Throttle Controller Diaphragm

['89AccordLX(Rus)]

Hello,

I'm in the process of rebuilding/exploring a spare carburetor and am a bit dumbfounded by the throttle controller. What is it's function? I have also tried applying vacuum to the diaphragm and it doesn't hold. Is this normal or should I get a new throttle controller? Also, what are the sizes of the vacuum lines on the carb? I have found two different sizes so far, one of which seems to be 5/32" (4mm) while the other I suspect to be 5mm (? in) Thanks in advance for any help.

[A20A1]

Hello,

I'm in the process of rebuilding/exploring a spare carburetor and am a bit dumbfounded by the throttle controller. What is it's function? I have also tried applying vacuum to the diaphragm and it doesn't hold. Is this normal or should I get a new throttle controller? Also, what are the sizes of the vacuum lines on the carb? I have found two different sizes so far, one of which seems to be 5/32" (4mm) while the other I suspect to be 5mm (? in) Thanks in advance for any help.

5/32"

The throttle controller works when vacuum is low
This low vacuum could be due to too much throttle, a Strain on the motor because of accessories running causing low idle speed, or it is purposely bled when accessories are turned on
Bleeding or low vacuum causes the spring on the diaphragm to open the throttle which raises the idle
When you raise the idle you get a better vacuum signal as long as the throttle doesn't open too much
The increased vacuum signal pulls on the diaphragm and resisits the spring inside lowering the idle.
It's a vacuum balancing act...

the diaphragm should hold vacuum if vacuum is applied directly to the port.

['89AccordLX(Rus)]

Thanks A20A1, looks like I'll have to hit the junk yard for another diaphragm since mine won't hold vacuum. Thanks again for the help.