Yamaha F40H Owner's Manual page 49

ECM01635
Make sure that the idle hole is high

enough to prevent water from entering
the engine even if the boat is stationary
with the maximum load.
Incorrect engine height or obstructions

to the smooth flow of water (such as the
design or condition of the boat, or ac-
cessories, such as transom ladders or
depth finder transducers) can create
airborne water spray while the boat is
cruising. If the outboard motor is oper-
ated continuously in the presence of
airborne water spray, enough water
could enter the engine through the air
intake opening in the top cowling to
cause severe engine damage. Remove
the cause of the airborne water spray.
ZMU01762
Installation
42