International Harvester produced the Farmall 140 tractor from 1958 to 1973. Equipped with a 12 volt electrical system, the 140 retains the offset operator platform that characterized its predecessor, the Farmall 130. A total of 66,290 of this model rolled off the assembly line at IH’s Louisville, Kentucky, factory. Its four-cylinder engine runs on an 11 gallon tank of gasoline and generates as much as 23 horsepower. Synthesizing the air and fuel for proper engine function is the carburetor.
The float chamber holds a quantity of ready-to-burn fuel, which is continuously disbursed and replenished. This resupply is by means of a flotation object that triggers an open valve upon sinking to a certain depth. The Farmall 140 refills around 15 inches of a 32-inch bowl.
A choke serves to inject fresh fuel into the engine. After many hours at rest, a tractor’s immediately available fuel may condense into an unusable consistency. The choke pushes fresh fuel into the carburetor for engine combustion by opening a valve. The optimal opening is about halfway on the 140.
The accelerator pump is activated under open-throttle conditions. When the throttle is opened, air can overwhelm the delicate air-to-fuel ratio, causing disruption in operation. The accelerator pump generates more fresh fuel to counteract the excess air that fills the carburetor. On the 140, the throttle shaft is 4.88 inches and triggers the accelerator pump when fully open.
The Farmall 140 has a 4.125-inch air cleaner cap that filters particulates from the air traveling to the carburetor. This cap fits over the air cleaner intake tube and consists of finely meshed metal strips. This piece serves to catch the larger pieces of material as opposed to the near molecular sizes trapped by the air filter.