I fixed a brand-new, fresh out of the box GMS47 the other day by doing this:

1. shortened the spraybar by about 0.5mm.
2. drilled the brass insert to overcome the mis-alignment problem.
3. added teflon tape to the remote needle-valve so as to kill the air-leaks.

Now it runs just fine.

Before the mods it could not be richened enough to get it 4-stroking without also richening the idle mixture to a point where it simply would not transition. As a result, the engine would die shortly after take-off, every time.