The key here is that it is a new engine. So you are starting the break-in process. Every engine manual I have read recommends starting the engine with the high speed needle quite rich, advancing the throttle to full, and then leaning the high end for a few seconds. After running near peak RPMs for 10 seconds or so, richen the HS needle again to let the engine cool down a bit. Say a minute or so. Then you lean it again for a slightly longer time, then back rich again. Continue running it near peak (just slightly rich) for longer and longer periods, until you finish the tank. At this time most OS engines are about ready to fly, as long as they will idle for 10 or 15 seconds without dying.

By all means follow the break-in instructions in the manual.