5.4
Section 5
Fuel System and Governor
Troubleshooting Fuel System
Carburetor Adjustment
NOTE: Carburetor adjustments should be made only
after the engine has warmed up.
The carburetor is designed to deliver the correct fuel-
to-air mixture to the engine under all operating
conditions. The main fuel jet is calibrated at the factory
and is not adjustable*. The idle fuel adjustment needle
is also set at the factory and normally does not need
adjustment. If the engine is hard starting or does not
operate properly, however, it may be necessary to
adjust or service the carburetor.
*NOTE: Engines operating at altitudes above
approximately 1830 m (6000 ft.) may require
a special high altitude main jet. Refer to
High Altitude Operation later in this section.
Figure 5-3. Fixed Main Jet Carburetor.
Condition
Possible Cause/Probable Remedy
1a. Low idle fuel mixture/speed improperly adjusted. Adjust the low idle
speed screw, then adjust the low idle fuel needle.
b. Improper choke adjustment.
1. Engine starts hard, runs roughly or
stalls at idle speed.
2. Engine runs rich. (Indicated by
black, sooty exhaust smoke,
misfiring, loss of speed and power,
governor hunting, or excessive
throttle opening).
2a. Choke partially closed during operation. Check the choke lever/
linkage to ensure choke is operating properly.
b. Low idle fuel mixture is improperly adjusted. Adjust low idle fuel
needle.
c. Float level is set too high. With fuel bowl removed and carburetor
inverted, the exposed surface of float must be parallel with the
bowl gasket surface of the carburetor body.
d. Dirt under fuel inlet needle. Remove needle; clean needle and
seat and blow with compressed air.
e. Bowl vent or air bleeds plugged. Remove fuel bowl, low idle fuel
adjusting needle, and welch plugs. Clean vent, ports, and air
bleeds. Blow out all passages with compressed air.
f. Fuel bowl gasket leaks. Remove fuel bowl and replace gasket.
g. Leaky, cracked, or damaged float. Submerge float to check for
leaks.
3. Engine runs lean. (Indicated by
misfiring, loss of speed and power,
governor hunting, or excessive
throttle opening).
3a. Low idle fuel mixture is improperly adjusted. Adjust low idle fuel
needle.
b. Float level is set too low. With fuel bowl removed and carburetor
inverted, the exposed surface of float must be parallel with the
bowl gasket surface of the carburetor body.
c. Idle holes plugged; dirt in fuel delivery channels. Remove fuel
bowl, low idle fuel adjusting needle, and welch plugs. Clean main
fuel jet and all passages; blow out with compressed air.
4. Fuel leaks from carburetor.
4a. Float level set too high. See Remedy 2c.
b. Dirt under fuel inlet needle. See Remedy 2d.
c. Bowl vent plugged. Remove fuel bowl and clean bowl vent. Blow
out with compressed air.
d. Float is cracked or damaged. Replace float.
e. Bowl retaining screw gasket damaged. Replace gasket.
f. Bowl retaining screw loose. Torque screw to specifications.
Idle Fuel
Mixture Needle
Idle Speed (RPM)
Adjustment Screw
Summary of Contents for Kohler SV470
Page 1: ...Workshop manual Kohler Courage Tractor Engines English ...
Page 3: ......
Page 17: ...1 14 Section 1 Safety and General Information ...
Page 43: ...5 16 Section 5 Fuel System and Governor ...
Page 93: ...9 14 Section 9 Inspection and Reconditioning ...
Page 116: ...2004W27 114 03 04 26 ...