Land Cruiser

Warm up engine. Disconnect vacuum hose from the distributor sub-diaphragm and plug hose end. Check ignition timing at idle. Ignition timing should be 7 degrees BTDC. See Fig 1. Reconnect hose to sub-diaphragm. Verify that timing mark on flywheel advances to 6 degrees.

Fig 1: Ignition Timing Mark (Land Cruiser)
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Disconnect the vacuum hose from Black side of check valve. Plug end of hose. Ignition timing must remain stationary for more than one minute. If timing changes, replace check valve. Stop engine and reconnect hose to check valve.

Fig 2: HAC System (Land Cruiser)
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Disconnect 3 hoses on top of HAC valve. Blow air into each hose and check that air flows into carburetor. Reconnect hoses to proper locations.