A Tecumseh carburetor can be adjusted by allowing the engine to heat up, adjusting the speed of the engine to the highest maximum revolutions per minute and allowing it to run at a slow idling speed. These steps will ensure that the carburetor is able to function when the engine is idling, running normally and running at a high speed.
The engine should reach a normal operating temperature before any of the carburetors are adjusted. This will ensure that it is running at the optimal range for adjustment. The screw on the carburetor should be loosened very slowly while the engine is at its highest RPM. Once the RPM begins to slow down because the mixture that is entering the carburetor is too high, the screw can be slowly tightened.
The procedure can be repeated with the engine at a very low or idle speed. The difference in this procedure is that the idle screw will be loosened and tightened instead of the mixture screw.
The idle speed on the engine can be adjusted to make the engine run smoothly. This can usually be accomplished by simply listening to the sound the engine makes, but a tachometer can be used to set the engine to a specific idle speed.