What they said. I've found lint, hair, ghost turds, dirt and all sorts of stocking stuffers inside various carbs in the past when my engines were giving me fits. This is in spite of running a filter on my fuel jug and an inline filter before the carb. Somehow, that stuff still sneaks its way in there over time. Once, I had a brand new ST that I could absolutely not get adjusted right and ran unpredictable. Later that day after getting home, I yanked the carb apart and found aluminum shavings from the machining process inside the barrel. And this was one of the older Italian made versions, so I don't necessarily buy into that crap that the Chinese versions are any worse than the European ones.