The same problem occurs on the bayou 220. I've had mine for 20 years, and one of the main problems is the mikuni vm24ss carburetor.
While the 24ss is a simple carburetor it also has a major fuel quality & contaminant problem.
I've cleaned and flushed the entire fuel system and all it takes is a tiny bit of rust or old gas to block the carb.
There is such a tiny confined space between the float tank and the main jet needle that just about anything can block the fuel from exiting the carb into the motor.
I did the same as you and it does indeed work. Methyl Hydrate also works on shelack build up, and of course the air compressor.
I found that the flaw was the bottom float chamber gasket. Once it becomes thin (compressed) over time .
I changed the gasket and it worked. I then put the old
gasket back on and put the new one over it to see if that improved the spacing and it did an excellent job. Even with the second gasket the floats did not need re-adjusting.
Lastly i added a generic in-line fuel filter between the tank valve and the carb fuel hose.
I hopes this helps.