1990 Johnson Evinrude "ES" 40 thru 55, P/N 507872, Page 289Get this manual
1 Component Description
CHECK VALVEWhen opened by pump pressure, it directs fluid to bottom of cylinder to move piston UPWhen opened by pump control piston, it allows low pressure fluid to return to the pump as the piston moves DOWN
f21 DOWN CHECK VALVEWhen opened by pump pressure, it
directs fluid to top of cylinder to move piston DOWNWhen opened by pump control piston, it allows low pressure fluid to return to the pump as the piston moves UP20860
PISTONMoved by pump pressure, it controls the UP and DOWN check valvesTogether, they control fluid direction and cylinder movementMANUAL RELEASE VALVEWhen opened minimum of three turns, it allows cylinder fluid to bypass the UP check valve and return directly to the reservoirThe engine can be lowered manually when the MANUAL RELEASE VALVE is open The MANUAL RELEASE VALVE has integral expansion relief to protect the unit from extreme pressures caused by thermal expansion of the fluid