As I don't have a 20cc size, I would set as in the DLE manual, it is at best a starting point. all of my engines starting at 26cc up to 62's all seam to set at the following Low needle 1 1/2 open, high needle 11/3 for starters, and remember the low needle controls the mid range.

That said good luck and keep your fingers out of the prop as gas engines wack a lot harder then a glow of the same size.

Cheers Bob T
AMA13377