I saw your posting and have found some information that may help you with the adjustment of the "KOALA" carb.
The "KOALA" carb is a replacement for TILLOTSON carb types "R" & "S".The car applications are as follows:
Durant Four,Models M2,M4(1928),40(1929)-R-6A
Durant Six, Models 55(1928),60(1929)-R-4A
Whippet Four,Model 96(1928)-S-4C
Turn main or high speed adjusting needle valve or clockwise until it is seated,then turn the needle vlave down,or anti-clockwise1 1/2 - 2 turns.Turn idling screwin or clockwiseuntil it is seated,then turn screw outor anti-clockwise1/2 -1 turn.These are approximate settings that will allow engine to be started and warmed up.Engine must be warmed up before final adjustments are made.
High Speed adjustment:
With engine warm and running,open hand throttle until engine speed is equivalent to 25-30 mph,and retard manual spark control.Turn main or high speed adjusting needle valve up or clockwise until engine begins to slow down due to lack of fuel.Then turn needle valve down or anti-clockwise until engine picks up speed and runs smoothly.This adjustment should be made slowly so that the needle valve is not turned beyond the point where maximum speed and smooth running are secured in order to assure maximum economy.Adjustment can be quickly checked by quickly opening and closing throttle and noting engine performance.If engine hesitates or misses,the setting is too lean,and the needle valve may be opened slightly.
Close throttle,leave spark control retarded,adjustthrottle lever stop screw so that engine idles slightly faster than normal idle speed.Turn idling adjustment screwout or anti-clockwiseuntil engine begins to hesitate or miss(mixture too lean),then turn screw in or clockwise until engine fires smoothly.Adjusting screw controls air ans should be turned out for leaner mixture,and in for richer mixture.Adjust throttle lever stop screw for correct idling speed.
Fuel level in float bowl should be 13/16" below the top edge of the bowl with the needle valve seated when the engine is not running.Float level can be changed to correct fuel level
by shifting the spool on the valve stem.
Hope this helps you out.