ok i have an 86 sammi with the stock 1.3. I am wondering what would cause the 2nd barrel of the carb the one closeset to the block to not open more than 3mm. while the motor is running ... i mean i can open it more while running but at throttle even full throttle it only opens about 3mm. i know there is an electrical vac. switch/little green box that the vaccume linkage connects to for that barrel what is suppose to engage that switch?

the second barrel opens on vacum and you will not get enough to open it if it is not under a load setting still wont do it