Running a diesel generator set at low idle speed or no load for 10 minutes can damage the engine. This is because the combustion chamber temperature is too low for the fuel to burn completely. This can lead to carbon buildup around the fuel injector nozzles and piston rings, as well as valve sticking. If the engine coolant temperature drops below 60°C, unburned fuel may wash away the lubricating oil on the cylinder walls and dilute the lubricating oil in the crankcase. The diluted fuel can impair the quality of the lubricating oil and shorten the engine's lifespan. To prevent this, minimize idle time as much as possible.

Diesel generator sets operating at low loads may experience the following five major hazards as operating time increases:

1. Poor piston-cylinder liner sealing, causing engine oil to leak into the combustion chamber and burn, resulting in blue smoke from the exhaust;

2. For turbocharged diesel engines, due to low load or no load conditions, the turbocharger pressure is low. This can lead to a decrease in the sealing effectiveness of the turbocharger oil seal (non-contact type), causing engine oil to leak into the turbocharger housing and enter the cylinder along with the intake air;

3. Some of the oil that enters the cylinder participates in combustion, while some cannot be fully burned, forming carbon deposits on the valves, intake manifold, piston top, and piston rings, and some is expelled with the exhaust. As a result, oil gradually accumulates in the exhaust passages of the cylinder liner, also forming carbon deposits;

4. When engine oil accumulates to a certain level in the turbocharger's charge chamber, it will leak out from the joint surface of the turbocharger;

5. Prolonged operation under low load conditions will exacerbate wear and tear on moving parts, deteriorate the engine's combustion environment, and lead to premature major repairs.　　Therefore, foreign diesel engine manufacturers emphasize that both naturally aspirated and turbocharged models should minimize low-load/no-load operation time, with the minimum load specified as no less than 25%–30% of the unit's rated power.

Operating a diesel generator set at full load for extended periods not only enhances performance and identifies safety hazards but also prevents major accidents.