If you are sure every internal passage is clean then the carby must be damaged Norm.
Fuel Passage Corrosion or Micro Cracks
Older carb bodies sometimes get internal corrosion, especially if ethanol fuel sat in them.
This can restrict internal drillings or create an internal leak path between air and fuel galleries.
Ultrasonic cleaning canβt fix that β only replacement will.
the internal passages in the old carb arenβt truly open, even after ultrasonic cleaning.
