Start the engine and set it to idle speed.
Disconnect the vacuum hose from the second air valve and plug the end of the hose (A).
Connect the positive lead of the voltmeter to the negative terminal of the feedback solenoid valve.
Connect the negative lead of the voltmeter to ground. The feedback solenoid valve must be connected.
[The text of the article was taken from the website mitsubishiman.ru]
Let the engine run for 10 seconds at 2000-3000 rpm.
Immediately after reducing the engine speed to normal idle speed, check the behavior of the voltmeter. If the voltmeter needle fluctuates, and the center of the fluctuation is between 2 and 12 volts, the system is working correctly.
If necessary, adjust the idle speed with the adjusting screw.
If the voltmeter needle does not fluctuate or the fluctuation center is not within 2-12 volts, then check the operation of all mechanical elements of the carburetor and the holes of all jets. Repeat the check.
If the system does not work after repairing the carburetor components, replace the carburetor throttle assembly and retest. If the system still does not work, replace the carburetor.
Connect the vacuum hose to the second air control valve.