Mariner 30 JET 40 (4 CYL) Service Manual page 399

Shock Function Return
After the drive clears the object, the shock return
valve (o) will allow the oil to flow from between the
shock piston (n) and memory piston (m) onto the
down cavity as the drive returns to its original running
position.
90-814676R1 DECEMBER 1996 MID-SECTION - 5G-15