just saying