I replaced the primer fuel bulb, fuel lines and fuel filter on a craftsman chain saw. Disassembly was straight forward and easy to get to the fuel bulb and fuel lines. The most difficult part of installation is getting the fuel lines threaded through the holes in the fuel tank and pulling enough line inside the tank to install the fuel filter and have the return line on the bottom of the tank. This is accomplished by trimming the end being inserted in the tank far enough so that it can be easily inserted in the holes at least an inch. Then use a needle nose pliers with very long handles to grab the lines inside the tank and pull while feeding the lines through the holes. Attach the fuel filter, slip it back in the tank and reassemble the chainsaw.