Low intake manifold pressure; black smoke and loss of power; turbo boost below expected.

Safety: Allow turbocharger to cool before touching. Hot surfaces can burn.

• Inspect air filter: Replace a dirty or collapsed air filter with a Volvo Penta-approved element.
• Check charge air hoses: Examine hoses and clamps between turbo, intercooler, and intake manifold for splits, loose clamps, or oil-soaked soft spots. Tighten or replace as needed.
• Spin turbo by hand: With intake hose removed and engine off, gently spin the turbo compressor wheel. It should rotate freely without scraping. Excessive play or binding indicates a failing turbo that must be replaced.
• Test boost sensor: Inspect the manifold pressure sensor and its connector. Clean and reseat. Compare sensor readings to spec using diagnostics; replace if faulty.