Engineering · Diesel — Fuel
White or light-blue smoke from a diesel at idle most often means:
- AOverloading
- BUnburned fuel from misfiring/low temperature, or lube oil entering the chamber✓ Correct
- CExcess scavenge air
- DA blocked exhaust
Explanation
White smoke is atomized unburned fuel (cold cylinder, late injection, low compression); bluish smoke is burning lube oil. Both differ from the soot of black smoke.
Authority: Diesel Engines (USCG engineering topic)
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