Your situation may differ, but I ditched a commercial ultrasonic cleaner (800watt, 10 litre) due to it failing to adequately clean fine interior circuits on larger carbs. Sometimes it worked fairly well, others it merely superficially made it look clean. Again, I'm not saying yours was not properly cleaned, just that I found them ineffective far too often. I decided there is no substitute for getting hands on when ensuring fully clean carbs. Even then sometimes I have to repeat the process. It just happens.
And another used carb might prove a quick but still somewhat inconclusive solution. Might also introduce further complications. OB1 again offers good advice above and I'm inclined to agree.
Sorry to be so seemingly unhelpful, but Murphy lives in my shop most days and I've learned to be ultra fussy about procedure. Might not be carb at all, but repair by forum is tricky at best.