I have been having problems with my Nitro evader st .18 engine as well.

il get it so it starts and idles fine, but when i take off, it will bog out before hitting top speed.

then il adjust it so it runs perfect, il drive around for about 20-30 seconds and the engine will stall..
then it wont start.
so il adjust it so it starts, and it will run and idle fine.... Back to the top^^

and just keep doin that loop.

any help on tuning it properly?