Marine diesel black smoke and low RPM: air, prop or turbo

Applies to: Volvo Penta D3, MD22 and other marine diesels

Symptoms

  • Black smoke under load
  • Won't reach rated RPM at wide open throttle
  • Higher fuel use

Why it happens

The engine is overloaded or short of air: a fouled hull or prop, a clogged air filter, or a dirty turbo or intercooler.

How to fix it

  1. Check the air filter and engine room ventilation.
  2. Inspect the hull and prop for growth or damage.
  3. Check turbo for oil leaks and free spinning.
  4. Clean the intercooler/aftercooler per the manual and check injectors if smoke persists.

Tools and parts

  • Air filter
  • Tachometer

What the factory service manual covers

Air intake and turbo, injector tests, rated RPM and performance specs. The full procedure, specs and wiring diagrams are in the factory service manual for your machine.

Get the factory service manual

Back to blog