Pinyada,
When you installed the base gasket did you make sure that the holes in the bottom of the carb base lined up with the slots in the base gasket? It sounds like the holes in the base of the carb might be plugged by the gasket. Sounds like the power valve might of lost its vacuum signal because its vacuum port is plugged by the base gasket.
Try removing the carb and making sure that none of the ports in the base of the carb are blocked by the base gasket. The slots in the gasket should line up with the holes. Good luck and keep us posted.
