Carburetor Accelerator Pumps
When a vehicle accelerates very quickly, large amounts of air and fuel are needed to supply the engine. Air and fuel flow at different rates, which can cause a lean mixture,causing the vehicle to misfire. Since air moves quicker than dense fuel, a pump is needed to supply more fuel to the mixture,in order to keep it enriched.
This pump which supplies extra fuel when the accelerator is pressed, is referred to as the accelerator pump. It is connected to the accelerator using a linkage. The accelerator pump is located on the side of the accelerator, where it supplies the shot of fuel. This shot of fuel is sprayed directly into the throat of the carburetor,in order to momentarily increase the fuel-to-air ratio. The fuel is injected using a small bent brass tube, which is pointed right down the neck of the carburetor.
The accelerator pump is only used if the accelerator is pushed far enough that the flow of fuel cannot keep up with the air. It is important that not too much fuel is let out by the accelerator pump, because it can wash oil off of the cylinder walls in the engine, which will wear out the pistons and rings, and cause a loss in fuel economy.
Accelerator pumps are also used to prime an engine, prior to a cold start. It is also important that accelerator pumps are set to only allow a certain amount of fuel to be released. Too much fuel and too little air,can cause flooding of the engine which won’t allow for combustion. To help prevent flooding of the engine, a mechanism called an unloader is used. The unloader holds open the choke, which allows for extra air to enter the engine when it is flooded, which will allow it to start easier.
Most accelerator pumps are also adjustable,in order to allow more or less volume of fuel, to be sprayed out. It can also have its duration of spray time changed,in order to allow a longer release of less fuel, or a quicker release of more fuel. Adjusting the volume and duration are ways to increase performance in modified engines. Over time, seals around the moving parts in the pump may fail, which can alter the volume of fuel being sprayed.
Who Makes This
- Item Name Coming Soon
Where to Buy