378:
While it's idling, pinch the fuel line. If it quits right away, its to lean. Open up the needle valve closest to the engine 1/4 of a turn. If it gradually speeds up quite a bit and quits,its to rich. turn the same needle valve in 1/4 turn. When it's set right it will rev up a bit before it qiuts. If it stalls when you rev it up, open the needle a bit till it doesn't stall. Used to run a small motor shop before I retired. Hope this helps.