Looking for the factory procedures to rebuild your Yanmar 2QM15 marine diesel engine? This 221-page Yanmar 2QM15 Service Manual PDF (OEM #2F015A) brings you the exact teardown, inspection, and reassembly data straight from the manufacturer. Open it up to find complete electrical wiring diagrams, fuel system exploded views, and a dedicated troubleshooting section for tracing engine faults. You get step-by-step procedures covering everything from basic cooling system maintenance to a full reduction and reversing gear rebuild. Verify your secondary oil pressure hits 0.5 kg/cm² at idle, and make sure to tighten the cylinder head nuts down to exactly 15 to 16 kg-m during reassembly. Guesswork leads to blown gaskets and dead engines on the water. Grab this bookmarked download, pull it up on your shop tablet, and fix your boat right the first time.
What's Inside This Yanmar 2QM15 Manual
| System | Pages | Key Topics |
|---|---|---|
| Chapter 1 General | 4-20 | Exterior Views, Specifications, Principal Construction, Performance Curves, Features, Sectional Views, System Diagrams, Standard Accessories |
| Chapter 2 Basic Engine | 21-52 | 1.Cylinder Block, 2.Cylinder Liner, 3.Cylinder Head, 4.Piston, 5.Connecting Rod, 6.Crankshaft, 7.Camshaft, 8.Timing Gear |
| Chapter 3 Fuel System | 53-69 | 1.Construction, 2.Injection Pump, 3.Injection Nozzle, 4.Fuel Filter, 5.Fuel Feed Pump, 6.Fuel Tank (Optional) |
| Chapter 4 Governor | 70-78 | 1.Governor, 2.Injection Limiter, 3.No-Load Maximum Speed Limiter, 4.Engine Stop Spring |
| Chapter 5 Intake and Exhaust System | 79-83 | 1.Intake and Exhaust System, 2.Intake Silencer, 3.Exhaust System, 4.Breather Pipe |
| Chapter 6 Lublication System | 84-91 | 1.Lubrication System, 2.Oil Pump, 3.Oil Filter, 4.Oil Pressure Regulator Valve, 5.Oil Pressure Measurement |
| Chapter 7 Cooling System | 92-102 | 1.Cooling System, 2.Water Pump, 3.Thermostat, 4.Anticorrosion Zinc, 5.Kingston Cock, 6.Bilge Strainer |
| Chapter 8 Reduction and Reversing Gear | 103-124 | 1.Construction, 2.Installation, 3.Operation and Maintenance, 4.Inspection and Servicing, 5.Disassembly, 6.Reassembly |
| Chapter 9 Remote Control System | 125-130 | 1.Construction, 2.Clutch Regulator One-Handle Remote Control, 3.Decompression Remote Control, 4.Engine Stop Remote Control |
| Chapter 10 Electrical System | 131-155 | 1.Composition, 2.Battery, 3.Starter Motor, 4.Alternator, 5.Alarm Circuit |
| Chapter 11 Installation and Fitting | 156-171 | 1.Propeller Selection, 2.Engine Installation, 3.Stern Equipment, 4.Interior Piping and Wiring, 5.Front Power Take-Off |
| Chapter 12 Operating Instructions | 172-186 | 1.Fuel Oil and Labricating Oil, 2.Engine Operating Instructions, 3.Troubleshooting and Repair |
| Chapter 13 Disassembly and Reassembly | 187-214 | 1.Disassembly and Reassembly Precautions, 2.Disassembly and Reassembly Tools, 3.Other, 4.Disassembly, 5.Reassembly, 6.Tightening Torque |
| Chapter 14 Inspection and Servicing | 215-220 | 1.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
Yanmar 2QM15 engine runs normally for a few hours and then suddenly quits or loses prime p. 67
Inspect the injector return line routing. Reroute the hose directly back to the tank to prevent a closed circuit that traps air. Replace the secondary fuel filter element every 100 hours as noted on page 67. Bleed the system completely before attempting a restart.
Manual Section: Fuel System TroubleshootingEngine experiences hard cold starting or fails to turn over after sitting overnight p. 57
Check the input fuel lines and check valves for drain-back. Install a new check valve if fuel siphons back while sitting. Verify the delivery valve fuel sucked back amount is 23.5mm³/stroke as specified on page 57. Bleed the lines and test cold start performance.
Manual Section: Fuel System TroubleshootingDipstick shows unexpected high oil level and the gauge displays abnormal oil pressure readings p. 91
Drain excess oil and verify the secondary oil pressure at idling is exactly 0.5 kg/cm² (7.112 lb/in.²) as shown on page 91. Replace the oil filter every 300 hours of engine operation according to page 89. Test the oil pressure alarm operating pressure.
Manual Section: Lubrication System TroubleshootingFrequently Asked Questions
What are the cylinder head torque specs for the 2QM15?
Tighten the cylinder head nuts to 16 kg-m (116 ft-lb). The cylinder head nut is M14 x 1.5 at 15–16 kg-m, and the rocker arm support nut takes 2.0–2.5 kg-m (page 209).
What causes high cooling water temperature on the 2QM15?
Overheating comes from insufficient cooling water, a dirty cooling system, or a faulty thermostat. The alarm activates at 90 ±2°C; normal running temperature is 45–55°C (page 185).
How do I bleed the fuel system on the 2QM15?
Open the fuel tank cock, loosen the air-bleed plug on top of the fuel filter body, and work the fuel pump manual handle until no bubbles appear, then tighten. Bleed the fuel return pipe the same way.
What causes low compression or hard starting on the 2QM15?
Low compression can come from poor intake/exhaust valve sealing, a leaking head gasket, sticking piston rings, or late valve timing. Hard starting can also be caused by bad fuel or a worn starter.
Is this a digital download?
Yes. You get the full 221-page Service Manual as a searchable PDF, ready to download the moment checkout completes. Open it on a computer, tablet, or phone.
Can I print this manual?
Yes. The PDF is DRM-free, so you can print any page or section you need to take out to the shop. Standard letter or A4 paper works.
Document Quality
This document is a high-quality scanned PDF with an OCR layer, allowing you to search and copy the full text. The text is crisp and consistently easy to read on every page. Diagrams and illustrations are clear raster images, with labels generally readable, though some minor pixelation is visible on deep zoom. Pages are clean, free of scan artifacts, stains, or skewed content. You will find several blank pages that act as chapter dividers.
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