i recall a technique, as far as i can remember, from jmac.


you turn off your engine, and then spray a generous amount of carb cleaner to the mouth of the carb, and be particular not to miss the jets visible from the outside. after that, wait for a couple of minutes, and then switch the plug lead of 2 and 3. this way, you induce backfire. turn on the engine and let then nurse it, so the backfire happens, and the engine not stalling. after 2 or 3 minutes doing this, switch off, switch back the lead of 2 and 3. and lastly, drain the fuel from the carb bowl. this is to ensure the dirt entering the bowl doesn't get sucked into the circuits again.

this technique work wonders a couple of times already.