Troy-Bilt is one of the leading brands of string trimmer, known for professional quality equipment. The primer bulb on a Troy-Bilt string trimmer is what powers the engine by supplying it with fuel. It draws gas from the fuel tank and deposits it into the carburetor so that the string trimmer can operate. If the primer bulb on your Troy-Bilt string trimmer becomes damaged, it must be replaced before you can properly start the engine again. Replacing the primer bulb on a Troy-Bilt string trimmer is a relatively simple process that only requires a few rudimentary tools.
Remove the cover of the Troy-Bilt string trimmer by unscrewing the screws to the cover.
Clean the area surrounding the primer bulb with a cloth or use an air compressor to blow the debris away.
Remove the screws that connect the primer bulb mounting plate.
Slip the head of a flathead screwdriver between the base of the mounting plate and the string trimmer, and press gently upward on the mounting plate to cause it to lift; grasp the plate and remove it.
Remove the old primer bulb from the mounting plate and pop the new primer bulb into the plate.
Replace the mounting plate back within the Troy-Bilt string trimmer and screw it back into place.
Replace the cover to the string trimmer and secure it by screwing it into place again.