Replacing Chainsaw Primer Bulb And Fuel Line: Diy Guide

The primer bulb on a chainsaw is responsible for drawing fuel from the tank into the carburetor, which is necessary to start the engine. Over time, the primer bulb can become damaged due to constant contact with fuel, leading to hardening and cracking. This can cause issues with starting the chainsaw. Replacing the primer bulb and fuel line is a relatively straightforward process that can be done by the chainsaw owner. The steps include draining the fuel, removing the relevant components for access, disconnecting and replacing the primer bulb and fuel lines, and reassembling the chainsaw.

How to Replace Primer Bulb and Fuel Line on Chainsaw

Drain the fuel from the chainsaw

To drain the fuel from the chainsaw, you will need to remove the top cover and the starter assembly. This will involve unscrewing the screws that secure these components in place and setting them aside. With the top cover off, disconnect the spark plug. Then, remove the air filter cover and set it aside as well. Next, take out the air filter from its housing and put it to the side. Now you can access and remove the carburetor, which is where the fuel is stored.

The carburetor is connected to the fuel lines and the primer bulb, which is what you will be replacing. To remove the carburetor, you will need to first remove the choke lever. Then, disconnect the fuel line that runs from the primer bulb to the carburetor. You can then pull the throttle trigger to access and disconnect the throttle linkage. With the throttle linkage disconnected, you can now remove the carburetor by sliding it off the mounting bolts and away from the engine.

At this point, you will be able to drain the fuel from the carburetor. Make sure to do this carefully and have a suitable container ready to catch the fuel. Once the fuel is drained, you can move on to replacing the primer bulb and fuel line.

It is important to note that you should always drain fuel from a chainsaw in a well-ventilated area and take the necessary precautions to avoid any accidental spills or fires.

Remove the top cover and starter assembly

To remove the top cover and starter assembly, first, unscrew the three T25 screws on the top cover. Then, remove the top cover and set it aside. Now, disconnect the spark plug. Remove the four T25 screws securing the starter assembly to the side of the chainsaw. Once that's done, remove the starter assembly and set it aside.

At this point, you can move on to removing the air filter cover and air filter from the housing, and then set them aside. Unscrew the single T25 screw securing the air filter housing to the carburetor. Remove the two 5/16" nuts securing the air filter housing to the carburetor.

Disconnect the fuel line from the primer bulb

Disconnecting the fuel line from the primer bulb is a crucial step in replacing the primer bulb and fuel line on a chainsaw. Here is a detailed guide on how to perform this task:

Firstly, locate the primer bulb on your chainsaw. It is usually found in the middle of the return line, which brings unused fuel back into the tank. Once you have identified the primer bulb, gather the necessary tools for the job. You will need a flat-head screwdriver or a spudger, as well as long-nose pliers.

Now, let's begin the process of disconnecting the fuel line:

• Using your flat-head screwdriver or spudger, gently pry or press the tabs on the inside of the primer bulb assembly. This will release the primer bulb from its housing. Be careful not to apply too much force, as you don't want to damage the surrounding components.
• With the primer bulb released, you can now access the fuel lines connected to it. Use your long-nose pliers to carefully grasp each fuel line and gently pull them away from the primer bulb. Take note of which line is the fuel intake port and which is the return port, as you will need to know this for reassembly.
• Once the fuel lines are disconnected from the primer bulb, set the primer bulb aside. You may now proceed to replace the fuel lines or perform any other necessary maintenance tasks.

Remember to work carefully and deliberately, ensuring that you don't misplace any parts or forget the orientation of the fuel lines. It is always a good idea to take photos or make notes during the disassembly process to aid in reassembly.

By following these steps, you will have successfully disconnected the fuel line from the primer bulb on your chainsaw, allowing you to proceed with the rest of the replacement or maintenance procedure.

Remove the carburetor

To remove the carburettor from your chainsaw, you will first need to drain the fuel from the tank. Then, remove the top cover and the starter assembly. Next, take out the air filter and the air filter base.

Now, you can begin to remove the carburettor itself. Start by removing the choke lever. Then, remove the fuel line that runs from the primer bulb to the carburettor. Pull the throttle trigger to access the throttle linkage, and remove this from the carburettor. At this point, you can pull the carburettor away from the saw.

It is important to be careful not to bend the throttle linkage or damage the gas lines during this process.

Reinstall the fuel lines and other parts

Now that you've replaced the primer bulb, it's time to reassemble the fuel lines and put the other parts back into position.

First, cut the fuel lines to the desired length, making sure they're not too long or too short. Then, attach one end of the new fuel line to the incoming fuel port on the carburetor. Next, move the fuel line through the primer bulb housing and hold the primer bulb up to the fuel line. Once everything is lined up, you can attach the cut end of the primer fuel line to the intake port of the primer bulb.

Now, slide the carburetor back onto the mounting bolts and pull out any slack in the fuel lines. Push the primer bulb back into its housing. Cut the fuel return line and push it into the gas tank, ensuring it reaches the bottom.

Next, cut the fuel filter line and attach the new fuel filter. Push this line into the gas tank, ensuring it also reaches the bottom. Reconnect the throttle linkage to the carburetor linkage, and pull and hold the throttle trigger to expose the attachment point for the trigger portion of the throttle linkage. Connect the throttle linkage to the trigger.

Now, reconnect the choke lever. Slide the air filter housing back onto the carburetor mounting bolts and secure it with the appropriate screws and nuts. Install the new air filter and cover.

Finally, connect the kill switch wire and install the starter assembly. Secure the assembly with the required number of screws. Pull the starter rope slowly until the flywheel engages the starter assembly. Reconnect the spark plug and install the top cover, securing it with screws.

And that's it! You've successfully replaced the primer bulb and fuel line on your chainsaw and reassembled all the parts. Your chainsaw should now be ready to use again.

Frequently asked questions