Cruising Rpm; Fuel Requirements; Fuel Ratings; Using Reformulated (Oxygenated) Gasoline (Usa Only) - Mercury MerCruiser 8.2 Horizon ECT Operation & Maintenance Manual

Section 3 - Specifications

Cruising RPM

Material and design advancements allow modern inboard engines to operate at higher engine speeds than their predecessors.
Increased RPM significantly increases the horsepower of these new engines and is a critical part performance and efficiency.
The materials and design of the new engines allow these higher speeds without durability penalty. Overpropping the boat to
reduce its cruising RPM to previous levels increases the engine's susceptibility to engine damage from detonation and
preignition. The recommended cruising RPM ranges are:
Model
Horizon 8.2
8.2 H.O.

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.
IMPORTANT: If you use gasoline that contains or might contain methanol or ethanol, you must increase the frequency of
inspection for leaks and abnormalities.
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Cruising RPM for Peak Efficiency
NOTICE
WARNING
!
RPM range
3200–3600
3400–3800
90-8M0113925 DECEMBER 2015
eng