Hypro HY160, Operation Manual

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20
Models: 2541-0047 thru 2541-0051
Carburetor 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 mix-
ture will also foul the spark plug and cause hard
starting. Operation at an altitude that differs from
that at which this engine was certified, for extended
periods of time, may increase emissions.
High altitude performance can be improved by spe-
cific modifications to the carburetor. If you always
operate your engine at altitudes above 5,000 feet
(1,500 meters), have your servicing dealer perform
this carburetor modification. This engine, when
operated at high altitude with the carburetor modifi-
cations for high altitude use, will meet each emis-
sion standard throughout its useful life.
Even with carburetor modification, engine horse-
power will decrease about 3.5% for each 1,000-foot
(300-meter) increase in altitude. The effect of alti-
tude on horsepower will be greater than this if no
carburetor modification is made.
When the carburetor has been modified for high
altitude operation, the air-fuel mixture will be
too lean for low altitude use. Operation at alti-
tudes below 5,000 feet (1,500 meters) with a
modified carburetor may cause the engine to
overheat and result in serious engine damage.
For use at low altitudes, have your servicing
dealer return the carburetor to original factory
specifications.
Oxygenated Fuels
Some conventional gasolines are being blended
with alcohol or an ether compound. These gaso-
lines are collectively referred to as oxygenated
fuels. To meet clean air standards, some areas use
oxygenated fuels to help reduce emissions.
If you use an oxygenated fuel, be sure it is unlead-
ed and meets the minimum octane rating require-
ment.
Before using an oxygenated fuel, try to confirm the
fuel’s contents. Some areas 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 con-
taining more than the percentages of oxygenates
mentioned above are not covered under warranty.
Technical & Consumer Information