Federal High-Altitude Vehicles
SYSTEM TEST AT LOW ALTITUDES
NOTE: When disconnecting vacuum hoses, mark or label them to ensure proper routing while being reconnected.
The engine must be at operating temperature before running this test.
1. Install a timing light, according to manufacturers' instructions.
2. Remove the air cleaner.
HAC System Test @ Low Altitude For Federal High-Altitude Vehicles:
3. Disconnect the black vacuum hose from the carburetor primary emulsion well bleed nipple. Plug the nipple.
4. Disconnect the red striped vacuum hose from the secondary emulsion well bleed nipple. Plug the nipple.
5. Disconnect the black vacuum hose from the jet air nipple. Plug the nipple.
6. While running the engine at idle, apply vacuum to each hose with a hand vacuum pump.
Vacuum should hold, when applied to each hose.
7. Reconnect the vacuum hoses to their original positions.
Ignition Timing Mark:
8. Run the engine at idle and check ignition timing. The vehicle should be running at BASIC ignition timing.
Refer to SPECIFICATIONS.
HAC System Test @ Low Altitude:
9. While running the engine at idle, disconnect the yellow striped vacuum hose from the HAC. Check for vacuum by placing a finger at the end of the hose.
Vacuum should be felt. Proceed to the High-Altitude Compensator Test.
SYSTEM TEST AT HIGH ALTITUDES
NOTE: When disconnecting vacuum hoses, mark or label them to ensure proper routing while being reconnected.
The engine must be at operating temperature before running this test.
1. Install a timing light, according to manufacturers' instructions.
2. Remove the air cleaner.
HAC System Test @ High Altitude For Federal High-Altitude Vehicles:
3. Disconnect the black vacuum hose from the carburetor primary emulsion well bleed nipple. Do not plug the nipple.
4. Disconnect the red striped vacuum hose from the secondary emulsion well bleed nipple. Do not plug the nipple.
5. Disconnect the black vacuum hose from the jet air nipple. Do not plug the nipple.
6. While running the engine at idle, apply vacuum to each hose with a hand vacuum pump.
Vacuum should leak, when applied to each hose.
7. Reconnect the vacuum hoses to their original positions.
Ignition Timing Mark:
8. Run the engine at idle and check ignition timing. The vehicle should be running at ACTUAL timing. Refer to SPECIFICATIONS.
Compensator Test @ Low Altitude:
HIGH-ALTITUDE COMPENSATOR TEST
Test Procedures to be done if at altitudes below 3,900 ft.
1. Disconnect the yellow striped vacuum hose from the HA Compensator.
2. Connect a hand vacuum pump to the HA Compensator nipple.
3. Apply vacuum. Vacuum should leak.
Compensator Test @ Low Altitude:
4. Disconnect the red striped vacuum hose from the HA Compensator.
5. Connect a hand vacuum pump to the red striped hose nipple.
6. Apply Vacuum. Vacuum should hold.
Compensator Test @ Low Altitude:
HIGH-ALTITUDE COMPENSATOR TEST
Test procedures to be done if at altitudes above 3,900 ft.
1. Disconnect the yellow striped vacuum hose from the HA Compensator.
2. Connect a hand vacuum pump to the HA Compensator nipple.
3. Apply vacuum. Vacuum should hold.
Compensator Test @ High Altitude:
4. Disconnect the red striped vacuum hose from the HA Compensator.
5. Connect a second hand vacuum pump to the compensator, via the red striped vacuum hose nipple.
6. With vacuum being held from step # 3, apply vacuum. Vacuum should leak when applied.
VACUUM SWITCHING VALVE (VSV)
NOTE: When disconnecting vacuum hoses, mark or label them to ensure proper routing while being reconnected.
1. Remove the VSV.
Testing The VSV On High-Altitude Federal Vehicles:
2. Connect a hand vacuum pump to the black vacuum nipple of the VSV.
3. Apply a vacuum of 15.7 in. and check air tightness.
4. Blow in air lightly from the carburetor air bleed side nipple.
Air should not pass through if vacuum applied is less than 7.9 in.
Air should pass through if vacuum applied is more than 9.8 in.
Testing The Check Valve:
CHECK VALVE
NOTE: When disconnecting vacuum hoses, mark or label them to ensure proper routing while being reconnected.
1. Remove the Check Valve.
2. Connect a hand vacuum pump to the check valve and check air tightness.
Vacuum applied to the dark blue side of the check valve, vacuum should leak.
Vacuum applied to the white side of the check valve, vacuum should hold.