The primer bulb on your lawn mower's Tecumseh engine delivers fuel to your carburetor when you press the bulb with your fingers. A bulb that has cracks or is otherwise defective requires replacement. Replacing a Tecumseh primer bulb is slightly different than with other types of small engines. The retainer ring is a solid ring rather than a C-clip. Replacement bulbs are available at Tecumseh authorized dealers.
Locate the retainer ring that secures the primer bulb to the Tecumseh engine carburetor. The retainer has six tabs that secure the ring into the orifice.
Stick a small flat-head screwdriver in the small pace between the retainer ring tabs and the side of the orifice. Gently pry the ring up with the screwdriver. Pull the screwdriver out and insert into another space in the tabs. Continue prying the retainer ring until it is free from the orifice.
Pull the primer bulb and retainer ring away from the engine. Insert the new primer bulb into the orifice. The lip of the bulb sites on the inside edge of the orifice.
Slide the new retainer ring over the bulb. Place the open end of a 5/8-inch deep well socket over the top of the retainer ring. Gently tap the socket with a hammer to seat the retainer ring inside the orifice.