Parts

Parts and tools needed for the MS170 how-to video.

• Clutch Assembly - 1123 160 2050
• Chain Sprocket 3/8" Picco 6T - 1123 640 2003
• Clutch Shoe - 1129 162 0800
• 13/19mm Combination Plug/Bolt Spanner - 902 1361
• Locking Strip - 0000 893 5904
• N/G Torx Wrench/Plug Spanner (13mm & 19mm) - 410 250

Transcript

This video demonstrates how to change the clutch on a Stihl MS170.

Health & Safety Warning - Ensure the machine and workspace are safely prepared. Seek professional advice if unsure about any aspect of the task.

Changing the Clutch on a Stihl MS170 Chainsaw

We will change the clutch on a Stihl MS170 Chainsaw. Ensure the chain is free before starting.

Step 1: Loosen the Sprocket Cover

Use a 19mm Hex Socket Spanner to loosen the two nuts securing the sprocket cover on the side of the machine. Then, use a screwdriver to loosen the chain tensioning screw between the guide bar and the machine, which will slacken the chain.

Continue unscrewing the two sprocket cover nuts. This will allow you to remove the casing, freeing the chain and bar completely.

Step 2: Remove the Chain Sprocket

Using pliers, remove the circlip inside the chain sprocket. You can then take off the sprocket washer and chain sprocket. It’s a good idea to remove the sprocket bearing as well to prevent it from getting lost.

Step 3: Access the Machine's Interior

Use a flathead screwdriver to release the shroud by turning it clockwise. Remove the shroud. Take out the air filter by hand. Use a 19mm hex socket spanner to loosen the spark plug. Once loose, you can remove it by hand. Insert the piston stop through the spark plug entry to lock the crank, allowing you to unscrew the clutch.

Step 4: Remove and Check the Clutch

Using a 19mm spanner, turn the nut clockwise to loosen the clutch. Once loosened, spin it clockwise to remove. Inspect the clutch for wear, particularly on the springs. Replace if necessary.

Step 5: Reassemble the Machine

Spin the clutch onto the machine by turning it anti-clockwise. Tighten the clutch back onto the machine while keeping the piston stop in place. Place the sprocket bearing over the clutch, then fix the chain sprocket on top. Relocate the sprocket washer on top of the chain sprocket.

Use pliers to squeeze the circlip back into place. Hand screw the spark plug back in and tighten it with the 19mm spanner. Reinsert the air filter. Secure the shroud back in place by turning the plastic bolt anti-clockwise.

Step 6: Reattach the Chain

When placing the chain back onto the guide bar, ensure the cutting edge, highlighted in red, faces away from the machine's body on the top edge of the guide bar. The cutting edge should face the direction of the blade's rotation. Feed the chain around the bar and ensure it's seated correctly.

Check that the chain moves smoothly without snagging. Place the chain around the chain sprocket. Ensure the two screws are seated in the guide bar's opening. Replace the casing and hand screw the two nuts.

Use the screwdriver to tighten the chain tensioning screw between the guide bar and the machine. Once assembled, ensure the chain moves smoothly, is not too tight, and does not have excessive slack.

Conclusion:

This is how you change the clutch on the Stihl MS170. All parts and tools required for this task are listed in the description below.