Part of the Yanmar Repair Manuals.
Set the cylinder head back on a 2QM20 without the torque figure in front of you and you are gambling a casting that costs many times what this manual does. Yanmar's factory service manual F027A2223 covers the 2QM20, 2QM20H, 2QM20Y and 2QM20F twins and the 3QM30, 3QM30H, 3QM30Y and 3QM30F triples, 349 pages running from the cylinder block out to the reduction and reversing gear.
The numbers a rebuild lives on are here: cylinder head nuts at 18 plus or minus 1.5 kg·m, connecting rod bolts at 5.5 to 6.0 kg·m, injector pop pressure of 160 kg/cm², and thermostat opening temperatures for both the seawater cooled and freshwater cooled versions. Fuel system, governor, lubrication, electrical and full disassembly procedures round it out.
As a PDF it travels: on the bench beside the block, in a locker aboard, or on the phone in your pocket.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 4-43 | Exterior Views, Specifications, Principal Construction, Performance Curves, Engine Cross-Section, Dimensions, System Diagrams |
| Basic Engine | 44-84 | Cylinder Block, Cylinder Liner, Cylinder Head, Piston, Connecting Rod, Crankshaft, Camshaft, Timing Gear |
| Fuel System | 85-106 | Injection Pump, Injection Valve, Fuel Filter, Fuel Feed Pump, Fuel Tank (Option) |
| Governor | 107-115 | Injection Limiter, No-Load Maximum Speed Limiter, Idling Adjuster |
| Intake and Exhaust System | 116-122 | Intake Silencer, Exhaust System, Breather Pipe, Intake Manifold [3QM30(H)] |
| Lubrication System | 123-134 | Oil Pump, Oil Filter, Oil Pressure Regulator Valve, Oil Pressure Measurement |
| Cooling System | 135-162 | Sea Water Cooling (Cooling System, Water Pump and Bilge Pump, Thermostat, Anticorrosion Zinc, Kingston Cock, Bilge Strainer) |
| Chain-Overdrive Hand-Operated System | 163-166 | |
| Reduction and Reversing Gear | 167-223 | For Model 2QM20, 3QM30 (Construction, Installation and Operation, Handling the Reduction and Reversing Gears, Servicing, Disassembly, Reassembly) |
| Remote Control System | 224-232 | Clutch and Speed Regulator Remote Control, Decompression Remote Control, Engine Stop Remote Control |
| Electrical System | 233-262 | Composition, Battery, Starter Motor, Alternator, Alarm Circuit |
| Installation and Fitting | 263-291 | Propeller Selection, Engine Installation, Stern Equipment, Interior Piping and Wiring, Front Power Take-Off |
| Operating Instructions | 292-307 | Fuel Oil and Lubricating Oil, Engine Operating Instructions, Troubleshooting and Repair |
| Disassembly and Reassembly | 308-341 | Disassembly and Reassembly Precautions, Disassembly and Reassembly Tools, Other, Disassembly, Reassembly, Tightening Torque, Packing Supplement and Adhesives |
| Inspection and Servicing | 342-348 | Periodic Inspection and Servicing |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Delivery valve holder tightening torque | 4 ~ 4.5 kg·m (29 ~ 32.6 lb·ft) | p. 95 |
| Injection pressure | 160 kg/cm² (2,270 lb/in.²) | p. 102 |
| Thermostat opening temperature (sea water cooling) | 42°C | p. 143 |
| Thermostat full open temperature (sea water cooling) | 52°C | p. 143 |
| Oil filter replacement period | Every 300 hours of engine operation | p. 132 |
| Fuel filter cleaning period | Every 50 hours | p. 104 |
| Fuel filter element replacement period | Every 100 hours | p. 104 |
| Cylinder head packing agent and adhesive | Three Bond No. 4, Three Bond No. 50, Screw Lock Super 203M | p. 341 |
| Cylinder block packing agent and adhesive | Three Bond 388-005 | p. 341 |
| Corrective action for thermostat faulty (cooling water temperature high) | Replace thermostat | p. 307 |
| Bore × Stroke | 88 × 90 mm | p. 9 |
| Displacement | 1088 cc | p. 9 |
