Two adjustments are provided on the carburetor, the idle speed adjustment screw and the idle fuel adjustment needle.

Three factors control the conversion of the fuel air mixture into engine power. These factors are engine compression, ignition, and correct carburetor adjustment. Correct carburetor adjustment cannot be obtained unless engine compression and ignition meet specifications. Before proceeding with the carburetor adjustment, the following preliminary steps should be preformed to be sure that adjustments will be made correctly:

1. Set the idle speed adjustment screw so that the throttle plate is slightly open. Turn the idle adjustment needle in (clockwise) until it is seated lightly, then back it off approximately one turn.
2. Make ceratin that the fuel tank shut-off valve is in the open position.
3. Pull the choke knob, turn on the ignition, start the engine and push the choke knob in until the engine runs smoothly.
4. After the engine has reached normal operating temperature, be sure the choke knob is pushed all the way in, and proceed as follows:
   1. Turn the idle fuel adjustment needle in (clockwise) until the engine begins to roll, then back it off slowly, until the engine is running smoothly.
   2. With the hand throttle in the closed position, turn the idle speed adjustment screw until the engine idle speed is 600rpm.