I know you have probably tried this but keep on repeatedly cleaning the idle jet out, by taking it out pulling it apart and blowing through it with carb cleaner, once the carbs been apart i have always had to clean mine a million times (maybe a slight exaggeration
) before it would run right. Seems to carry on blocking up for a while.
Also i once cleaned it out so many times and it made no difference at all, not sure why but i checked the idle jet with a magnifying glass and there was a tiny bit of the threaded part in between the silicone hoses trapped in the end that the carb cleaner wasn't shifting.
Again just another few simple things to try.
Darn carbs!