Chapter One General Information This Clymer shop manual covers the GM Yanmar ma- rine diesel engine series identified in Table 1. Troubleshooting, tune-up, maintenance and repair are not difficult, if you know what tools and equipment to use and what to do. Step-by-step instructions guide you through jobs ranging from simple maintenance to com- plete engine overhaul. This manual can be used by anyone from a first-time do-it-yourselfer to a professional mechanic. Detailed drawings and clear photographs provide all the informa- tion needed to do the work right. Some ofthe procedures in this manual require the use of special tools.
The resourceful mechanic can, in many cases, think of acceptable substitutes for special tools. However, using a substitute for a special tool is not recom- mended, as it can be dangerous and may damage the part. If a tool can be designed and safely made, but will require some type of machine work, contact a local community college or high school that has a machine shop curricu- lum. Shop teachers sometimes welcome outside work that can be used as practical shop applications for students. Each Yanmar marine diesel can be identified by its indi- vidual model number. The model numbers for all Yanmar marine diesel engines covered in this manual are listed in Table 1.
Some engine model numbers end with the letters ForD, such as 2GMF or 3GMD. Suffix letter F indicates the en- gine is equipped with a freshwater (closed) cooling sys- tem. Suffix letter D indicates the engine is equipped with a Kanzaki KBWlOD transmission. Except where specified, F and D series engines are in- cluded when a basic model number is specified. For ex- ample, if model 3GM is called out in a procedure, the procedure also applies to 3GMD and 3GMF. NOTE Engine models ending with the letters C (sail drive) or V (V-drive transmission) are not covered in this manual. Metric and U.S. standards are used throughout this manual. U.S. to metric conversions are in Table 2.
Critical torque specifications are provided at the end of each chapter (as required). Use the general torque specifi- cations listed in Table 3 if a torque specification is not listed for a specific component or assembly. Metric drill tap sizes are in Table 4. Tables 1-4 are located at the end of the chapter. MANUAL ORGANIZATION This chapter provides general information useful to en- gine owners and mechanics. In addition, this chapter dis-