Part of the Yanmar Repair Manuals.
The injection pump is where a 2QM15 rebuild gets serious, and this Yanmar service manual (publication 2F015A, 221 pages, English) gives it a full chapter: pump construction, delivery valve checks, nozzle service against the 160 kg/cm2 plus or minus 10 pop pressure, filter and feed pump. From there it works through the whole engine: liner, piston, crankshaft and camshaft limits in Basic Engine, the governor, raw water cooling down to the Kingston cock and anticorrosion zinc, the reduction and reversing gear, and the 12 volt electrical system.
Every afternoon spent bleeding lines or chasing a soft compression stroke is time the engine sits dead in the boat. With the disassembly and reassembly chapter, its tool list, and the tightening torque table, you can take this engine down to a bare block on the stand and bring it back to factory clearances.
What's Inside This Yanmar 2QM15 Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 4-20 | Exterior Views, Specifications, Principal Construction, Performance Curves, Sectional Views, System Diagrams, Standard Accessories |
| Basic Engine | 21-52 | Cylinder Block, Cylinder Liner, Cylinder Head, Piston, Connecting Rod, Crankshaft, Camshaft, Timing Gear |
| Fuel System | 53-69 | Injection Pump, Injection Nozzle, Fuel Filter, Fuel Feed Pump, Fuel Tank (Optional) |
| Governor | 70-78 | Injection Limiter, No-Load Maximum Speed Limiter, Engine Stop Spring |
| Intake and Exhaust System | 79-83 | Intake Silencer, Exhaust System, Breather Pipe |
| Lublication System | 84-91 | Lubrication System, Oil Pump, Oil Filter, Oil Pressure Regulator Valve, Oil Pressure Measurement |
| Cooling System | 92-102 | Water Pump, Thermostat, Anticorrosion Zinc, Kingston Cock, Bilge Strainer |
| Reduction and Reversing Gear | 103-124 | Installation, Operation and Maintenance, Inspection and Servicing, Disassembly, Reassembly |
| Remote Control System | 125-130 | Clutch Regulator One-Handle Remote Control, Decompression Remote Control, Engine Stop Remote Control |
| Electrical System | 131-155 | Composition, Battery, Starter Motor, Alternator, Alarm Circuit |
| Installation and Fitting | 156-171 | Propeller Selection, Engine Installation, Stern Equipment, Interior Piping and Wiring, Front Power Take-Off |
| Operating Instructions | 172-186 | Fuel Oil and Labricating Oil, Engine Operating Instructions, Troubleshooting and Repair |
| Disassembly and Reassembly | 187-214 | Disassembly and Reassembly Precautions, Disassembly and Reassembly Tools, Other, Disassembly, Reassembly, Tightening Torque |
| Inspection and Servicing | 215-220 | Periodic Inspection and Servicing |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Cylinder head tightening nut torque | 15 ~ 16 kg-m | p. 212 |
| Fuel sucked back (delivery valve) | 23.5mm³/stroke | p. 57 |
| Fuel filter element replacement period | Every 100 hours | p. 67 |
| Oil filter replacement period | Every 300 hours of engine operation | p. 89 |
| Secondary oil pressure standard value (Idling) | 0.5 kg/cm² (7.112 lb/in.²) | p. 91 |
| Secondary oil pressure standard value (3,000 rpm) | 2.5 ~ 3.5 kg/cm² (35.56 ~ 49.78 lb/in.²) | p. 91 |
| Compression Ratio | 23:1 | p. 6 |
| Fuel Injection Pressure | 160 ± 10 kg/cm² | p. 6 |
| Battery Voltage | 12 V | p. 144 |
| Alternator Output Current (Standard) | 35A/5000 rpm | p. 144 |
| Connecting Rod Bolt Tightening Torque | 4.5 ~ 5 kg-m | p. 212 |
Yanmar 2QM15 Common Problems This Manual Covers
Loses prime and dies after hours running
Owners regularly report the 2QM15 running fine, then starving and needing a fuel bleed underway, often right at docking. The Fuel System chapter details the injection pump, fuel filter, and feed pump so you can trace where air is entering instead of bleeding the same lines every trip.
Manual Section: Chapter 3 Fuel System p. 53Hard cold starting and low compression
A 2QM15 that cranks well but will not light off cold usually points to worn liners, rings, or valve sealing. The Basic Engine chapter carries the inspection procedures and wear limits for the cylinder liner, piston, cylinder head, and valves needed to find where compression is escaping.
Manual Section: Chapter 2 Basic Engine p. 21Overheating from raw water starvation
A blocked strainer, worn water pump, or spent zinc will cook this engine quietly. The Cooling System chapter covers the water pump, thermostat, anticorrosion zinc, Kingston cock, and bilge strainer so you can work the raw water path end to end.
Manual Section: Chapter 7 Cooling System p. 92Low or erratic oil pressure
Owners chasing odd oil level or pressure readings need real numbers, not guesses. This chapter gives the measurement procedure and standard values, 0.5 kg/cm2 at idle and 2.5 to 3.5 kg/cm2 at 3,000 rpm, plus service of the oil pump, filter, and pressure regulator valve.
Manual Section: Chapter 6 Lublication System p. 84Reversing gear slips or shifts harshly
Clutch wear in the reduction and reversing gear shows up as slip under load or a harsh grab going into gear. Chapter 8 covers construction, inspection and servicing, and full disassembly and reassembly of the gear unit.
Manual Section: Chapter 8 Reduction and Reversing Gear p. 103Governor hunting or surging
Uneven idle and rpm surge trace back to the governor and its related adjustments. Chapter 4 covers the governor itself along with the injection limiter, no-load maximum speed limiter, and engine stop spring.
Manual Section: Chapter 4 Governor p. 70Battery not charging or slow cranking
A tired starter or weak charging circuit leaves the engine dependent on luck. The Electrical System chapter covers the battery, starter motor, alternator, and alarm circuit with test procedures for the 12 volt system.
Manual Section: Chapter 10 Electrical System p. 131Frequently Asked Questions
Which engine does this manual cover?
The Yanmar 2QM15 marine diesel engine, Yanmar publication 2F015A. Its 221 pages run from the basic engine and fuel system through the governor, cooling, lubrication, reduction and reversing gear, remote controls, electrical system, installation, and full disassembly and reassembly.
What is the cylinder head torque for the 2QM15?
The tightening torque table in Chapter 13 Disassembly and Reassembly lists the M14 x 1.5 cylinder head nuts at 15 to 16 kg-m, coated with molybdenum dioxide. The same table covers the connecting rod bolts at 4.5 to 5 kg-m. p. 187
Does it cover the reduction and reversing gear?
Yes. Chapter 8 Reduction and Reversing Gear covers construction, installation, operation and maintenance, inspection and servicing, and step-by-step disassembly and reassembly of the gear unit. p. 103
Is the electrical system and charging circuit included?
Yes. Chapter 10 Electrical System covers the 12 volt battery, starter motor, alternator (standard output 35A at 5000 rpm), and the alarm circuit, including the low oil pressure alarm. p. 131
How will I receive this Service Manual?
This is a 221-page searchable PDF (14 MB) ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Am I able to print pages from this manual?
No restrictions at all. Print individual pages, full chapters, or the entire manual. The PDF is completely unlocked.
Can I find wiring schematics in this Yanmar 2QM15 manual?
Complete wiring diagrams are included, covering all electrical circuits, harness routing, and connector pinouts for the Yanmar 2QM15.
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