The inner surface of the centrifugal pump and the inner surface of the pressurized water chamber are rusty. Surface rust will reduce the pump water 7% -8%; maintenance only with steel brush and iron sandpaper or grinding wheel smooth, you can make it in the work of the fuel consumption or power consumption reduced by 9% -14%. Seal ring gap increases. 
According to the test, when the impeller radius in the direction of the gap increased by 4 mm, the pump will be reduced by 10%; maintenance only with organic adhesive plus asbestos line to restore the factory to the provisions of the gap, you can make the pump at work fuel consumption or Power consumption reduced by 10% -12%. The axis of the water chamber and the impeller does not coincide. According to the test, when the pressure chamber and the impeller axis deviation of 2 mm or skew angle greater than 2 degrees, the pump water will be reduced by 5% -6%; maintenance, just careful measurement, carefully identify the axis coincidence position, You can make the pump at work when the oil or power consumption reduced by 6% -7%. Blade installation angle is inconsistent. When the blade installation angle is inconsistent, the pump water will be reduced by 5%; maintenance, the use of angle scale, the installation of fixed position, you can make the pump at work fuel consumption or power consumption reduced by 5% -6%.