Turk1

Evgeny as I mentioned on other threads repeatedly there is only one flaw in NGH carb. LSN profile cant restrict enough at low throttling zone and it gets overrich due to pump pressure (because there is so high suction on fuel line from crankcase).
If you play only with  LSN profile to gain better restriction down from half open barrel then you will have a great running engine.
Another  solution is,to remove completely regulation system from pump and leave it only as a pump unit.Put a "return  to tank line" using a T conn. at carb inlet nipple.Then having a great running engine.
My observation shows NGH 9 engine has excess suction at low throttle zone resulting regulator to open for excess fuel to carb and LSN is the reason of all.If you can make a perfect LSN profile to restrict suction enough then regulator will not get fake signals to stay open for excess fuel which is the reason of erratic running.