You must break in your engine with the throttle wide open and vary the speed with the needle valve.

If it were my engine, I would not allow it to four-cycle at all. A rich two cycle can be maintained without overheating the engine. This type of engine needs to run warm right away to allow the upper cylinder to expand to normal size and not wear the piston prematurely.

If you run it at a cold fourcycle for the first minute, it may loosen the fit of the piston and liner, this is exactly what you don't want to happen if you intend to have a powerful, long lasting, engine after break-in.
You would want to run a ringed or iron piston engine very rich right from the start, but not this one.