Fault Phenomenon: Sumitomo crawler crane engine emits black smoke, slow acceleration, unable to reach rated RPM.

Troubleshooting Process:
– Checked air filter: severely clogged.
– Checked injector nozzles: poor atomization.
– Replaced air filter and cleaned/calibrated injector nozzles.

Root Cause: Intake system blockage caused incomplete combustion, combined with injector nozzle issues.

Required Parts: Air filter element, injector nozzle repair kit.