1999 Volvo Penta "WT" Models Workshop Manual, Page 174Get this manual
Cleaning Before cleaning the engine, remove the engine accessories to
provide better access to the engine's exterior surfacesAfter
removing the throttle body, distributor, etc cover the openings with tape to prevent the entry of coolant, solvent, or dirtMethods used to clean the engine will depend on what equipment is availableSteam cleaning, pressure washing, or solvent clean-
ing are some acceptable methodsAllow the engine to dry before
beginning the workIt is important that the engine be as clean as possible to prevent dirt from entering critical areas during disassembly