Mazda 6 Service Manual: No.6 cranks normally but will not start

No.5 engine stalls-after start/at idle

No.7 slow return to idle

Other materials:

Mazda 6 Service Manual: Generator removal/installation
Warning When the battery cables are connected, touching the vehicle body with generator terminal B will generate sparks. This can cause personal injury, fire, and damage to the electrical components. Always disconnect the battery negative cables before performing the following operation. ...

Mazda 6 Service Manual: Starting a Flooded Engine
If the engine fails to start, it may be flooded (excessive fuel in the engine). Follow this procedure: 1. If the engine does not start within five seconds on the first try, wait ten seconds and try again. 2. Make sure the parking brake is on. 3. Depress the accelerator all the way and hold it ...