Carburetor - TM-5-4320-234-120051

TM 5-4320-234-12

4-24. Carburetor (Fig. 4-10)

adjust the carburetor as follows:

a. Adjustment. If troubleshooting indicates that the

carburetor is responsible for faulty engine operation,

8. Main adjusting screw

Throttle cable

9. Carburetor float bowl

Throttle cable clamp

10. Flood relief drain cock

Idle speed adjustment screw

11. Choke control cable

Carburetor throttle lever

12. Choke cable clamp

Idle mixture adjustment needle

13. Carburetor choke lever

Carburetor inlet filter

Throttle rod

Figure 4-10. Carburetor, showing adjustment points.

(1) Start with engine and allow it to warm to

air admitted to the idling system which functions only at

operating temperature.

low speeds. Adjust as follows:

(a) With the engine at idle, turn the idle

(2) Adjust the main adjusting screw (8, fig. 4-

mixture adjustment screw clockwise to cut off air,

10). This adjustment determines the amount of fuel

making the fuel mixture richer, until the engine starts to

available for high-speed operation. Adjust as follows:

run roughly due to excessively rich mixture.

(a) Adjust the throttle control of the pump to open the

(b) Turn

the

adjustment

needle

carburetor throttle about one-fourth.

counterclockwise to obtain the smoothest idle operation

(b) Turn the main adjusting screw clockwise

possible.

to reduce the fuel to the engine until the engine begins

to miss due to a lean fuel mixture.

vacuum gage attached to the intake manifold and adjust

the

adjusting

screw

the needle for highest engine vacuum.

counterclockwise until the engine runs smoothly without

missing.

(4) Adjust the idle speed adjustment screw

(3, fig.

4-10).

Turn the screw clockwise or

(3) Adjust the idle mixture adjustment needle

counterclockwise as necessary to provide 400 to 600

(5, fig. 4-10). This adjustment controls the amount of

4-21