MARINE GEAR- MAINTENANCE INSTRUCTION (Cont.)
Metal piston rings, which function as oil seals, are used in the clutches. The metal rings prove
superior to other types of seals normally used in marine gear clutches. All oil that passes through the hydraulic
system is subjected to two full-flow type filters. The oil return pipe assembly regulates the low pressure oil
supply and also distributes oil for lubrication purposes. A heat exchanger is installed in the hydraulic system to
maintain the oil within the marine gear at the recommended temperature.
External Oil Circuit. Oil is dr awn from the sump through the oil strainer to the oil pump assembly.
From the oil pump assembly, the oil is conveyed by a flexible hose to the oil filter. The filtered oil is routed
from the filter to a remote-mounted heat exchanger. The cooled oil from the heat exchanger is routed to a
reduction "tee" fitting on the selector valve. The "tee" fitting on the selector valve has a pipe plug which should
be removed and replaced by a pressure gage or connecting line to a pressure gage. Pressure reading at this
point will be "clutch-apply pressure" oil.