1997 Johnson Evinrude "EU" Accessories Service Manual, P/N 507270, Page 120Get this manual
Trim-OUTITilt-UP Mode
When operating the hydraulic unit in the trim-outtilt-up mode, hydraulic fluid is routed in the following manner:
1Hydraulic pressure is directed to the trim check valve side of the pump control pistoncausing the piston to open the reverse lock check valve 2Fluid then opens the trim check valve against very light spring tension, and the fluid flows to the base of the trim cylinders3Additional hydraulic fluid opens the tilt check valve and flows to the base of the tilt cylinder4Fluid returning from the top of the trim and tilt cylinders is directed through the open reverse lock check valve and back to the pumpIt is important to note that all fluid on the return path returns to the pumpBecause the trim and tilt rods displace fluid at the top of the cylinders, the fluid returning to the pump through the reverse lock check is not sufficient to supply the pump, so additional fluid is drawn from the reservoir5When both the trim and tilt rods are fully extended and the pressure exceeds 1500 PSI (10500 kPa), the trim-up relief valve will open, directing the fluid to the reservoir6When the hydraulic unit is trimming outtilting up, or when the engine is running in forward gear, the following components must hold pressure: Trimtilt separation valve Trim check valve Expansion relief valve Trim cylinder O-rings Trim-up relief valve Tilt check valve Tilt cylinder piston and O-ring