If fuel flows when the float drops (I'm assuming it hangs when installed) and stops when you push it up against the seat, then it's working properly. Small engines are no different than large engines, there's just less 'stuff'...
It really doesn't take much crud or sludge to stop the flow.
I used to keep a 10mm wrench in my car when I first got it running to clean the idle jets every 15 miles or so....
