TM 5-4310-276-14
Table 4-2. Troubleshooting (cont)
Malfunction
Test or Inspection
Corrective Action
Step 4. Inspect for water or dirt in carburetor.
Drain water from carburetor bowl.
a. Remove carburetor bowl drain screw and gasket.
b. Drain carburetor.
c. Reinstall drain screw and gasket.
Step 5. Inspect for carburetor out of adjustment.
Adjust carburetor.
a. Using figure 4-7 as a guide, adjust the carburetor.
b. With engine stopped, turn main adjustment needle and idle adjustment needle fully clockwise
to close.
c. Turn main adjustment needle three-quarters of a turn counterclockwise, and idle adjustment
needle one-half turn counterclockwise. Start engine and run until warm.
d. Apply load and observe engine exhaust. If exhaust is black, close main adjustment needle. If en-
gine misfires or seems low in power, open main adjustment needle. Adjust main adjustment needle until
engine delivers maximum power with minimum of exhaust smoke.
e. If engine application has a throttle speed adjustment, regulate idel mixture in a similar manner.
f. Regulate engine idle rpm by turning idle speed regulating screw clockwise or counterclockwise
enough to keep the engine running smoothly.
Step 1. Inspect for lean fuel mixture.
Adjust carburetor.
a. Using figure 4-7 as a guide, adjust the carburetor.
b. With engine stopped, turn main adjustment needle and idle adjustment needle fully clockwise
to close.
c. Turn main adjustment needle three-quarters of a turn counterclockwise, and idle adjustment
needle one-half turn counterclockwise. Start engine and run until warm.
d. Apply load and observe engine exhaust. If exhaust is black, close main adjustment. If engine
misfires or seems low in power, open main adjustment needle. Adjust main adjustment needle until en-
gine delivers maximum power with minimum of exhaust smoke.
e. If engine application has a throttle speed adjustment, regulate idle mixture in a similar manner.
f. Regulate engine idle rpm by turning idle speed regulating screw clockwise and counter-
clockwise enough to keep the engine running smoothly.
Step 2. Check if engine is running too slowly,
Unload engine and increase speed until normal operating temperature returns.
a. Unload engine by opening drain valve on underside of air tank.
b. Adjustment of speed control.
(1) Models 1A08-1 and 1A08-2 use figure 4-13 as a guide.
4-19