Check oil level and condition:
Possibly the most important aspect of using and maintaining a power washer is checking the engine oil. The oil level should be checked before every use. Most power washer engines have a capacity of less than 2 quarts, with many having a capacity of 1 quart or less. Therefore, even a slight loss of oil through leakage or normal consumption during operation can lead to lubrication issues which could result in increased wear or internal damage to the engine.
Due to the wet environment that most pressure washers are operated in, it is also very important to monitor the oil for signs of moisture contamination.
Many pressure washers have an oil lubricated pump in which the level and condition of the oil should be checked regularly as well.