When I work on a troublesome carb I take it to the small engine shop and get them to put it in the ultrasonic cleaner. It has always worked even when the carb is caked in green sludge. I used to rebuild a lot of old tractors and chainsaws that you just can't find parts for. They charged me $10.00 to put it in the machine for an hour or so. it hits all the passages with thousands of tiny bubbles that go at the speed of sound or You can buy a small ultrasonic cleaner for $50.00. I have only scrapped 2 carbs out of hundreds over the years and that was because moisture caused some parts to rust and pitted the insides so bad it could not be saved.