Oxygenated Fuels; Modification For High Altitude Operation - Honda TruGear HRC7113 Owner's Manual

ADDITIONAL INFORMATION
OXYGENATED FUELS
Some conventional gasolines are being blended with alcohol or an ether
compound. These gasolines are collectively referred to as oxygenated fuels. To
meet clean air standards, some areas of the USA and Canada use oxygenated
fuels to help reduce emissions. If you use an oxygenated fuel, be sure it is
unleaded and meets the minimum octane rating requirement. Before using an
oxygenated fuel, try to confirm the fuel's contents. Some states/provinces require
this information to be posted on the pump.
The following are the EPA approved percentages of oxygenates:
ETHANOL -(ethyl or grain alcohol) 10% by volume
You may use gasoline containing up to 10% ethanol by
volume. Gasoline containing ethanol may be marketed
under the name "Gasohol".
MTBE (Methyl Tertiary Butyl Ether) 15% by volume
You may use gasoline containing up to 15% MTBE by
volume.
METHANOL -(methyl or wood alcohol) 5% by volume
You may use gasoline containing up to 5% methanol by
volume, as long as it also contains cosolvents and
corrosion inhibitors to protect the fuel system. Gasoline
containing more than 5% methanol by volume may cause
starting and/or performance problems. It may also
damage metal, rubber, and plastic parts of your fuel
system.
If you notice any undesirable operating symptoms, try another service station, or
switch to another brand of gasoline. Fuel system damage or performance
problems resulting from the use of an oxygenated fuel containing more than the
percentages of oxygenates mentioned above are not covered under warranty.
MODIFICATION FOR HIGH ALTITUDE OPERATION
At high altitude, the standard carburetor air-fuel mixture will be too rich.
Performance will decrease, and fuel consumption will increase. A very rich
mixture will also foul the spark plug and cause hard starting.
High altitude performance can be improved by specific modifications to the
carburetor. If you always operate your mower at altitudes above 1,500 meters
(5,000 feet) have an authorized Honda commercial mower dealer perform this
carburetor modification.
Even with the modification, engine horsepower will decrease about 3.5% for each
300 meter (1000 foot) increase in altitude. The effect of altitude on horsepower
will be greater than this if no carburetor modification is made.
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