2009 Yamaha F40 Outboard Service Manual, Page 55Get this manual
PTT unit
Operation in case of malfunctions
When the fluid pressure in the PTT cylinder exceeds the specified limit, the protection valves (absorber valve pins) and will open to force the fluid out of the cylinder and to return it to the reservoir and avoid damaging the cylinderThe protection valve opens at 25.0 MPa (250.0 kgfcm2, 3625.0 psi)