Vacuum Gauge Test

1. Run the engine until normal operating temperature is reached.
2. Turn the engine off.
3. Connect Rotunda Vacuum/Pressure Tester 16-4R0253 or equivalent to the intake manifold where vacuum can be registered.
4. Start the engine and operate it at specified idle speed.
5. Read and record the value indicated by the gauge. The vacuum gauge should read between 17.7 and 22 inches depending upon the engine condition and the altitude at which the test is being performed. Subtract one inch from the specified reading for every 1,000 feet of elevation above sea level.

NOTE: The reading should be steady. It may be necessary to adjust the gauge damper control (if equipped) if the needle is fluttering rapidly. Adjust the damper until the needle moves easily without excessive flutter.