Part of the Yanmar Repair Manuals.
The cylinder head on a BY series engine comes off easily enough; putting it back is where guessing gets expensive. The Engine section of this Yanmar service manual takes the head bolt sequence through all five stages, from the first 80 N·m pull to the final angle turns, alongside a special torque chart, service tool listings, and tests and adjustments for the 4BY-150, 4BY-180, 6BY-220, and 6BY-260 marine diesels.
Across 233 pages it also covers the fuel system with flow diagrams and pump testing, cooling, lubrication, turbocharger, starter motor, alternator, and an Electrical and ECU chapter with component tests and a function description of the engine management system. A closing Troubleshooting chapter carries fault charts and trouble codes.
It is a bookmarked PDF (Yanmar publication 0BBY0-G00102) you download once and keep, on the bench laptop or printed a page at a time as the work demands.
Complete the set for your 4BY / 6BY Series
- Operator Manual: Yanmar 4BY, 6BY Operator Manual
- Operator Manual: Yanmar 4BY / 6BY Series Marine Diesel Engines Operator Manual
Other edition of this manual
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 6-7 | Revision History |
| Safety | 8-13 | |
| General Service Information | 14-35 | Safety Precautions, Engine Outline Drawings (4BY with KMH40A, 6BY with KMH40A), Engine Piping Diagrams, Location of Nameplates (Engine Nameplates) |
| Periodic Maintenance | 36-47 | EPA Requirements, Periodic Maintenance Schedule, Periodic Maintenance Procedures |
| Engine | 48-117 | Before You Begin Servicing, Specifications, Special Torque Chart, Special Service Tools, Measuring Instruments, Sealants and Compounds, Tests and Adjustments |
| Fuel System | 118-139 | Safety Precautions, Specifications, Special Service Tools, Fuel System Components, Fuel Flow Diagram, Tests and Adjustments, Repair |
| Cooling System | 140-159 | Before You Begin Servicing, Specifications, Special Service Tools, Measuring Instruments, Cooling Flow Diagram, Tests and Adjustments, Repair |
| Lubrication | 160-171 | Specifications, Special Service Tools, Measuring Instruments, Tests and Adjustments, Repair |
| Turbocharger | 172-179 | Specifications, Special Service Tools, Sealants and Compounds, Tests and Adjustments, Repair |
| Starter Motor | 180-185 | Before You Begin Servicing, Starter Motor Specifications, Starter Motor Troubleshooting, Remove and Install Starter Motor |
| Alternator | 186-191 | Before You Begin Servicing, Specifications, Repair |
| Electrical and ECU | 192-219 | Specifications, Function Description - Engine Management System, Component Tests, Repair |
| Troubleshooting | 220-233 | Engine Faults and Torque Limitations, Troubleshooting Chart, Trouble Codes, After Troubleshooting or Repair |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Cylinder Head Bolt Torque (First Stage) | 80 N·m (59 ft·lb) | p. 75 |
| Cylinder Head Bolt Torque (Second Stage) | Loosen all bolts at least 180° | p. 75 |
| Seawater Pump Impeller Replacement Interval | Every 250 hours or one year, whichever comes first | p. 43 |
| Zinc Anode Torque | 25 N·m (18 ft·lb) | p. 143 |
| Zinc Anode Replacement Interval | Every 250 hours or one year, whichever comes first | p. 43 |
| High-Pressure Fuel Pump Pressure (Min at cranking) | 250 bar (3625 psi) | p. 121 |
| Cooling System Test Pressure | 1.4 bar (20 psi) | p. 143 |
| Thermostat Opening Temperature | 88°C (190°F) | p. 143 |
