not sure why its stalling but I had a similar problem with my CVH engine running a fast tickover, took me ages to work out what was causing it
It was traced to the automatic choke stepper rotor thats between where the throttle cable linkage at the carb & the carb body,
As I,m not using the auto choke its not connected but the stepper rotor was sitting at the higher revs position as if it was "thinking" it was a cold engine, I think there are 3 steps on the rotor so I just "adjusted" ( fixed in 1 position
) at the lower setting & hey bingo it solved the high tickover problem
Might be a similar problem on your engine
cheers
andy