1978 Johnson 175, 200, 235 HP Outboard Service Manual, Page 175Get this manual
RETURN TO WATER (See Figure 9-5) aThe weight of the motor drives the tilt rod and piston downward, forcing oil from the bottom of the cylinder through the open impact letdown valve and to the reservoir bThe filter valve is opened and allows oil from the reservoir to flow to the top of the cylindercThe letdown control piston leaks down, allowing the impact letdown valve to close