If ethanol fuel has been stagnating in your fuel system for more than two or three months, an ultrasonic cleaning bath won't always clear that glue-like gunge from the jets and airways. This is particularly true if the carburetor are not stripped and are just dunked in a tank as an assembly.
You often need an old-fashioned approach, and that means going to someone with the knowledge and confidence to go inside the carburetor, stripping out every component and individually cleaning them as well as all the drillings in the carburetor bodies themselves. Sometimes they'll need to use chemicals that could cause damage if used incorrectly.
We know about a person who recently bought a motorcycle that had been stood for a time. He spent a small fortune on replacement ignition components because he'd had the carburetors cleaned in an ultrasonic bath, so he ruled them out as the cause of his continuing running problems. But with one run on the dyno mechanics were able to show him how the fuel/air mix was all over the place, particularly when put under load and different jets and airways were struggling to work.