Mercury HP 500 EFI Bravo XR/XZ/III, User Manual, Page: 77 / 148

73 500 EFI Bravo
ca425hp
MAINTENANCE
Replacement Service Parts
WARNING
Electrical, ignition and fuel system components on MerCruis-
er gasoline power packages are designed and manufactured
to comply with US Coast Guard rules and regulations to mini-
mize risks of fire or explosion.
Use of replacement electrical, ignition or fuel system compo-
nents, which do not comply to these rules and regulations,
could result in a fire or explosion hazard and should be
avoided.
When servicing the electrical, ignition and fuel systems, it is
extremely important that all components are properly in-
stalled and tightened. If not, any electrical or ignition compo-
nent would permit sparks to ignite fuel vapors from fuel sys-
tem leaks, if they existed.
Marine engines are expected to operate at or near full-throttle for
most of their life. They are also expected to operate in fresh and
saltwater environments. These conditions require numerous special
parts. Care should be exercised when replacing marine engine parts
as specifications are quite different from those of the standard
automotive engine.
For example, one of the most important, and probably the least
suspected special replacement part, is the cylinder head gasket.
Since saltwater is highly corrosive, the steel-type automotive head
gasket cannot be used. A marine engine head gasket uses special
materials to resist corrosive action.
Since marine engines must be capable of running at or near
maximum rpm much of the time, special valve springs, valve lifters,
pistons, bearings, camshafts and other heavy-duty moving parts are
required for long life and peak performance.
These are but a few of the many special modifications that are
required in MerCruiser marine engines to provide long life and
dependable performance.