Walbro Carburetor Parts | Walbro Carburetor Application Chart
The primer bulb is one of the most common parts to fail on diaphragm carburetors for small engine applications. Often the primer bulb hardens and cracks causing a loss of vacuum under the bulb. If you suspect that your primer bulb is faulty but there are no visible signs of cracking, try inspecting the fuel line inside and outside the tank. Another possibility could be a plugged fuel filter inside the tank.
Replacing a Walbro primer bulb is a simple process that requires removing the metal housing holding the primer bulb in place. This is usually accomplished with a small Phillips screw driver. After removing the old primer bulb, make sure the area under the housing is clean before installing the new bulb. Any dirt or material from the old primer bulb remaining in the housing could also cause the new bulb to not seal properly around the edge.
There are several different types and sizes of Walbro primer bulbs and it is essential that the correct bulb is used for replacement. There are also external mounted Walbro primer bulbs that attach to the equipment and have separate fuel lines to the carburetor and fuel tank. Failure of these external type primer bulbs can be a failure of the fuel lines behind the bulb assembly and not the bulb itself.