How to Adjust the Carburetor on a Stihl MS170 Chainsaw: Easy Steps



Adjust the Carburetor on a Stihl MS170 Chainsaw

To adjust the carburetor on a Stihl MS170 chainsaw: Turn ‘L’ & ‘H’ screws to default, start the saw, fine-tune ‘L’ for idle, then ‘H’ for full throttle.

If you own a Stihl MS170 chainsaw, you understand that proper maintenance is crucial for the longevity and performance of your equipment. One essential part of maintenance is the proper adjustment of the chainsaw’s carburetor. In this guide, we will walk you through the steps to adjust the carburetor on your Stihl MS170 for optimal performance.

Understanding the Carburetor of Your Stihl MS170 Chainsaw

The carburetor on the Stihl MS170 chainsaw is designed to mix the correct amount of air and fuel for combustion. When the carburetor is not properly adjusted, it can lead to a variety of issues, including poor engine performance, starting difficulties, and increased fuel consumption.

What You Will Need

  • Screwdriver
  • Carburetor adjustment tool (specific to Stihl chainsaws)
  • Clean work area
  • Protective gloves and eyewear

Step-by-Step Guide to Adjusting Your Carburetor

Follow these steps to adjust the carburetor on your Stihl MS170 chainsaw:

  1. Ensure Safety: Before making any adjustments, make sure the chainsaw is off and has cooled down. Wear protective gloves and eyewear.
  2. Locate the Carburetor Adjustment Screws: The Stihl MS170 chainsaw has three carburetor adjustment screws labeled as “L” (low speed), “H” (high speed), and “LA” (idle).
  3. Start with the “L” Screw: This screw controls the mixture at low speed. Use the adjustment tool to turn the “L” screw clockwise until it lightly seats, then back it out one turn counter-clockwise as a basic setting.
  4. Adjust the “H” Screw: This screw controls the fuel mixture at high speed. Similarly, turn the “H” screw clockwise until it lightly seats, and then back it out one turn counter-clockwise.
  5. Set the “LA” or Idle: Start the chainsaw and let it warm up. Adjust the “LA” screw until the chainsaw idles smoothly without the chain moving.

Troubleshooting After Adjustment

After adjusting your carburetor, it’s crucial to monitor your chainsaw’s performance for any irregularities:

IssuePossible CauseSolution
Chainsaw Dies or StallsIncorrect Idle AdjustmentFurther adjust the “LA” screw
Chainsaw Runs RoughImproper High/Low Speed MixtureRevisit adjustments for “H” and “L” screws
Poor Cutting PerformanceDull Chain or Mixture Too Lean/RichSharpen Chain, re-adjust carburetor

Important Tips

  • Always refer to the Stihl MS170 chainsaw manual for specific instructions and safety warnings.
  • Carburetor adjustment may void the warranty if not performed correctly. If you are unsure, seek professional help.
  • Regularly cleaning your air filter and spark plug can also improve performance.

Read more: What Gas Oil Ratio for Husqvarna Chainsaw


Adjusting the carburetor on your Stihl MS170 chainsaw can seem daunting, but with the right tools and a bit of patience, it’s something you can do on your own. Always prioritize safety and consult the user manual or a professional if you are unsure about any steps. A properly adjusted carburetor will ensure that your Stihl MS170 runs efficiently and lasts for years to come.

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