A multiple-cylinder engine for a planing water vehicle includes an operation control device which changes the number of deactivated cylinders step by step in response to an engine speed when the engine speed exceeds a preset speed. The operation control device can have a plurality of cylinder deactivation order maps used for instructing an increment order of cylinders which are deactivated step by step when the engine speed exceeds the preset speed. The operation control device can exchange one of the cylinder deactivation order maps which is currently used for another one of the maps in accordance with an operation state of the engine.