Is the carburetor idle mixture pre-set at overhaul?
The idle mixture is set to a nominal position when delivered from the shop to the distributor. This setting is approximately 1 1/2 turns from the full rich position. All carburetors should be set-up in accordance with the engine/airframe manufactures recommendations after the carburetor is installed and prior to the first flight. Proper idle characteristics are a combination of speed and mixture and can only be set on an engine running at normal operating temperatures. Mixture settings may require changing due to seasonal variations or changes in the density altitude at the airfield the aircraft is operating from.
