Technical & Consumer Information; Technical Information; Serial Number Locations; Carburetor Modification For High Altitude Operation - Honda UMK431 Owner's Manual

TECHNICAL INFORMATION
This section contains important information about
serial number locations, operation at high
altitudes, oxygenated fuels and emissions control
systems.
Serial Number Locations
There are two serial numbers, one for the trimmer
and another for the engine. Record these
numbers in the space provided. You'll need to
have these numbers available when ordering
parts or making technical or warranty inquires
(page
52).
Frame serial number:
Engine serial number:
Q
/ -
FRAME SERIAL NUMBER
Carburetor Modifications 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 trimmer at altitudes above
5,000 feet (1,500 meters), have your servicing
dealer perform this carburetor modification.
Eve3 with carburetor modification, engine
horsepower will decrease about 3.5% for each
1,000-foot (300-meter) increase in altitude. The
effect of altitude on horsepower will be greater
than this if no carburetor modification is made.
pi5E-l
When the carburetor has been modified for high
altitude operation, the air-fuel mixture will be too
lean for low altitude use.
Operation at altitudes 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.
NUMBER
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46