Test

Bring the engine to normal operating temperature. Connect Rotunda Vacuum/Pressure Tester 164-R0253 or equivalent to the intake manifold. Run the engine at the specified idle speed.

The vacuum gauge should read between -51 and -74 kPa (15 and 22 in-Hg) depending upon the engine condition and the altitude at which the test is performed. SUBTRACT 5.5 kPa FOR EVERY 500 METERS ABOVE SEA LEVEL. SUBTRACT ONE INCH FROM THE SPECIFIED READING FOR EVERY 1,000 FEET OF ELEVATION ABOVE SEA LEVEL.

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