Yes, that single carb and that horrendous manifold must have run like crap without the heat.
I don't know if it will help much, but I found when I left my grungy pistons soaking in a mix of ATF and gunwash / cellulose thinners (with lots of toluene, acetone, xylene, etc in it) for a few weeks, they came out entirely grunge free and the erstwhile stuck rings were free as a bird and shiny.
I'm not sure how quickly the miracle occurred, because I wasn't checking.
So, entirely by accident I found a de-carb method that really works.
Now, if I could find a de-carb method for my gut, that would be great.
Another method would be to use the old 2-stroke silencer de-coke trick of setting it alight and feeding it oxygen. You'd need the oxy/acet setup first though, and not many places have it now.