What makes the engine stall when only using the arm out. It makes slight black smoke TVC valve is clean and its pressure decrease when load increase Does the main control valve makes it behave like this if it has internal leakage
If it is only happening when moving the arm out , that is ruling out engine fuel power problem. Maybe someone else who has worked lots on them will chime in. Maybe post your serial number as it can make a difference. Simon C
I think a leaking regulator will do this CO, NC or TVC, mainly when pressure increases almost above 200 bar and when return pressure increases also