If the filter element of the air filter is too dirty, air intake will be seriously affected and the power of the engine will be decreased and engine performance will be reduced. Dismantle air filter housing to check the air filter, clean or replace dirty or damaged air filter element. If there is oil-bath air filter, check the oil level. Please clean air filter every 50 hours and replace the foam and paper filter element on the air filter every 100 hours or every 6 months. 
1. Cleaning paper filter element
Please slightly tap the filter element on hard plane for several times to remove dust accumulated on it, and then blow from inside to outside with compressed air whose pressure is no more than 207KPa. Please replace the filter element in time if the filter element is too dirty or broken. 
2. Cleaning foam filter
The foam filter can be rinsed in hot water with detergent or can also be cleaned in non-inflammable or high-flash-point solvent; after it is dried, immerse it into clean engine oil, knead evenly and squeeze out engine oil in excess. 
3. Cleaning the oil-bath air filter
Please replace the engine oil in time if it is too dirty. Evacuate the engine oil in the air filter; thoroughly clean the accumulated dust in the air filter with non-inflammable or high-flash-point solvent, dry the air filter box and pour into the same lubricating oil as gasoline engine until it reaches the oil level mark.