Set the needles to the manual-recommended opening and break it in in the air. It may take a while. Usually, when it stops spitting black spots, it's broken in. My G-23, G-28, and G-62 all did the same thing and took between 3-4 gallons to completely break in. It won't sag and die or flame out at idle like an unbroken-in glow engine will.

Dr.1