How to Change the Carb on a Stihl TS-420 Cut-Off Saw

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Things You'll Need

  • Container

  • Socket set

  • Allen wrench

The TS-420 is a cut-off saw manufactured by Stihl. A cut-off saw, or abrasive saw, is a rugged saw with a large blade that is typically used to cut through hard materials like metal, ceramics or masonry. The TS-420 is a hand-held saw with a two-cycle engine that uses a carburetor for air-fuel combustion. The carburetor on the saw typically only needs maintenance from time to time. However, in some cases, the entire carburetor may have to be completely replaced if it becomes non-functional.


Step 1

Remove the spark plug wire from the TS-420 and then use the socket set to remove the spark plug.

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Step 2

Remove the gas cap, pour the gas inside the saw into a container and then replace the cap.

Step 3

Remove the starter cover bolts with a socket set and then pull the starter cover off.

Step 4

Remove the outer case screws with a screwdriver. Pull the case off and set it to the side.

Step 5

Pop the air filter cover off. Remove the air filter and then use the Allen wrench to remove the two bolts running through the top of the carburetor. Also remove the throttle linkage from the side of the carburetor.


Step 6

Remove the fuel lines from the ports of the carburetor and then use a screwdriver to remove the retaining screw holding the old carb in place. Set the new carburetor in its place, insert the retaining screw and fasten it with the screwdriver.

Step 7

Reconnect the fuel lines to the ports on the new carburetor and then slip the throttle linkage into place.


Step 8

Slide the two bolts back through the carburetor and tighten them with the Allen wrench. Also replace the air filter and air filter cover.

Step 9

Replace both the outer cover and the starter assembly.

Step 10

Fill the fuel tank back up with gas and replace the spark plug and spark plug wire.


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