When should carburetor adjustments be made?

The timing of carburetor adjustments is crucial for optimal engine performance. Making these adjustments with the air cleaner on the engine mimics the normal operating conditions of the engine. The air cleaner plays a vital role in regulating the airflow into the carburetor; therefore, having it in place ensures that the adjustments account for any restrictions or changes in airflow that may occur during actual engine operation.

When adjustments are made with the air cleaner removed, it can lead to an overestimation of the fuel-air mixture needed, as the engine will not be operating under its standard conditions. Conversely, making adjustments only during assembly may not reflect the engine's behavior in its running state, which can lead to improper tuning. The correct approach ensures the carburetor is optimally adjusted to work with the specific air intake configuration of the engine during normal operation.