Auxiliary Air Valve System
NOTE:
Tachometer must be installed when checking auxiliary air valve system. Tachometer must be connected to proper terminals. See IDLE SPEED & MIXTURE in ADJUSTMENTS
article in the ENGINE PERFORMANCE Section for tachometer connections.
CAUTION:
Some tachometers may not be compatible with ignition system. Consult tachometer manufacturer before connecting tachometer to system. To avoid possible damage to ignitor and/or coil, DO NOT allow tachometer terminal to become grounded.
- Install tachometer. With engine coolant temperature less than 176°F (80°C), start engine.
- With engine idling, turn idle speed adjusting screw inward to bottom of bore while counting number of revolutions. See Fig 1 and Fig 2 . Engine speed should decrease noticeably.
- Return idle adjusting screw to original position. Warm engine to normal operating temperature. Repeat step 2). Engine speed should not change or should drop slightly.
- If engine RPM does not respond as indicated, check for vacuum leaks after the valve or restricted chamber in auxiliary air valve circuit. If no defects are found, replace auxiliary air valve.