(1) There is air in the oil pump. This failure usually occurs when a new pump is installed. When a new pump is started, oil should be added to the pump first to lubricate the pump's bearings, plunger and cylinder. Treatment method: When the pump is running, open the fuel filler port of the oil pump, so that the air in the pump is discharged from the filler port.
(2) The oil level of the fuel tank is too low, and the suction pipe is blocked, which makes the pump suction resistance larger, which causes the pump to be empty or the intake pipe section to leak air, and the pump sucks air. Treatment method: add enough oil as required; clean the filter and unblock the air intake duct; check and tighten the connection screw of the oil inlet pipe section.
(3) The oil pump and the motor are improperly installed, that is, the concentricity between the pump shaft and the motor shaft is inconsistent, causing the oil pump bearing to generate noise due to radial forces. Solution: Check and adjust the concentricity between the oil pump and the motor. (4) The viscosity of the hydraulic oil is too large, which reduces the self-priming ability of the pump and the volumetric efficiency. Treatment method: Use hydraulic oil of appropriate viscosity. If the oil temperature is too low, turn on heating.