I know it should be somewhere on the bottom part. The problem is that carb is so tiny, I have no idea how are you supposed to drain that thing, unless you are a tiny spider that can crawl under the carb and use nano-screwdriver technology, considering that there is 1 cm space between carb and engine port. In fact, I have no idea how you can drain that unless you remove the whole carb (which defeats the purpose, I guess).