I have developed another (or complemetraty) way of cleaning carbs as mine was in the ultrasonic wash with no luck. I grabbed a fuel pump from some old car, attached a hose to it and shoot the carbs with pressurized technical petrol. Still no luck, but i could see exactly where im shooting and where it comes off the carbs, plugging various holes with my fingers. All holes free to flow (you can feel the pressure).