I assume that you are talking about the carbs.
Possibly you have a diaphragm not seated/working correctly?
A quick check of the diaphragms:
1) Remove air filters.
2) Lift up the brass barrel and then block the upper slot on the carb (the slot that kind of looks like a upside down U). If the diaphragm is good. The barrel will stay up until you remove your finger blocking the upper slot on the carb.
Trent aka Okiesnake