High Altitude Check
- Warm up engine and check ignition timing at idle. Disconnect vacuum hose from distributor sub-diaphragm and plug hose end.
- Check that ignition timing remains stationary for more than 1 minute. Stop engine and reconnect hose to check valve.
- Disconnect 2 hoses on top of HAC valve. Blow air into each hose and check that air flows into carburetor. Reconnect hoses to proper locations.