I would suggest using a better carb. The Russian carbs were not all that great. But sometimes you got lucky and got a decent carb with the engine.
I just replaced a carb on a Russian/Soviet engine I was playing with earlier. In that case you could not lean out the idle mixture at all on the carb so the engine only had engine stop,  3/4 throttle  to WOT,  but no idle and no in between.

But now the carbs aren't all that cheap and can be quite expensive in some brands, so then one has to determine whether it is worth it or not. it helps to have accumulated extra things like carbs over the years, so you don't have to buy a new one you just rummage through your old parts boxes for something to use.