Sounds like your High Speed needle is closed. Have you closed it down and opened it 2.5 to 3 full turns open? Your Low Speed needle may need to be open 3 to 4 turns from fully seated, to start with. You also may need to turn the engine over at a quick pace to get a cold engine to fire. The...
Here's a helpful vid on breaking in a new engine. There's a part 1 and part 2.
(25) Part 1, Of How I Break In My NITROs with Pull/Roto Starts, LOSI 8IGHT-T&B RTR - YouTube