TOHATSU MFS 8B Service Manual page 228

The PT unit is provided with a shock absorber that protects the drive unit from an impact in case it hits underwater obstacle
during cruising.
In case drive unit hits an underwater obstacle, the hydraulic pressure in the cylinder upper chamber is increased suddenly.
The high pressure opens shock valve of piston.
When shock valve opens, oil in the cylinder upper chamber flows into the lower cylinder chamber to extend tilt rod upward to
absorb the shock.
7-34 4st 8/9.8 2016