I. Generator Engine Overhaul
What It Is
The engine is completely disassembled, and every component is inspected, measured, repaired, or replaced. This is not a repair focused solely on the failed part.
When to Perform
l Oil consumption exceeds 1% of fuel consumption
l Significant power loss under load
l Cylinder pressure is 20% below the standard value
If two of the above conditions are present, an overhaul should be scheduled.
How to Perform
Disassemble → Clean → Measure → Repair → Replace → Assemble → Test. Bore the cylinder block to fit oversized pistons; grind the crankshaft to fit undersized bearings. All wear-prone parts are replaced with new ones. After assembly, test power output, fuel consumption, and exhaust temperature on a dynamometer.
How the Policy Applies
Imported components are sourced through bonded channels in Hainan, China, with no tariffs and no tied-up capital.
II. Diesel Engine Repair Services
What They Are
Tiered maintenance performed proactively, rather than waiting for a failure.
When to Perform
l 250 hours: Change engine oil and oil filter, change fuel filter, clean air filter
l 500 hours: Additionally inspect valve clearance, fuel injectors, turbocharger
l 1,000 hours: Additionally measure cylinder compression, crankshaft clearance, bearing clearance
How to Perform
Maintenance is carried out based on operating hours, whichever interval is reached first. For equipment with low running hours, follow the calendar-based schedule, as oil degrades over time.
How the Policy Applies
Consumables such as imported filters and imported oil can be procured at lower cost through bonded channels in Hainan, China.
III. Generator Troubleshooting
What It Is
A systematic, system-by-system approach without disassembling components randomly.
How to Perform
1. Starting system: Check battery voltage, terminal tightness, relay engagement
2. Fuel system: Check fuel level, valve position, air in fuel lines
3. Compression system: Check cylinder compression and variation between cylinders
4. Electrical system: Check excitation resistance, diodes, carbon brushes, AVR
Acceptable Standards
l 12V battery: no less than 10V; 24V battery: no less than 20V
l Cylinder compression: 2.5–3.0 MPa, with variation between cylinders not exceeding 8%
l Excitation resistance: 2–6 Ω; carbon brush length: no less than 10 mm
How the Policy Applies
If an imported component is identified as the issue during generator troubleshooting, it can be replaced through bonded channels in Hainan, China.
IV. Generator Performance Testing
What It Is
Using data to assess equipment condition rather than relying on subjective judgment.
What to Test
l Insulation resistance: Cold state >5 MΩ, hot state >1 MΩ, polarization index >1.3
l Voltage regulation: Variation from no load to full load < ±2.5%
l Frequency regulation: Variation from no load to full load < ±3%
l Three-phase balance: Unbalance at no load < 3%
When to Test
Testing is mandatory after an overhaul. Under normal conditions, test once per year, or whenever performance is suspected to have degraded.
How the Policy Applies
Test equipment and calibration instruments can be imported more conveniently through bonded channels in Hainan, China.
V. Why a Diesel Generator Won’t Start
What to Check
Follow a sequence of seven checkpoints without backtracking unnecessarily.
Sequence
1. Battery: Sufficient voltage? Terminals tight?
2. Fuel: Fuel present? Valve open? Air in fuel lines?
3. Preheating: On cold days, feel whether the glow plugs are warm
4. Starter motor: Cranking speed? Carbon brush length?
5. Safety protection: Are any alarm indicators lit?
6. Governor: Is the sensor gap correct?
7. Fuel injectors: Is the injection pulse pattern clearly visible?
Acceptable Standards
l Battery: 12V ≥10V / 24V ≥20V
l Glow plugs: Should feel warm to the touch
l Sensor gap: 0.8–1.2 mm
How the Policy Applies
If the seven-step diagnosis determines that an imported component is the cause of why a diesel generator won’t start, replacement parts can be sourced through bonded channels in Hainan, China.
Obtain Cost-Effective Generator Maintenance Solutions – Start Today
Are you seeking reliable and affordable diesel generator maintenance services? Contact us today to learn more about our generator repair services, diesel engine repair services, generator overhaul services, and bonded maintenance solutions available in China's Hainan Free Trade Port. With our professional support, you can reduce maintenance costs, enhance operational efficiency, and ensure the long-term reliability of your equipment.