A bent or obstructed fuel line between the tank and the Float cup can restrict the flow of fuel to the engine.
Floating Bowl type Carburetor
If the fuel tank is located above the carburetor, it is likely to be float type. (See photo below)
Dirt and gum are the carburetors ' greatest enemies, as they can contain several narrow passageways through which the fuel flows. Over time, rubber deposits can reduce these passageways. In addition, the tiny dust particles contained in the fuel will bypass a fuel filter and be directed to the carburetor. This can also obstruct everything. A patented carburetor cleaner can be used to clean everything.
How Float Bowl Works
The float and bowl function as a toilet cistern, keeping the fuel at a constant level so that it can be sucked into the carburetor. Float buoyancy causes it to rise. When the gas in the container reaches an established level, a needle at the top of the float is forced into a valve seat, closing the fuel inlet to the container. Without this system, the gas would simply feed by gravity to the carburetor, flooding. If the lawnmower does not run for more than a few minutes, the float Cup may not be filling or filling very slowly. If it is slowly filled, the mower is cut, but can often be restarted after it has been left for a while (because the container refills).
