The primer bulb on a Briggs & Stratton engine is what supplies the mower carburettor with fuel. If the primer bulb is damaged, deteriorated or faulty, it will not supply the lawnmower with the fuel that it needs to operate properly. Luckily, you can replace a Briggs & Stratton primer bulb with relative ease in order to restore your Briggs & Stratton mower to working order.
Locate the primer bulb, which is mounted below the air filter of your Briggs & Stratton engine. Remove the screw that secures the air filter so that you can get to the primer bulb with ease, and remove the plastic cap from the primer bulb.
Insert the tip of the flathead screwdriver into one of the notches located behind the retaining clip in which the Briggs & Stratton primer bulb sits.
Press the screwdriver inward and then turn its handle so that the blade of the screwdriver pushes outward in the notch toward the primer bulb, which will cause the retaining clip to pop forward.
Repeat the above process on the other notch to completely pull the retaining clip and bulb free from the engine.
Position the replacement Briggs & Stratton primer bulb within the housing, and place the new retaining clip (which came with purchase of your replacement bulb) around the bulb with the notch wings pointing outward.
Push the retaining clip onto the primer bulb with a ¾-inch socket set, and tap the clip around the notches with the screwdriver to ensure that it is secured around the primer bulb.
Replace the plastic cap back over the primer bulb, and screw the air filter into place again.
An ideal time to clean the air filter is when you are replacing the primer bulb, as you are removing it anyway to get to the bulb.
Beware of not securing the retaining clip completely around the bulb because the retaining clip holds the bulb within the assembly.