This workshop service repair manual covers the Volvo Penta 251DOHC, an internal combustion engine featuring a Double Overhead Camshaft (DOHC) configuration. While specific production years and detailed specifications such as displacement, power output, fuel system, and cooling system are not provided, the Volvo Penta brand is associated with robust engineering and reliability, often applied in marine or industrial settings. This manual is designed to provide comprehensive support for this particular engine model. The purpose of this English-language manual is to offer complete service and repair information. It includes detailed procedures for maintenance, service intervals, oil capacity, and troubleshooting, supported by detailed illustrations. This resource is intended for owners, mechanics, and technicians, enabling them to effectively maintain, diagnose, and repair the Volvo Penta 251DOHC engine, ensuring its optimal performance and longevity.