Dashpot System Check

Connect tachometer to engine. Warm engine to normal operating temperature (cooling fan on). Disconnect vacuum hose from throttle control valve.
Connect hand vacuum pump to throttle control valve and apply 8 in. Hg vacuum. On Civic models, disconnect vacuum hose No. 6 from throttle controller with engine idling. Engine speed should increase to 1400-2000 RPM.

Fig 1: Dashpot System (Civic)
On Civic models, loosen lock nut and turn adjusting nut. See Fig 2 .
If speed cannot be adjusted, or diaphragm will not hold vacuum, replace throttle controller and retest.

Fig 2: Adjusting Throttle Controller (Civic)