This step-by-step line trimmer repair guide explains how to replace a line trimmer carburetor. The carburetor combines air and gas into a combustible mixture that ignites in the cylinder to power the engine. If the gas tank is full of fresh fuel but the engine won’t start, test the carburetor by removing the air filter and adding about a teaspoon of fuel into the carburetor. If the engine starts and then quickly dies when you pull the starter cord, the problem is probably the carburetor. Install a manufacturer-approved replacement part when replacing the carburetor.
Use this guide to replace the carburetor on common Craftsman, Weed Eater, MTD, Poulan, Toro, Troybilt, Cub Cadet and Husqvarna line trimmers.
Instead of replacing the carburetor, you can rebuild it, following the steps in How to Rebuild a Line Trimmer Carburetor.
Disconnect the spark plug wire
Disconnect the wire from the spark plug.
Disconnect the spark plug wire.
Drain the fuel tank
In a well-ventilated area, remove the fuel cap and the drain the tank into an approved storage container.
Disconnect the fuel lines
Take a digital photograph of configuration of the fuel lines attached to the carburetor, or make a diagram.
Pull the fuel lines off of the carburetor, using needle-nose pliers if necessary.
Disconnect the fuel lines from the carburetor.
Remove the air filter
Remove the cover from the air filter housing and then remove the air filter.
Remove the cover from the air filter.
Remove the air filter from the line trimmer.
Remove the carburetor
Use an Allen wrench to remove the 2 mounting screws that secure the carburetor to the engine.
Pull the air filter housing off of the carburetor. Remove the carburetor from the side of the engine. The throttle cable is still attached to the carburetor.
Take a digital photograph of how the throttle cable control cable connects to the carburetor or make a diagram. Disconnect the throttle cable and remove the existing carburetor.Tip: Check the gasket on the side of the engine and replace it if it's damaged.
Remove the carburetor mounting screws.
Remove the air filter housing.
Lift the carburetor off.
Disconnect the throttle control cable.
Install the new carburetor
Insert the throttle cable on the new carburetor the same way it was installed on the original carburetor.
Position the gasket on the nipples of the engine mount and hold the carburetor in place.
Install the filter housing and secure it with the 2 mounting screws. Using a torque wrench, tighten the screws to 25 in./lbs. of torque. If you don't have a torque wrench, tighten them reasonable tightly.
Reconnect the fuel lines
Referring to your digital photograph or diagram, connect the fuel lines to the new carburetor.
Reinstall the air filter and spark plug
Clean the air filter if necessary before installing it. Position the filter in place and close the cover on the filter housing.
Connect the spark plug wire on the spark plug.
Test the line trimmer
Fill the gas tank with the fuel mix and check that the line trimmer works.
The fuel line on a grass line trimmer deteriorates with time and eventually can split or crack. You can replace it yourself, following these instructions.
If the line trimmer engine won't start even though there's fuel in the tank, the carburetor could be the problem. Follow these instructions to do the job in under 30 minutes.
If the line trimmer won't start even though there's fuel in the tank, the carburetor could be the problem. Follow these instructions to replace the carburetor in under 30 minutes.
Use the advice and tips in these articles and videos to get the most out of your grass line trimmer.
These tips may help you get your hard-to-start gas line trimmer running.
Follow the steps in this video to replace a leaking fuel line in a line trimmer.