I've took it apart and clean for few times already. There's some problem with the head,probably. Start getting a slight birning taste and misfire out of the tank.
Not a big deal. I'll just retire the whole thing. There's no point to fight it.
Thanks for the help thou.,
Have you read any of the threads on the new post insulator being used by Kanger? The new insulator has been responsible for air flow blockage in a large number of reports.
It might be worth searching for and reading a few of the threads.