Help with Cox free flight helicopter

Hi Cox fans
I have a problem with my free flight helicopter..I run the engine in my hands as it rotates in my hand and all the fuel burns up.
How ever, when i start the engine ,run until rich and back up on the needle , and release it in the air it leaves about half the tank..
I never, had this type of problem...i replaced the reed value , back plate, and still the same old situation,,
is there something wrong with sure start Camancha, ..other the Cobra often burns all the fuel.

Thanks
Body123