Part of the Yanmar Repair Manuals.
Setting valve lash on a 1GM10 or timing the injection pump on a 3HM35 stalls fast without the factory figures, and guessing at a head bolt sequence is how a rebuild goes wrong. This Yanmar service manual (publication 0000 A0A1361) puts the same 474 pages Yanmar's own technicians work from on your bench, covering the GM series marine diesels 1GM10(C), 2GM20(F)(C), 3GM30(F)(C), and 3HM35(F)(C) in both sea-water and fresh-water cooled versions.
Inside are teardown and reassembly procedures for the basic engine, fuel injection system, governor, lubrication system, both cooling systems, and the reduction and reversing gear, plus specifications, cross-sections, and piping diagrams. Chapter 9 even walks through converting a sea-water cooled engine to fresh water cooling.
It downloads as a bookmarked PDF, so the specs travel with you: a laptop at the bench, a phone in the engine bay, or printed pages clipped beside a torn-down block.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| History of Revision | 3 | Safe Servicing Information, Engine Specifications, Manual Content Updates |
| A. Engine Model Name | 9 | |
| B. Engine Model Name Plate and Clutch Model Name Plate | 10-11 | Item Descriptions on Model Name Plates, Information to Be Forwarded to Us, Engine Model Name Plate Location, Clutch Model Name Plate Location |
| Cylinder Number | 12 | Cylinder Numbering Sequence |
| For Safety | 13-18 | 1. for Safe Servicing, Precaution for Safe Servicing |
| General | 19-47 | Specifications, Principal Construction, Performance Curves, Engine Cross-Sections, Dimensions, Piping Diagrams |
| Basic Engine | 48-111 | Cylinder Block, Cylinder Head, Piston, Connecting Rod, Crankshaft, Flywheel and Housing, Camshaft, Timing Gear |
| Fuel System | 112-146 | Fuel Injection System, Injection Pump, Injection Nozzle, Fuel Filter, Fuel Feed Pump, Fuel Tank(Option) |
| Governor | 147-160 | Injection Limiter, No-Load Maximum Speed Limiter, Idling Adjuster, Engine Stop Lever |
| Intake and Exhaust System | 161-168 | Intake Silencer, Exhaust System, Breather |
| Lubrication System | 169-183 | Oil Pump, Oil Filter, Oil Pressure Regulator Valve, Oil Pressure Measurement |
| Direct Sea-Water Cooling System | 184-201 | Cooling System, Water Pump, Thermostat, Anticorrosion Zink, Kingston Cock(Optional), Bilge Pump and Bilge Strainer(Optional) |
| Fresh Water Cooling System | 202-220 | Cooling System, Sea Water Pump, Fresh Water Pump, Heat Exchanger, Filler Cap and Subtank, Thermostat, Cooling Water Temperature Switch, Precautions |
| Modifying the Cooling System | 221-233 | General, Disassembly of Sea Water-Cooled Engine, Assembling Modified Parts to the Fresh Water -Cooled Engine, Cautions When the Engine Is Installed Inboard |
| Reduction and Reversing Gear | 234-333 | [A] for Engine Models 1GM10.2GM20 and 3GM30 (Construction, Shifting Device, Servicing, Disassembly, Reassembly) |
| Remote Control System | 334-341 | Clutch and Speed Regulator Remote Control, Engine Stop Remote Control |
| Electrical System | 342-387 | Battery, Starter Motor, Alternator Standard 12V/55A, Alternator Option 12V/35A, Instrument Panel, Tachometer |
| Operating Instructions | 388-403 | Fuel Oil and Lubricating Oil, Engine Operating Instructions, Troubleshooting and Repair |
| Disassembly and Reassembly (Direct Sea-Water Cooling Engine) | 404-447 | Disassembly and Reassembly Precautions, Disassembly and Reassembly Tools, Disassembly, Reassembly |
| Disassembly and Reassembly (Fresh Water Cooling Engine) | 448-472 | Disassembly of Fresh Water-Cooled Engine, Reassembly of Fresh Water-Cooled Engine, Tightening Torque, Packing Supplement and Adhesive Application Point |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| 1GM10(C), 2GM20(F)(C), 3GM30(F)(C) | ||
| Idling Speed (High) (1GM10(C), 2GM20(F)(C), 3GM30(F)(C)) | 3825 ± 25 min⁻¹ | p. 20 |
| Compression Ratio (1GM10(C), 2GM20(F)(C), 3GM30(F)(C)) | 23.0 | p. 20 |
| 3HM35(F)(C) | ||
| Idling Speed (High), 3HM35(F)(C) | 3600 ± 25 min⁻¹ | p. 20 |
| Compression Ratio, 3HM35(F)(C) | 24.8 | p. 20 |
| 1GM10(C) | ||
| Fuel Injection Pressure, 1GM10(C) | 170 kgf/cm² (2418 lb/in.²) | p. 114 |
| 2GM20(F)(C), 3GM30(F)(C), 3HM35(F)(C) | ||
| Fuel Injection Pressure (2GM20(F)(C), 3GM30(F)(C), 3HM35(F)(C)) | 160 kgf/cm² (2276 lb/in.²) | p. 114 |
