Keep at it don't get discouraged. Make sure your fuel tank is vented. Pull your plug, rotate the prop, check for spark.
Don't try to start it above idle speed. Use your choke until it wants to run then disconnect the choke. Put at a little pressure on your fuel system make sure the gas is flowing through the carburetor. The valve that the diaphragm opens was stuck on my carburetor and wouldn't allow any fuel to go through. Since you've had yours running I doubt if that's your problem. Make sure your high and low screws are open 1 3/4 turns to start with, you will probably have to turn them in some when you get your engine running. I believe the carburetor and ignition system are of good quality. We won't know about the engine itself for a while. I was using a 22-8 zinger prop today it is quite heavy. Tomorrow I'm putting a top-flight 20 - 8 prop on it much lighter. We'll see if that takes care of some of the vibration. I have gotten some answers from United hobbies. I think they are so busy because of their low prices that they just can't take care of everything. You also might try getting some help from your local flying club.

Good luck Bob G.