The best way would be to remove it and clean it with a soft wire brush and carb clean. But you can do it with some carb clean and a soft wire brush clean around the flap where if it seat's around the opening and the back side of the flap. Just make sure you don't spray a lot of the carb spray in there start it in between while cleaning and then shut it off and clean some more.
Please consider a to help us answer more questions.
Thursday, December 2nd, 2010 AT 6:23 PM