1990 Johnson Evinrude "ES" 40 thru 55, P/N 507872, Page 292Get this manual
MANUAL RELEASE
1The engine can be manually lowered from tilted position by opening the manual release valve 2When the manual release valve is opened minimum of three turns, hydraulic fluid flows from the bottom of the cylinder, bypasses the UP check valveand into the reservoir 3As the piston moves down, the filter valve and seat opens and allows fluid to flow to the top of the cylinder4When this cycle is complete, the manual release valve must be closed and torqued to 45-55 in Ibs(5-6 Nm) before normal operation can be resumed