This manual covers the Volvo Penta 230, 250, and 251 DOHC marine engines, designed for reliable internal combustion engine-based marine propulsion. These engines represent a commitment to robust engineering and dependable performance in demanding marine environments. Their DOHC architecture ensures efficient operation, making them a solid choice for a variety of watercraft applications where power and longevity are paramount. The purpose of this comprehensive Full Service & Repair Workshop Manual is to provide detailed guidance for all repairs, servicing, and troubleshooting procedures. It includes hundreds of pages of step-by-step instructions, accompanied by detailed photos, diagrams, and highly detailed exploded diagrams. This resource is specifically tailored for professional mechanics and technicians, offering the in-depth information required to maintain and repair these Volvo Penta marine engines effectively.