Service Manual

FUEL SYSTEM 3-9
Carburetor
Low Idle Speed Adjustment

Refer to Low Idle Speed Adjustment in the Periodic Maintenance
Chapter (2nd chapter).
High Idle Speed Adjustment

Refer to High Idle Speed Adjustment in the Periodic Maintenance
Chapter (2nd chapter).
High Altitude Operation
At high altitude, the standard carburetor air-fuel mixture will be
excessively rich. Performance will decrease, and fuel consumption will
increase. High altitude performance can be improved by installing a
smaller diameter main-jet in the carburetor and correct idle speed.
NOTE

The main jet high altitude kits are available if the equipment is to
be used in the high altitudes. The main jet numbers are stamped
on ends of the main jets.
High Altitude Main Jet
Main Jet No.
Altitude FH380V FH430V
0 1 000 m (0 3 000 ft) #78 #88
1 000 2 000 m (3 000 6 000 ft) #75 #85
2 000 m (6 000 ft) and higher #72 #82
Main Jet Replacement
•
Place the engine (equipment) on a level surface.
•
Close the fuel shut off valve in the equipment.
•
Remove the carburetor (see Carburetor Removal).
•
Unscrew the float chamber mounting bolt [A] and take off the float
chamber [B] and gasket.
•
Using a properly sized blade screw driver, carefully replace the main
jet [A] with a new one for altitude expected.
•
Tighten the main jet to the specification (see Carburetor Disassembly
Assembly Notes).
•
Install the float chamber and gasket.
•
Tighten float chamber mounting bolt.
Fuel system Cleanliness Inspection

Refer to Fuel System Cleanliness Inspection in the Periodic Mainte-
nance Chapter (2nd chapter).