RE: Carburetor... how do glow engine carbs work?
For Colin Stevens, Colin I dismanteled the MVVS carb to make sure of the direction for leaning and richening the midrange. Rotating the adjustment CCW==richer midrange, CW==leaner midrange. The carbs in picture #5 all have a common trait, small adjustment equals big change, minute adjustments are the rule of the day.
Pic. #1 full lean
Pic. #2 full rich
Pic. #3 where this one runs best
Pic. #4 full rich.