1. The carb should not fill with the motor turned off regardless of the tank pressure. This is caused from several things. First, at three turns out you are richer than needed ven for break-in. Two, possibly a bad seating of the gasket in the regulator. Three, the regulator might need to be turned in a little bit. Do not be afraid of turning the regulator. Just remember what turns you make.

2. The motor is probably flooding at three turns out. Two turns is fine for break-in.

3. Use an aluminum spinner with all YS motors. Most plastic spinners will give way with a rather violent and potentially dangerous explosion.