1991 Johnson/Evinrude EI 60 thru 70 outboards Service Manual, Page 285Get this manual
Tilt Relief 1If the recommended RPM is exceeded while operating the motor in the shallow water drive mode, increased pressure beneath the tilt piston opens the tilt relief valve built into the manual release valve 2Fluid flows from below the tilt piston, through the tilt relief valve and to the reservoir3As the tilt piston moves down, the filter valve opens and allows fluid to flow from the reservoir to the top of the tilt cylinder4The motor will tilt down to the top of the trim range