Measure before diagnosing
- Fill to the same safe reference level and record the starting amount.
- Record running hours and the appliances or machines operating during the test.
- Refill to the same level and calculate litres per hour.
- If possible, measure useful electrical energy in kWh. Litres per kWh is more meaningful than litres per hour alone.
Common reasons fuel cost becomes too high
| Cause | What happens | What to check |
|---|---|---|
| Generator is much too large | The engine runs many hours at a very light load. | Compare normal load with rated output. |
| Overload or hard motor starting | Fuel rises while voltage and frequency may fall. | Running load, starting load and breaker trips. |
| Dirty air or fuel system | Combustion becomes inefficient or unstable. | Air filter, fuel filter, fuel quality and injector condition. |
| Long idling or unnecessary running | Fuel is used without useful electrical work. | Operating schedule and shutdown practice. |
| Poor maintenance or engine wear | Compression, injection and control can deteriorate. | Service history, smoke, oil use and technician inspection. |
Practical ways to reduce fuel use
- Select a generator near the real operating requirement while keeping enough starting margin.
- Group useful loads into planned operating periods instead of running the generator for one small load all day.
- Avoid long warm-up, idling and no-load operation beyond the manufacturer's guidance.
- Maintain clean air and fuel filters, correct oil, sound injectors and proper engine speed.
- For long periods of light daily load, compare solar and battery support or a hybrid system.
When high fuel use needs a technician
Need help with your actual equipment?
Send the equipment nameplates, your location and the loads that must run together.