The aim of this paper is to show particular sensitivity of the flow part of the marine turbine engine to the presence of contaminants in the intake air. The contaminants form hard-to-remove deposits in the intervane channels that result in a reduced efficiency and performance of the engine. The paper classifies the contaminants according to the source of their formation and their destructive force. The performed analyses and syntheses of the discussed problem have been complemented with the results of own endoscopic research of the flow part of various types of marine turbine engines.