Before attempting to correct faulty engine performance through carburetor adjustment, check over "Locating Troubles," Section 1. In addition, be sure air cleaner element is clean, and check carburetor and manifold connections to be sure they are tight and not leaking air.

1. Low speed mixture needle

2. Throttle stop screw

3. Throttle lever

4. Choke lever

5. Accelerating pump

6. Inlet fitting

7. Bowl drain plug

8. Bendix part no. and change letter

Figure 3-70. Bendix Carburetor Adjustments

The low speed needle, Figure 3-70, should be turned clockwise, or in, to make leaner mixture, and counterclockwise, or out, to make mixture richer. Needle is held to whatever position set by a spring.

Carburetor may be adjusted as follows:

Turn low speed mixture needle all the way in (clockwise) until seated (do not overtighten). Back out the low speed needle 1-1/2 turns. (With needle in this position, the engine will start but the mixture will be too rich.)

Adjust throttle lever stop screw (2, Figure 3-70) to make engine idle at desired speed with throttle fully closed. Turning screw clockwise makes engine idle faster. Never set idle adjustment to slowest possible speed. An extremely slow idle causes bearing wear, oil consumption and slow speed accelerating difficulties.

Make final readjustment on low speed needle after engine is warm. First in, and then out, to see if engine picks up speed or runs more smoothly. Starting and all around carburetion will be better with low speed mixture adjustment set slightly rich rather than lean. If necessary, make further adjustment on idle stop screw to obtain desired idling engine speed. Recommended idle speed is 700to 900 rpm.

During high speed operation, fuel is metered by a fixed jet which has no adjustment.

Operating conditions, such as high altitudes or hard service, may require other than the standard main fuel fixed jet. The following main fuel jet orifice sizes are available: No. 90, No. 95, No. 100, No. 105, No. 110, No. 115, No. 120 and No. 125.

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