After The Break-In Period; Fuel Requirements; Fuel Ratings; Using Reformulated (Oxygenated) Gasoline (Usa Only) - Mercury MerCruiser Service Manual

General Information
• Do not operate below 1500 RPM for extended periods of time for the first 10 hours. Shift into gear as soon as possible after
starting and advance the throttle above 1500 RPM if conditions permit safe operation.
• Do not operate at one speed consistently for extended periods.
• Do not exceed 3/4 throttle during the first 10 hours. During the next 10 hours, occasional operation at full throttle is
permissible (five minutes at a time maximum).
• Avoid full throttle acceleration from idle speed.
• Do not operate at full throttle until the engine reaches normal operating temperature.
• Frequently check engine oil level. Add oil as needed. It is normal for oil consumption to be high during the break‑in period.
After the Break‑In Period
To help extend the life of your Mercury MerCruiser power package, the following recommendations should be considered:
• Ensure that the propeller allows the engine to operate at or near the top of the specified wide‑open throttle (WOT) RPM
range (refer to Section 1C ‑ Maintenance) when at full throttle with a normal boat load.
• Operation at 3/4 throttle setting or lower is recommended. Refrain from prolonged operation at WOT RPM.

Fuel Requirements

Running out of fuel can damage catalyst components. Do not allow the fuel tanks to become empty during operation.
IMPORTANT: Use of improper gasoline can damage your engine. Engine damage resulting from the use of improper
gasoline is considered misuse of the engine and will not be covered under the limited warranty.

Fuel Ratings

Mercury MerCruiser engines will operate satisfactorily with any major brand of unleaded gasoline that meets the following
specifications:
USA and Canada ‑ A posted pump octane rating of 87 (R+M)/2, minimum, for all models. Premium gasoline 91 (R+M)/2
octane is also acceptable for all models. Do not use leaded gasoline.
Outside USA and Canada ‑ A posted pump octane rating of 91 RON, minimum, for all models. Premium gasoline (95 RON) is
also acceptable for all models. Do not use leaded gasoline.

Using Reformulated (Oxygenated) Gasoline (USA Only)

Reformulated gasoline is required in certain areas of the USA and is acceptable for use in your Mercury Marine engine. The
only oxygenate currently in use in the USA is alcohol (ethanol, methanol, or butanol).

Gasoline Containing Alcohol

Bu16 Butanol Fuel Blends
Fuel blends of up to 16.1% butanol (Bu16) that meet the published Mercury Marine fuel rating requirements are an acceptable
substitute for unleaded gasoline. Contact your boat manufacturer for specific recommendations on your boat's fuel system
components (fuel tanks, fuel lines, and fittings).
Methanol and Ethanol Fuel Blends
IMPORTANT: The fuel system components on your Mercury Marine engine will withstand up to 10% alcohol (methanol or
ethanol) content in the gasoline. Your boat's fuel system may not be capable of withstanding the same percentage of alcohol.
Contact your boat manufacturer for specific recommendations on your boat's fuel system components (fuel tanks, fuel lines,
and fittings).
Be aware that gasoline containing methanol or ethanol may cause increased:
• Corrosion of metal parts
• Deterioration of rubber or plastic parts
• Fuel permeation through the rubber fuel lines
• Likelihood of phase separation (water and alcohol separating from the gasoline in the fuel tank)
Fuel leakage is a fire or explosion hazard, which can cause serious injury or death. Periodically inspect all fuel system
components for leaks, softening, hardening, swelling, or corrosion, particularly after storage. Any sign of leakage or
deterioration requires replacement before further engine operation.
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NOTICE
WARNING
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© 2016 Mercury Marine 90-8M0099748 eng DECEMBER 2015