Vacuum Gauge Test

1. Run the engine until normal operating temperature is reached.
2. Turn the engine off.
3. Connect Rotunda Vacuum/Pressure Tester 164-R0253 or equivalent to an intake manifold vacuum source.
4. Start the engine and operate it at the specified idle speed.
5. Read and record the value shown on the face of 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.

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