This document provides comprehensive information on the Volvo AQ105 marine engine, identified by engine code 121. This inline 4-cylinder, 2.0-liter gasoline engine, water-cooled and estimated to produce 121 horsepower, is designed for reliable marine propulsion. Its robust engineering reflects Volvo's commitment to quality and performance in marine applications. This Factory Service Repair Manual, presented in English, serves as an essential resource for maintaining and repairing the Volvo AQ105 engine and its associated marine drive. It covers critical areas including detailed maintenance procedures, troubleshooting guidance, technical specifications, and safety protocols. Owners, technicians, and mechanics will find this manual invaluable for ensuring the longevity and optimal performance of their marine power unit.