Section 4 - Specifications
Page 44
90-864197072 NOVEMBER 2007
Cruising RPM
Material and design advancements allow modern inboard engines 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.
Over‑propping the boat to reduce its cruising RPM to previous levels increases the engine's
susceptibility to engine damage from detonation and pre‑ignition. The recommended
cruising RPM ranges are:
Cruising RPM for peak efficiency
Model
RPM range
5.7 MPI
3400–3800
Horizon 5.7
6.2 MPI
3600–4000
Horizon 6.2
Fuel Requirements
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
damage caused thereby will not be covered under the limited warranty.
Fuel Ratings
Mercury MerCruiser engines will operate satisfactorily when using a major brand of
unleaded gasoline meeting the following specifications:
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.
Using Reformulated (Oxygenated) Gasolines (USA Only)
This type of gasoline is required in certain areas of the USA. The 2 types of oxygenates
used in these fuels is Alcohol (Ethanol) or Ether (MTBE or ETBE). If Ethanol is the
oxygenate that is used in the gasoline in your area, refer to Gasolines Containing Alcohol.
These Reformulated Gasolines are acceptable for use in your Mercury MerCruiser engine.
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 Mercury 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 boat's
fuel system components (fuel tanks, fuel lines, and fittings). Be aware that gasolines
containing alcohol may increase:
Summary of Contents for 6.2 MPI
Page 8: ...Page iv 90 864197072 NOVEMBER 2007 ...
Page 20: ...Section 1 Warranty Notes Page 12 90 864197072 NOVEMBER 2007 ...
Page 36: ...Section 2 Getting to Know Your Power Package Notes Page 28 90 864197072 NOVEMBER 2007 ...
Page 56: ...Section 4 Specifications Notes Page 48 90 864197072 NOVEMBER 2007 ...
Page 100: ...Section 6 Storage Notes Page 92 90 864197072 NOVEMBER 2007 ...
Page 106: ...Section 7 Troubleshooting Notes Page 98 90 864197072 NOVEMBER 2007 ...