Have no fear, the mess will lesseen as the run time on the motor increases, and will eventually disappear. If possible, you should enquire from the person you purchased the combo from what type of oil and what is the mix ratio of the fuel he gave you.

Nowadays there is a popular trend of thought that breaking in a motor on a petroleum based oil and then switching to a synthetic oil is a waste of time, though it is felt that the practice never hurt any.

Using regular 87 octane unleaded gas and a good quality 2 stroke oil specifically designed for air cooled motors and mixed as recommended by the manufacturer is usually the way to go.