Here is what CEN had to say about needle settings earlier in this thread:

Quote:

"Here are settings that we end up using after the engines completely broken-in with 20% nitro fuel. Your settings will be different but this should be close.

Main Needle, 3 ½ turns out
Bottom Needle, 2 ½ turns in from flush.
Idle Screw, Adjust to keep engine idling smoothly."

Try running at those settings, also try a new plug, check for air leaks in the fuel line and make sure carb, backplate and head screws are tight.

If all else fails, call CEN and get a new one - sounds like you're still covered by the warranty.