Mercury 7.4L Bravo Three, Operation & Maintenance Manual

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The fuel system components on your MerCruiser engine will with-
stand up to 10% alcohol content in the gasoline. We do not know
what percentage your boat’s fuel system will withstand. Contact your
boat manufacturer for specific recommendations on the boats fuel
system components (fuel tanks,fuel lines, and fittings). Be aware that
gasolines containing alcohol may cause increased:
•
Corrosion of metal parts.
•
Deterioration of rubber or plastic parts.
•
Fuel permeation through rubber fuel lines.
•
Starting and operating difficulties.
! WARNING
FIRE AND EXPLOSION HAZARD: Fuel leakage from any part of
fuel system can be a fire and explosion hazard which can cause
serious bodily injury or death. Careful periodic inspection of en-
tire fuel system is mandatory, particularly after storage. All fuel
components including fuel tanks, whether plastic metal or fi-
berglass, fuel lines, fittings, fuel filters and carburetors/fuel in-
jection components should be inspected for leakage, soften-
ing, hardening, swelling or corrosion. Any sign of leakage or
deterioration requires replacement before further engine oper-
ation.
Because of possible adverse effects of alcohol in gasoline, it is rec-
ommended that only alcohol-free gasoline be used where possible.
If only fuel containing alcohol is available, or if the presence of alco-
hol is unknown, increased inspection frequency for leaks and abnor-
malities is required.
IMPORTANT: When operating a MerCruiser engine on gasoline
containing alcohol, storage of gasoline in the fuel tank for long
periods should be avoided. Long periods of storage, common
to boats, create unique problems. In cars alcohol-blend fuels
normally are consumed before they can absorb enough mois-
ture to cause trouble, but boats often sit idle long enough for
phase separation to take place. In addition, internal corrosion
may take place during storage if alcohol has washed protective
oil films from internal components.