Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Is oil foamy? And bubbles in the tank? The pump is sucking air into the system or the oil supply to pump is restricted, letting it aerate. Check the suction hose and clamps, and replace the hydraulic filter.
Only place air can enter is before and up to the pump. Can be any connection or a fitting . But it has to be on the suction side of the pump.