1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 388Get this manual
Striking an Underwater Object
When an underwater object is hit, the shock absorber will absorb the shock and allow the motor to til up The tilt piston will be pulled in an upward motion1The shock absorber valves in the tilt cylinder piston open and allow the fluid at the top of the piston to flow to the bottom2At the same time that the ilt rod is being extendedthe rest of the hydraulic unit is being set up for the return to water function 3High pressure fluid opens the impact sensor valve 175 kg cm (17,230 kPa) (2,500 psi) 4Fluid passing through the impact sensor valve causes the letdown control piston to move and open the impact letdown valve 5When the tilt cylinder piston stops moving outwardthe impact sensor valve closes, keeping the letdown control piston pressurized, which in turn keeps the impact letdown va Ive openImmediately after the impact sensor valve closes, the letdown control piston begins to "leak down" at predetermined rate