How Does the Primer Bulb on a Walbro Carburetor Work?
Primer Bulb Walbro carburetors are a common type of carburetor found on two-stroke engines such as those that power weed eaters, chainsaws, leaf blowers and other lawn care tools. Despite their small and lightweight appearance, they’re complex machines that rely a great deal on the smooth supply of fuel from the fuel reservoir to function. Two-stroke engines do not have a separate oil reservoir, but instead, combine oil with gasoline. The fuel passing through the carburetor can be particularly viscous and difficult to move. It’s nearly impossible to start a two-stroke engine without making use of the primer bulb. Design The Walbro carburetor primer bulb is a small plastic bulb which sits on the outermost casing of the carburetor. Beneath this casing is a small chamber which directly connects to the primer bulb known as the top cover. A plastic fuel line leading out of the top cover is the fuel return pipe, which connects to the device’s fuel reservoir. Running back from the top cover i