4JH80 and 4JH110
The Yanmar 4JH80 and 4JH110 are compact, turbo‑charged, intercooled four‑stroke diesel auxiliary engines delivering 58.8 kW and 80.9 kW respectively at 3000 rpm, designed for reliable shipboard power generation and propulsion support.
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Common issues
- Fuel system contamination or blockage (filters, injectors) leading to power loss or rough running.
- Raw water pump impeller wear or failure, causing insufficient cooling and potential overheating.
- Heat exchanger fouling (salt/scale build-up) or zinc anode depletion, reducing cooling efficiency.
- Electrical sensor or wiring corrosion/vibration damage, leading to inaccurate readings or control system faults.
- Exhaust manifold/elbow corrosion and leakage, posing a risk of CO poisoning and reduced performance.
- Vibration damper or engine mount degradation, resulting in excessive vibration and potential component fatigue.
- Oil leaks from seals (crankshaft, camshaft) or gaskets (valve cover, oil pan) due to age or vibration.
Inspection checklist
- Check engine oil level and condition (color, viscosity, presence of water/fuel).
- Verify coolant level and condition (color, presence of oil/rust).
- Inspect drive belts for tension, cracks, and wear.
- Check raw water pump for leaks and visually inspect impeller condition (if accessible) or confirm adequate flow.
- Examine the exhaust system for leaks, corrosion, and proper insulation.
- Inspect all hose connections for leaks, chafing, and clamp tightness.
- Assess engine mounts for signs of degradation, cracking, or excessive compression.
- Check electrical connections and wiring for corrosion, chafing, and security.
- Drain fuel filter water separator and inspect fuel filters for contamination.
- Start engine: Observe for abnormal noises, smoke, vibrations, and verify gauge readings (oil pressure, coolant temp, charging voltage).
Service intervals
| Engine Oil & Filter | Every 250 hours or annually, whichever comes first. |
| Fuel Filters (Primary & Secondary) | Every 250-500 hours or annually. |
| Raw Water Pump Impeller | Every 250-500 hours or annually. |
| Air Filter | Every 250-500 hours, clean or replace as needed. |
| Valve Clearance Check | Every 1000 hours. |
| Heat Exchanger Cleaning & Zinc Anode Replacement | Every 500-1000 hours or annually. |
| Coolant Replacement | Every 2000 hours or 2 years. |
| Major Service/Top-End Overhaul | Every 5000-8000 hours (depending on load profile). |
Typical wear limits
| Cylinder Liner Taper/Ovality | Max 0.15 mm (0.006 in) |
| Piston Ring End Gap (Top Ring) | Max 1.2 mm (0.047 in) |
| Crankshaft Main Bearing Clearance | Max 0.10 mm (0.004 in) |
| Valve Stem-to-Guide Clearance | Max 0.15 mm (0.006 in) |
| Fuel Injector Opening Pressure | Within +/- 5% of manufacturer's specification (e.g., 200-220 bar). |
| Turbocharger Radial Play | Max 0.15 mm (0.006 in) (for turbocharged models) |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Engine Oil Filters (x2)
- Fuel Filters (Primary & Secondary, x2 each)
- Raw Water Pump Impeller Kit (impeller, gasket, O-ring)
- Drive Belts (Alternator, Raw Water Pump, x1 each type)
- Zinc Anodes (Heat Exchanger, x2)
- Injector Nozzle (x1)
- Engine Oil (sufficient for one change)
- Coolant (sufficient for top-up)
Safety
- Fuel and oil leaks: High fire risk, especially in machinery spaces.
- Exhaust gas leaks: Risk of carbon monoxide poisoning and burns from hot surfaces.
- Rotating machinery: Entanglement hazard from belts, shafts, and fans.
- Pressurized systems: Risk of injury from sudden release of hot coolant or fuel.
- Electrical system faults: Risk of shock or fire from damaged wiring or components.
Class survey
Verification of engine logbook entries, maintenance records, and spare parts inventory. Operational test including start-up, load response (if possible), and shutdown. Inspection of all safety devices (e.g., overspeed, low oil pressure, high coolant temperature shutdowns) for functionality. Assessment of fuel, exhaust, cooling, and lubrication systems for leaks, corrosion, and integrity. Examination of engine mounts, foundation, and associated pipework for signs of fatigue or degradation. General cleanliness and absence of abnormal vibrations or noises during operation. Confirmation of compliance with DNV MED certificate and IMO requirements.
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
Maintenance per manufacturer manual and classification society requirements. Annual inspection at class survey. Stock spare parts per manufacturer specification.
Suppliers & Spare Parts
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