Like most other small engines, the Echo CS3000 chain saw uses a fuel bulb to prime the carburetor when starting the engine cold. When the fuel bulb develops cracks or holes, it is time to replace it. Replacing the fuel bulb on an Echo CS3000 chain saw is a bit different than most other engines. It is necessary to remove the fuel bulb from inside the air filter housing on the Echo CS3000. Replacement fuel bulbs are available through small engine repair shops and some home improvement stores.
Place the Echo CS3000 on a flat surface and pull the spark plug wire off the spark plug. Pull the choke out all the way just as you would when starting the chain saw cold. This closes the carburetor while you are removing the fuel bulb.
Remove the screw securing the air filter cover to the chain saw with a flat-head screwdriver. Take the air filter cover off, and pull out the air filter. The fuel bulb clips into the air filter housing. There are two fuel lines connecting to the body of the fuel bulb.
Hold the new fuel bulb upright, below the existing fuel bulb. Pull one of the fuel lines off the existing bulb with a pair of needle-nose pliers. Push the fuel line onto the same port of the new fuel bulb until the line is flush against the fuel bulb body.
Remove the remaining hose from the existing bulb with the needle-nose pliers, and push it over the remaining port on the new fuel bulb.
Find the clips on the existing bulb that secure it to the air filter housing. There is a clip on two sides, opposite from each other. Place the needle-nose pliers around the fuel bulb body, grasping the clips on each side. Push up slightly on the bulb body, and pull straight down to remove it from the air filter housing.
Press the new fuel bulb into the air filter housing until the clips lock the body in place. Insert the air filter into the housing, and replace the air filter cover. Plug the spark plug wire back over the spark plug.