Part of the Yanmar Operator Manuals.
An alarm sounds at cruising rpm, the panel shows a code, and nothing at the helm tells you what it means. That moment is why the Troubleshooting section of this manual earns its place: pages 65 to 74 hold the troubleshooting chart and the diagnostic trouble codes for Yanmar's electronically controlled BY series.
The rest of the 88 pages cover the 4BY2 and 6BY2 marine diesels built from 2006 to 2009, per Yanmar publication 0ABY0-G00200. Inside are the periodic maintenance schedule with its 250-hour service items, specifications for diesel fuel, engine oil, coolant, power steering fluid, and marine gear or stern drive oil, starting and shutdown procedure, fuse and relay locations, and long-term storage preparation.
It is a searchable English PDF, easy to print page by page before the next oil change or impeller swap. Specifications for both engines, including oil and coolant capacities, begin on page 77.
What's Inside This Yanmar 4BY2, 6BY2 Operator Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 7-8 | Record of Ownership |
| Safety | 9-14 | Safety Precautions (Before You Operate, During Operation and Maintenance), Safety Decals |
| Product Overview | 15-26 | Yanmar BY-Series Features and Applications, Component Identification, Location of Nameplates, Major Components, Fuses and Relays, Engine Cover |
| Before You Operate | 27-38 | Diesel Fuel, Engine Oil, Marine Gear or Stern Drive Oil, Power Steering Fluid Specifications, Engine Coolant |
| Engine Operation | 39-42 | Starting the Engine, Shutting Down the Engine, Checking the Engine After Operation |
| Periodic Maintenance | 43-64 | Safety Precautions, Precautions, EPA Requirements, Periodic Maintenance Schedule, Daily Checks, Periodic Maintenance Procedures |
| Troubleshooting | 65-74 | Troubleshooting Information, Troubleshooting Chart, Diagnostic Trouble Codes |
| Long-Term Storage | 75-76 | Prepare Engine for Long-Term Storage |
| Specifications | 77-80 | Engine Specifications |
| EPA Warranty Usa Only | 81-88 | Yanmar Co., Ltd. Limited Emission Control System Warranty - Usa Only |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Hose Clamp Torque (5mm Hex Head) | 1.0 - 1.5 N·m (8.9 - 13 in.-lb) | p. 47 |
| Fuel Filter / Water Separator Element Replacement Interval | Every 250 hours or one year, whichever comes first | p. 49 |
| Fuel Filter / Water Separator Element Torque (filter bowl) | Turn clockwise by hand to tighten | p. 58 |
| Fuel Filter / Water Separator Drain Plug Tightening | Securely tightened | p. 58 |
| Seawater Pump Impeller Replacement Interval | Every 250 hours or one year, whichever comes first | p. 49 |
| Seawater Pump Impeller Replacement Interval (Long-Term) | Every 2000 hours of operation or every 8 years, whichever comes first | p. 63 |
| Rubber Hoses (water) Replacement Interval | Every 250 hours or one year, whichever comes first | p. 51 |
| Hose Clamp Torque (6mm Hex Head) | 2.5 - 3.5 N·m (22 - 31 in.-lb) | p. 47 |
| Rubber Hoses (fuel) Replacement Interval | Every 250 hours or one year, whichever comes first | p. 51 |
| Air Filter Element Replacement Interval | Every 250 hours or one year, whichever comes first | p. 49 |
| Alternator Belt Check/Replacement Interval | Every 250 hours or one year, whichever comes first | p. 49 |
Yanmar 4BY2, 6BY2 Common Problems This Manual Covers
Check-engine alarm under way
A warning at higher rpm can come from something as small as a loose vacuum hose or as serious as low oil pressure. The Troubleshooting section pairs a symptom chart with the diagnostic trouble codes so you can identify the trigger before restarting.
Manual Section: Troubleshooting p. 65Water in the fuel separator
Common rail injection does not forgive water in the fuel. The manual covers draining the fuel filter and water separator and replacing the element every 250 hours or one year, whichever comes first.
Manual Section: Periodic Maintenance p. 43Overheating from a worn impeller
A tired seawater pump impeller sheds vanes and starves the cooling circuit. The maintenance schedule calls for impeller replacement every 250 hours or one year, and the procedures walk you through the periodic checks that catch it early.
Manual Section: Periodic Maintenance p. 43Wrong oil or coolant in the engine
Guessing at fluids is how bearings and heat exchangers die young. This section gives the specifications for diesel fuel, engine oil, engine coolant, power steering fluid, and marine gear or stern drive oil so every fill is to Yanmar's requirement.
Manual Section: Before You Operate p. 27Dead gauge or blown fuse
Electrical faults on these engines often start at a fuse or relay, and the job stalls when you cannot find the right one. The Product Overview identifies fuses, relays, and major components with their locations.
Manual Section: Product Overview p. 15Corrosion after winter layup
An engine parked wet over the off season comes back with seized parts and sour fuel. The Long-Term Storage section gives the preparation steps to lay the engine up properly.
Manual Section: Long-Term Storage p. 75Frequently Asked Questions
Which engines does this manual cover?
The Yanmar 4BY2 and 6BY2 marine diesel engines, 2006 to 2009, publication 0ABY0-G00200. The Specifications section lists both models separately, including engine oil capacity (8.0 L for the 4BY2, 11.0 L for the 6BY2) and coolant capacity (10 L and 13 L). p. 77
Does it explain the diagnostic trouble codes?
Yes. The Troubleshooting section, pages 65 to 74, includes troubleshooting information, a symptom-based troubleshooting chart, and the diagnostic trouble codes for these electronically controlled engines. p. 65
What service intervals does the Yanmar 4BY2, 6BY2 manual give?
The Periodic Maintenance section sets the full schedule. On the 250 hour or one year interval, whichever comes first: the fuel filter and water separator element, the seawater pump impeller, the air filter element, the alternator belt, the rubber fuel and water hoses, and the sacrificial anodes (page 50) - check the anodes periodically and replace any that has less than half its original size left. Long life coolant goes every two years, and daily checks are listed separately. p. 43
Is this a full workshop or rebuild manual?
No. This is the factory operator manual, covering operation, fluids, periodic maintenance, troubleshooting, storage, and specifications. It does not include internal rebuild data such as bearing clearances or a cylinder head torque sequence, so buy it for running and maintaining the engine, not tearing it down.
What format is this manual in?
A 88-page Operator Manual in searchable PDF format, available the moment you complete checkout. View on computer, tablet, or phone, with no shipping wait.
Does this Yanmar 4BY2 manual allow printing?
No restrictions at all. Print individual pages, full chapters, or the entire manual. The PDF is completely unlocked.
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