The needle settings as it comes out of the box is most often too rich for the engine to run right. Too rich is not a good thing as it doesn't allow the engine to heat up which is necessary for it to break in. Lean the low speed needle 1/8th turn and try running it again. If it's still not idling well and quitting when you hit the throttle, try leaning the low speed another 1/8 turn. After a total of a 1/4 turn leaner, use smaller increments until it will idle for about 10 seconds and still allow you to punch it and have it stay running. The top end can stay a bit rich as the idle needle controls fuel flow for about 75% of the throttle. As long as you don't run it too lean, babying it just prolongs the actual break-in of the engine as the higher rpm is what seats the bearings and conrod bushings. The piston-liner break-in on their own provided the engine is operated warm enough.