Techumse carbs have always given me fits. That's why I'm glad they went out of business. Wish I could advise on a good carb cleaner. I don't know of any.
I have a Tech carb that will work at full speed, but the idle circuit is choked up. I took it apart and used compressed air, but no luck.
It's one of those EPA carbs with no adjustments. Hate them.
Plan to replace engine with a briggs tomorrow. Told my friends that if I ever buy another tech, they can kick me.