February 01, 2014

How to replace chainsaw fuel lines

The chainsaw fuel lines that carry fuel from the tank to the carburetor can clog, crimp or crack over time. Damaged fuel lines restrict fuel flow and prevent the engine from starting. If the chainsaw won’t start, clear clogs and check the fuel lines for cracks or crimps. Replace damaged or crimped fuel lines with the manufacturer-approved chainsaw part, following the instructions in this DIY chainsaw repair guide.

Follow the steps in this repair guide to replace fuel lines in common Craftsman, Husqvarna, McCulloch, MTD, Poulan and Troybilt chainsaws.

Quick links

Instructions

Tools required

Allen wrench

7/16-inch socket driver

Needle-nose pliers

Approved fuel container

Scissors

Work gloves

Wire coat hanger

paper towels or shop rags

Repair difficulty

Time required

15 minutes or less

Instructions

01.
Drain the fuel tank
Wear work gloves to protect your hands.
In a well-ventilated area, remove the fuel cap and empty the fuel tank into an approved storage container.
PHOTO: Open the fuel cap.
02.
Remove the cylinder shield
Using an Allen wrench, remove the screws that hold the cylinder shield to the engine. Lift off the shield.
PHOTO: Remove the cylinder shield.
03.
Disconnect the spark plug wire and remove the air filter
Disconnect the wire from the spark plug. Pull the cover off the air filter housing and remove the filter.
PHOTO: Disconnect the spark plug wire.
PHOTO: Remove the air filter cover.
PHOTO: Remove the air filter.
04.
Remove the fuel filter
Straighten a piece of coat hanger and bend a hook on the end. Feed it through the mouth of the tank and fish out the white cylindrical fuel filter. Cut the fuel line to remove the filter.
05.
Remove the carburetor
Using a 7/16-inch socket driver, remove the 2 mounting nuts that secure the carburetor to the engine.
Pull the air filter housing off the carburetor.
Pull the carburetor from the engine block, sliding it along the mounting studs. Be careful not to bend the throttle linkage or damage the gas lines.
Tip: For accurate reassembly, take digital photos of the throttle linkage on the carburetor and the gas line connections.
PHOTO: Remove the mounting nuts.
PHOTO: Remove the air filter housing.
PHOTO: Pull the carburetor off the mounting studs.
06.
Remove the old fuel lines
Pull the fuel lines off the carburetor and primer bulb, using needle-nose pliers.
Use needle-nose pliers to pull the fuel lines out of the gas tank.
Tip: With some chainsaw models, you’ll have to remove the screws from the primer bulb to detach the fuel lines.
PHOTO: Pull the fuel lines off of the carburetor.
PHOTO: Pull the fuel lines off of the primer bulb.
PHOTO: Pull the fuel lines out of the gas tank.
07.
Install the new fuel lines
Use a pair of scissors to cut the new fuel lines at an angle to thread them into the tank. Push the large line about 1 inch into the tank.
Push the small line far enough into the tank so that it can be grabbed through the mouth of the tank with needle-nose pliers.
Pull the small line out the mouth of the tank. Cut the end square and install the fuel filter. Pull the line back in so the filter rests on the bottom of the tank. Trim the fuel lines and connect them to the carburetor.
Tip: To ease threading, lubricate the fuel lines with a drop of oil.
PHOTO: Cut the end of the new fuel lines at an angle.
PHOTO: Fuel line cut at an angle.
08.
Install the fuel filter
Pull the small line out the mouth of the tank. Cut the end square and install the fuel filter. Pull the line back in so the filter rests on the bottom of the tank. Trim the fuel lines and connect them to the carburetor.
09.
Reinstall the carburetor
Slip the carburetor onto the mounting studs and push it into place. Position the air filter housing on the protruding studs.
Replace the mounting nuts and tighten them to seal the gasket between the engine and the carburetor.
Tip: Avoid crimping the fuel lines when re-installing the carburetor.
10.
Reinstall the air filter cover and connect the spark plug
Position the air filter in the housing and replace the cover. Reattach the spark plug wire.
11.
Reinstall the cylinder shield
Reinstall the cylinder shield on the chainsaw.
Refill the fuel tank.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.