Specifications; Fuel Recommendations - Mercury MerCruiser MCM 454 Mag MPI Service Manual

MAINTENANCE
CA261

Fuel Recommendations

IMPORTANT: Use of improper gasoline can damage your engine seriously. Engine
damage resulting from use of improper gasoline is considered misuse of engine, and
damage caused thereby will not be covered under the limited warranty.
FUEL RATINGS
MerCruiser engines will operate satisfactorily when using a major brand of unleaded gaso-
line as follows:
USA and Canada - having a posted pump Octane Rating of 87 (R+M)/2 minimum. Premium
gasoline [92 (R+M)/2 Octane] is also acceptable. DO NOT use leaded gasoline.
Outside USA and Canada - having a posted pump Octane Rating of 90 RON minimum.
Premium gasoline (98 RON) is also acceptable. If unleaded gasoline is not available, use
a major brand of leaded gasoline.
CA291
USING REFORMULATED (OXYGENATED) GASOLINES (USA ONLY)
This type of gasoline is required in certain areas of the USA. The two types of "oxygenates"
used in these fuels is Alcohol (Ethanol) or Ether (MTBE or ETBE). If Ethanol is the "oxygen-
ate" that is used in the gasoline in your area, refer to "Gasolines Containing Alcohol."
These "Reformulated Gasolines" are acceptable for use in your MerCruiser engine.
CA618
GASOLINES CONTAINING ALCOHOL
If the gasoline in your area contains either "methanol" (methyl alcohol) or "ethanol" (ethyl
alcohol), you should be aware of certain adverse effects that can occur. These adverse
effects are more severe with "methanol." Increasing the percentage of alcohol in the fuel can
also worsen these adverse effects.
Some of these adverse effects are caused because the alcohol in the gasoline can absorb
moisture from the air, resulting in a separation of the water/alcohol from the gasoline in the
fuel tank.
The fuel system components on your MerCruiser engine will withstand 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.
Index Index
Page 1B-14
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Specifications

SERVICE MANUAL NUMBER 23
90-861326--1 MARCH 1999