Part of the Yanmar Repair Manuals.
A BY series engine that cranks clean but will not fire after a filter change is almost always air-locked, and every hour spent guessing is an hour the boat stays tied up. This Yanmar service manual for the 4BY and 6BY marine diesels, publication 0BBY0-G00101, puts the fuel system tests, the flow diagram, and the bleeding warning in front of you.
Across 232 pages it covers periodic maintenance, engine specifications and torque charts, tests and adjustments, plus dedicated sections on the fuel system, cooling system, lubrication, turbocharger, starter motor, alternator, and electrical and ECU, ending in a troubleshooting chart with trouble codes.
For the rebuild itself, the numbers are all here: 84 mm x 90 mm bore and stroke, 16.5:1 compression ratio, cylinder compression of 28 ±2 bar, and the head bolt torque sequence. With nameplate locations and principal specifications, you order the right parts for the engine on your stand the first time.
Complete the set for your 4BY, 6BY
- 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 | 5-6 | Revision History |
| Safety | 7-12 | |
| General Service Information | 13-34 | Safety Precautions, Engine Outline Drawings, Engine Piping Diagrams, Location of Nameplates, Diesel Fuel, Engine Oil, Engine Coolant, Principal Engine Specifications |
| Periodic Maintenance | 35-46 | EPA Requirements, Periodic Maintenance Schedule, Periodic Maintenance Procedures |
| Engine | 47-116 | Before You Begin Servicing, Specifications, Special Torque Chart, Special Service Tools, Measuring Instruments, Sealants and Compounds, Tests and Adjustments |
| Fuel System | 117-138 | Safety Precautions, Specifications, Special Service Tools, Fuel System Components, Fuel Flow Diagram, Tests and Adjustments, Repair |
| Cooling System | 139-158 | Before You Begin Servicing, Specifications, Special Service Tools, Measuring Instruments, Cooling Flow Diagram, Tests and Adjustments, Repair |
| Lubrication | 159-170 | Specifications, Special Service Tools, Measuring Instruments, Tests and Adjustments, Repair |
| Turbocharger | 171-178 | Specifications, Special Service Tools, Sealants and Compounds, Tests and Adjustments, Repair |
| Starter Motor | 179-184 | Before You Begin Servicing, Starter Motor Specifications, Starter Motor Troubleshooting, Remove and Install Starter Motor |
| Alternator | 185-190 | Before You Begin Servicing, Specifications, Repair |
| Electrical and ECU | 191-218 | Specifications, Function Description - Engine Management System, Component Tests, Repair |
| Troubleshooting | 219-232 | Engine Faults and Torque Limitations, Troubleshooting Chart, Trouble Codes, After Troubleshooting or Repair |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Cylinder Head Bolts Torque - First | 80 N·m (59 ft-lb) | p. 54 |
| Cylinder Head Bolts Torque - Second | Loosen all bolts at least 180° | p. 54 |
| Fuel Fine Filter Replacement Interval | Every 250 hours or one year, whichever comes first | p. 39 |
| Fuel Filter / Water Separator Element Replacement Interval | Every 250 hours or one year, whichever comes first | p. 39 |
| Fuel Supply Line Minimum Diameter | 8 mm (0.315 in.) | p. 21 |
| High-Pressure Fuel Line Union Nut Torque | 23 N·m (204 in.-lb) | p. 120 |
| Rubberized Hoses (Fuel and Water) Replacement Interval | Every 500 hours or 2 years, whichever comes first | p. 41 |
| Hose Clamps Torque - 5 mm Hex Head | 1.0 - 1.5 N·m (8.9 - 13 in.-lb) | p. 31 |
| Seawater Pump Impeller Replacement Interval | Every 250 hours or one year, whichever comes first | p. 40 |
| Seawater Pump Belt Replacement Interval | Every 250 hours or one year, whichever comes first | p. 40 |
| Air Filter Element Replacement Interval | Every 500 hours or 2 years, whichever comes first | p. 40 |
| Zinc Anode Torque | 25 N·m (18 ft-lb) | p. 142 |
