Engineering · Diesel — Fuel
Black smoke from a diesel exhaust most commonly indicates:
- ALube oil burning in the cylinders
- BIncomplete combustion / insufficient air for the fuel injected✓ Correct
- CWater in the fuel
- DCold starting only
Explanation
Black smoke is unburned carbon from incomplete combustion, usually from overload, a dirty air supply, or faulty injection putting in more fuel than the available air can burn.
Authority: Diesel Engines (USCG engineering topic)
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