Leave the starter battery on for a bit & let the engine warm up for about 20 seconds(remember everything is cold). Then ease the power up SLOWLY. This will give plug a chance to clean up(unfoul). If it won't continue the idle, then you probably aren't drawing fuel from the tank yet. Reprime and try again. If it will idle but quits when advanced slowly you may need to adjust the needle valve. Turn the the valve clockwise 1/4 turn. This will lean the engine slightly. See if this makes ANY improvement. Did you get the RTF with the Evolution engine, if not what kind is it? Getting old, memory shot. Slept since then and other excuses I can't remember either. Be very careful near moving propellers, best to adjust for now with motor not running. Have someone help hold plane if you can. When you get near the correct mixture you will be able to open the throttle quickly without it lagging much. It is a new motor, don't push it too hard yet.
Is it gas, oil or both coming from the muffler? Common for some unburned oil residue to come out.

Bruc