Mercury MERCRUISER, Service Manual, Page: 374 / 566

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)
!
WARNING
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.
IMPORTANT: If you use gasoline that contains or might contain methanol or ethanol, you must increase the frequency of
inspection for leaks and abnormalities.
IMPORTANT: When operating a Mercury Marine engine on gasoline containing methanol or ethanol, do not store the gasoline
in the fuel tank for long periods. Cars normally consume these blended fuels before they can absorb enough moisture to cause
trouble; boats often sit idle long enough for phase separation to take place. Internal corrosion may occur during storage if
alcohol has washed protective oil films from internal components.
Priming the Fuel System
IMPORTANT: Use a portable fuel tank with a primer bulb fuel line.
!
WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.
1. Disconnect the fuel line from the fuel tank to the fuel inlet fitting and plug the line, if attached to the engine.
2. Attach portable fuel tank to the fitting and secure tightly.
3. Squeeze the primer bulb until the bulb becomes firm.
4. Turn the ignition switch to the "RUN" position for 3 seconds and then turn OFF.
NOTE: Do not turn the key switch to the "START" position during the priming.
5. Repeat Step 3. and Step 4. three more times.
IMPORTANT: Before disconnecting the fuel line primer bulb, ensure that the bulb is soft and does not still have fuel in it to
prevent spilling fuel.
6. Disconnect the primer bulb fuel line from the fuel inlet fitting.
7. Remove the plug from the fuel tank fuel line.
8. Attach the fuel line from the fuel tank to the fuel inlet and tighten securely.
Alternate Priming Procedure for Fuel System
Fabricating a Pressure‑Relief Collection Tool
In order to take advantage of the alternative Priming Procedure a new pressure relief collection tool will need to be fabricated.
MPI ECT Fuel System
Page 5A-4 © 2016 Mercury Marine 90-8M0099748 eng DECEMBER 2015