4 stroke small engine carburetors work using the same principles as a motorcycle carburetor. Typically, small engine carbs will be the simplest in design, falling into the mechanical slide category rather than the more complicated Constant Velocity design.
Due to the compact size of 2 stroke engines, they are often used on lawn equipment such as blowers, weed trimmers, chainsaws and more. These engines must work without the benefit of being gravity fed, as the nature of their use puts the engine in various positions, including upside down.
2 stroke small engine carburetors have the same job of mixing air and fuel at proper ratios as their 4 stroke carburetor counterparts. Their operation however, is slightly different.
Using a primer bulb and diaphragms, 2 stroke carburetors are able to create a pressurized, continuous loop of fuel from the fuel tank to the engine with any unused excess fuel fed back into the tank. There will not be a bowl to temporarily store fuel, rather, mechanically priming the bulb will pressurize the system, readying the fuel system to supply the engine.
