Always take the time to inspect the air inlet before deciding to repair or replace the carburetor. Look into the inlet first for any signs of dirt. If dirt is present, then the air filter may not be working properly. The filter is easily replaced so figure out the reason for the dirt. If the problem has been present for any length of time, dirt ingestion may have caused internal damage. If the engine had a lot of dirt ingestion, it may need to be replaced. If there is no dirt problem, check for fuel leakage in the inlet next.
If fuel is escaping through the air inlet, the source may be a leaking inlet needle valve. Remove the bowl and check for fuel inside the float. In plastic floats, fuel will be visible. Metal floats can be shaken for sounds of fuel sloshing inside. The float should actually float when fuel is within the bowl of the carburetor. If it sinks, it will constantly feed fuel to the carburetor without shutting the fuel flow off. The solution is to replace the float.
Next check the inlet needle and seat. If the seat is missing, the carburetor will receive too much fuel and leak. Make sure the pointed end of the needle valve seats down against the inlet valve seat. This part is a small round plastic or rubber piece approximately the shape of a pencil eraser, though somewhat smaller. The material's composition is fuel resistant. If the seat is not properly installed around the tip of the needle, fuel will leak around this tip. If the material swells for any reason, it will block the entry of fuel into the float chamber. If you ever have to remove the seat, install a new one to ensure the proper fit. Remember that the pointed end of the needle valve clip should be positioned pointing towards the intake of the carburetor to prevent any leaking, binding or flooding. This little piece is a different color from the carburetors metal so you can check its position. Peer down the hole the inlet valve goes into and it can be seen at the bottom.
Expensive repairs of carburetors and replacement of engines can be avoided through these do-it-yourself inspections. A Tecumseh Inlet Needle Kit or Assembly can be purchased online or at any lawn and garden or hardware stores if your inspections reveal the need for maintenance of your carburetor.