A personal watercraft features a four-cycle engine. The four-cycle engine has an intake valve and an exhaust valve. The intake valve and the exhaust valve are controlled through a use of a cam drive arrangement. The cam drive arrangement is contained within a protective housing. A number of waterjackets are provided to the housing to control the temperature within the housing. In addition, the watercraft features a protective housing in which a starter motor is mounted to the cylinder block. The housing features two members that can be mounted to the cylinder block together while one member can be removed for access to the starter motor.