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Low Altitude

  1. Warm up engine and disconnect vacuum hose between HAC valve and distributor at HAC valve side, and plug hose end. Disconnect vacuum hose from distributor sub-diaphragm, and plug hose end.
  2. Check ignition timing. Timing should be 5° BTDC. Reconnect hose to distributor sub-diaphragm. Check ignition timing. Timing should be about 13° BTDC.
  3. Disconnect vacuum hose from check valve at Black side and plug hose end. Check that ignition timing remains stationary for more than 1 minute. If timing changes, replace check valve. Stop engine and reconnect hoses to proper location.
  4. Disconnect 2 hoses on top of HAC valve. Blow air into each hose and verify that air flows into carburetor. Reconnect hoses to proper locations.
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