A McCulloch 3216 chain saw has a 32 cc, gasoline-powered engine with a 16-inch bar and chain. The primer bulb on small engines adds fuel to the carburetor, to assist with starting the engine. Primer bulbs wear and become brittle, and may crack or develop holes, making them ineffective. At that point, you've got to replace the primer bulb to get your chain saw up and running again.
Pull the black, rubber spark plug boot off the spark plug on the rear of the chain saw engine to prevent the tool from starting accidentally.
Examine the primer bulb on the left side of the engine, above the pull rope. Place shop towels underneath the primer bulb to soak up fuel in case a drop or two runs from the fuel line.
Insert a T8 Torx screwdriver into the four screws on the recoil housing surrounding the pull rope. Turn the screws counterclockwise to loosen and remove the screws. Place a flathead screwdriver underneath the recoil housing and pry it off the chain saw.
Grasp the primer bulb at the top right of the housing and pull it outward gently. Pull the fuel line from the rear; use needle-nose pliers if necessary.
Insert the fuel line onto the rear of a new primer bulb. Align primer bulb the mounting tabs with the mounting ring's slots on the chain saw. Slide the new primer bulb inward and press it inward firmly.
Replace the starter housing, insert the screws and tighten them clockwise. Press the spark plug boot firmly onto the spark plug.