Cold oil.

Allow oil to warm up before operating machine.

Oil viscosity too heavy.

Use oil recommended by the manufacturer.

Insufficient engine speed.

Refer to operator’s manual for recommended speed. If machine has a governor, it may need adjustment.

Low oil supply.

Check reservoir and add oil if necessary. Check system for leaks that could cause loss of oil.

Adjustable orifice restricted too much.

Back out orifice and adjust it. Check machine specifications for proper setting.

Air in system.

Check suction side of the system for leaks.

Badly worn pump.

Repair or replace pump. Check for problems causing pump wear such as misalignment or contaminated oil.

Restriction in suction line or filter.

Suction line could be dirty or have inner walls that are collapsing to cut off oil supply. Clean or replace suction line. Examine filter for plugging.

Relief valves not properly set or leaking.

Test relief valves to make sure they are opening at their rated pressure. Examine valves for damaged seats that could leak.

Badly worn components.

Examine and test valves, motors, cylinders, etc. for external and internal leaks. If wear is abnormal, try to locate the cause.

Valve or regulators plugged.

Clean dirt from components. Clean orifices. Check for source of dirt and correct.

Oil leak in pressure lines.

Tighten fittings or replace defective lines. Examine mating surfaces on couplers for irregularities.

Components not properly adjusted.

Refer to machine technical manual for proper adjustment of components.