2009 Yamaha F40 Outboard Service Manual, Page 340Get this manual
PTT gear pump
When disassembling the relief valve assembly r, make sure to note down the number of turns the lock screw is turned out from its original position
Turn in the lock screw the same number of turns as it was turned out when removed2Install new O-ring g, to the valve lock screw h3Install the relief valve assembly i, and then tighten the valve lock screw to the specified torque
Checking the gear pump
1Check the operation of the gear pump shaftsReplace the gear pump assembly if the shafts do not rotate smoothly
Checking the gear pump housing
1Check the gear pump housingReplace if corroded or cracked