At what throttle settings are float-type carburetors with economizers typically adjusted?

Float-type carburetors with economizers are typically adjusted below approximately 60-70% of rated power because this is generally where the mixture can become too rich due to increased fuel flow relative to air flow at higher throttle settings. The economizer is a feature designed to enhance fuel economy and performance by adjusting the fuel-to-air ratio under varying load conditions, particularly during medium throttle settings. By making adjustments at this range, the carburetor can ensure optimal performance and efficient fuel usage during typical operating conditions, which do not often require full throttle.

Adjusting at full throttle or high speeds may not provide accurate measurements for everyday operation, where the engine is frequently operating on partial throttle. Similarly, adjusting only at idle does not account for the transition to higher throttle settings that the economizer is designed to address. Therefore, focusing on the moderate throttle settings allows for better performance tuning of the carburetor and helps maintain efficient fuel management across various engine loads.