This manual covers the Yanmar 4TNV98-YTBL and 4TNV106T-XTBL internal combustion engines, designed for use in Gehl CTL60/80 and Mustang MTL16/25 Track Loaders. These engines represent a commitment to robust engineering and reliable performance, essential for demanding operational environments. The manual details various components, including the cylinder block, cylinder head, fuel injection systems, lubrication and cooling systems, and starting and charging components. It also specifies optional parts for the 4TNV106T-XTBL model, such as the turbine and lubrication oil line. The purpose of this English-language Illustrated Master Parts List is to provide comprehensive information for identifying and ordering parts for these Yanmar engines. It serves as an indispensable resource for owners, mechanics, and technicians, offering detailed illustrations and part numbers for a wide array of components. By utilizing this manual, users can ensure the proper maintenance and repair of their equipment, maximizing operational efficiency and longevity.