6EY22ALW GenSet
The Yanmar 6EY22ALW is a medium‑speed, six‑cylinder inline diesel genset designed for high‑power auxiliary electricity generation on commercial vessels, notable for its dual‑fuel capability (MDO/HFO) and IMO Tier II emissions compliance.
Engine Specifications
Inspector Detail
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Common issues
- Fuel pump element wear due to poor fuel treatment (especially with HFO or contaminated MDO)
- Exhaust valve burning and seat recession, often exacerbated by high exhaust temperatures or poor fuel quality
- Turbocharger fouling (compressor and turbine sides) leading to reduced efficiency and high exhaust temperatures
- Cylinder liner wear exceeding limits, particularly in the upper liner area
- Fuel injector nozzle choking or dribbling, causing poor combustion and high thermal stress
- Bearing wear (main and connecting rod) from lubrication issues or extended service intervals
- Cooling water system blockages or scaling, leading to localized overheating
- Abnormal vibrations or noises indicating imbalance or component wear
Inspection checklist
- Verify all gauge readings (fuel pressure, lube oil pressure, cooling water temperatures, exhaust temperatures per cylinder, turbocharger RPM/boost pressure) against normal operating parameters.
- Check for any visible leaks (fuel, lube oil, cooling water, exhaust gas) around the engine, piping, and flanges.
- Listen for abnormal noises or vibrations from the engine, turbocharger, and generator.
- Inspect exhaust gas color for signs of poor combustion (black smoke), oil burning (blue smoke), or water ingress (white smoke).
- Check fuel oil system for proper operation of heaters, purifiers, and filters, ensuring correct viscosity and pressure at engine inlet.
- Inspect turbocharger for signs of oil leakage, excessive axial/radial play, and cleanliness of air filter.
- Verify proper functioning of all safety devices (overspeed trip, low lube oil pressure shutdown, high cooling water temperature shutdown).
- Examine engine room cleanliness and general condition, paying attention to fire hazards and accessibility for maintenance.
- Review engine logbook for recent alarms, maintenance activities, and trends in operational parameters.
Service intervals
| Daily Checks | Before and during operation (fuel pressure, viscosity, exhaust temps, cooling water temps, visual inspection) |
| Fuel Injector Overhaul | 3,000 - 6,000 operating hours (depending on fuel type and condition) |
| Exhaust Valve Overhaul | 6,000 - 12,000 operating hours (shorter for HFO, longer for MDO) |
| Piston Overhaul (Top Overhaul) | 12,000 - 18,000 operating hours |
| Turbocharger Overhaul | 12,000 - 24,000 operating hours (minor/major overhaul) |
| Major Overhaul (Crankshaft bearings, liners, pistons) | 24,000 - 36,000 operating hours |
| Complete Engine Overhaul | 48,000 - 72,000 operating hours (depending on condition monitoring and previous overhauls) |
Typical wear limits
| Cylinder Liner Wear | Max 0.6 - 0.8 mm increase from original bore diameter (220 mm) |
| Piston Ring Groove Wear | Max 0.15 - 0.20 mm increase in clearance between ring and groove |
| Crankshaft Deflection | Max 0.05 - 0.10 mm (measured between adjacent webs) |
| Exhaust Valve Seat Recession | Max 1.0 - 1.5 mm from original position |
| Main/Connecting Rod Bearing Clearance | Max 0.15 - 0.25 mm (check manufacturer's specific limits) |
| Fuel Pump Plunger/Barrel Clearance | Max 0.005 - 0.010 mm (critical for injection timing and pressure) |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Fuel pump elements (plunger and barrel)
- Exhaust valves and seats/spindles
- Fuel injector nozzles and complete injectors
- Full set of engine filters (fuel, lube oil, air)
- Turbocharger cartridge or bearing kit
- Main and connecting rod bearing shells
- Assorted gaskets and O-rings (especially for fuel and lube oil systems)
- Starting air valve and relief valve spares
Safety
- High-pressure fuel lines (HFO) are susceptible to leaks, posing a significant fire hazard. Ensure spray shields are intact and no leaks are present.
- Hot surfaces: Exhaust manifold, turbocharger, and associated piping can reach extreme temperatures. Ensure insulation is intact and personnel are aware of burn risks.
- Rotating machinery: Generator coupling, flywheel, and fan belts pose entanglement risks. Guards must be in place and secure.
- High voltage: The generator end presents electrocution hazards. Ensure proper lockout/tagout procedures are followed during maintenance.
- Starting air system: High-pressure air (typically 30 bar) requires proper handling and maintenance of valves and piping to prevent ruptures.
Class survey
A class surveyor will typically focus on the overall condition, operational integrity, and compliance with statutory regulations. Key checks include: verification of maintenance records and logbooks; functional testing of all safety devices (overspeed, low lube oil pressure, high cooling water temperature, emergency stop); inspection of fuel oil system integrity (leakage, fire insulation, quick-closing valves); exhaust system integrity (leakage, insulation); general cleanliness and fire prevention measures in the engine room; load test of the generator set to confirm rated output and stable operation; visual inspection for leaks, corrosion, and abnormal wear; and confirmation of valid calibration certificates for critical gauges and sensors.
Components & Design
Component data being added…
Technical Data
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Common failures & inspection points
Type-general inspection and maintenance points for this equipment category — not model-specific.
Service & Maintenance
Daily checks include fuel pressure, viscosity, exhaust temperatures and cooling water temperatures. Carry out Yanmar scheduled overhauls by operating hours.
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