Before diagnosing a carburetor, check the setting of the ignition timing, the serviceability of the spark plugs and the interelectrode gap in the candles. Check that the throttle cable and choke control mechanism are properly adjusted and that the air filter element is clean. If the engine is noisy, check the valve clearances and compression pressure in the engine cylinders.
If there are problems with the carburetor, determine that it may be more economical to replace the entire carburetor than individual parts of it.
Before disassembling the carburetor, purchase gaskets, jets and diaphragms. It should be noted that often in order to restore the normal operation of the carburetor, it is enough to disassemble it and clean the jets and air channels.