Major STIHL MS171 Problems and Their Solutions

STIHL MS171 is a prominent member of the lightweight generation of STIHL chainsaws which is well-known for its reduced emission technology and fuel-efficient engine. Despite being a professional chainsaw, STIHL MS171 has some shortcomings.

Some of the common problems faced by most users include starting issues, chain problems, and engine and fuel issues. but there is nothing to worry about as I got solutions to all your problems related to STIHL MS171.

stihl ms171 problems

This article will help you in solving all these problems with some quick and easy fixes.

Overview of Common Problems of STIHL MS171 and Their Solutions

Stihl Stihl MS 171 Problem Quick Solutions
Faulty spark plug Replace the spark plug with a new one
Residual fuel Use the right and high-quality fuel
Faulty ignition coil Check for circuit breaks and replace the coil.
Incorrect fuel-to-oil ratio Use recommended 50:1
Clogged fuel filter Repair it or replace it.
Old/contaminated fuel Replace it with fresh fuel.
The chainsaw keeps bogging down Clean the air filter, carburetor, and spark arrestor.
Dull chain Sharpen the chain using the file or electric sharpener.
Improper chain tension Set the chain tension using tension screws.
Damaged chain bar Straighten the chain bar with a hammer.

Major STIHL MS171 Problems With Their Fixes

1. Starting Problems

Starting problems

The most common problem faced while using MS171 is it won’t start at all or it takes some time to start. Both of these issues are annoying and caused either due to faulty or clogged spark plug, residual fuel, or faulty ignition coil.

i) Faulty spark plug

Over time spark plug wears out, its electrodes get damaged or it wholly gets burnt. Due to this, the spark plug is unable to provide the necessary ignition resulting in your chainsaw not starting.

Quick fix:

I sincerely recommend you replace your spark plug once a year whether it is damaged or not to keep your MS171 in good condition.

iii) Residual fuel

The leftover fuel in the fuel tank after use can combine with the air and water vapors to form a sticky tarnish that clogs the carburetor and causes the engine to not start.

Quick fix:

The best possible troubleshooting tip to avoid this problem is to use the right and high-quality fuel.

iv) Faulty ignition coil

Sometimes the spark plug is in good condition but it still won’t start the engine. In such a case, the issue is in the ignition coil. A faulty ignition coil makes it impossible for the spark plug to get the necessary voltage to function.

Quick fix:

With the help of an ohmmeter, check for circuit breaks and replace the ignition coil with a new one.

2. Fuel Issues

Fuel issues

Another common problem that occurs in STIHL MS171 is issues of fuel which are caused due to incorrect fuel-to-oil ratio, clogged fuel filter, and old/contaminated fuel.

i) Incorrect fuel-to-oil ratio

Sometimes if you use an incorrect fuel-to-oil ratio, it causes several issues including scaring the pistons and cylinders of the engine or fouling the spark plug.

Quick fix:

Just like me, always use the recommended ratio of fuel and oil and for most of the chainsaw, the correct fuel-to-oil ratio is 50:1. [50:1 Vs 25:1– Which Oil Mix Is Perfect For You?]

ii) Clogged fuel filter

The function of the fuel filter is to provide a smooth flow of fuel to the engine and any damage or clogging of the fuel filter will result in blockage of fuel from the tank to the fuel lines depriving the engine of adequate fuel supply.

Quick fix

I will advise you to always clean the fuel filter whenever you refuel your STIHL MS171 and if you find it clogged or damaged repair it on a priority basis and replace it when necessary.

iii) Old/contaminated fuel

The old or contaminated fuel can cause permanent damage to your engine as well as the carburetor.

Quick fix:

If you find your fuel is stale or old, immediately replace it with fresh fuel. I regularly check the amount as well as the quality of the fuel, this has eliminated the possibility of my fuel getting stale.

3. The chainsaw keeps bogging down

chainsaw keeps bogging down

I personally faced this issue, after some time my MS171 keeps on getting stuck while cutting. This happens when:

  • The air filter, spark arrester, or carburetor are clogged with dirt and debris.
  • One other cause is the slipping down of the adjustment screws of the carburetor.

Quick fix:

Follow these tips to fix this issue:

  • First comes first, clean your carburetor with some carburetor cleaning solution.
  • Remove the air filter and clean it with the help of compressed air or wash it with soap.
  • Remove the spark arrestor behind the muffler and clean it using a wire brush and then place it back.
  • If the air filter and spark arrestor are beyond repair, replace them with new ones.
  • Adjust the high-speed screws by cranking up the throttle attached to it.

4. Performance Issues

Performance issues

Sometimes MS171 doesn’t give you high-end and clean cutting resulting in poor performance of the chainsaw. This can occur due to a dull chain, improper chain tension, and a damaged chain bar.

i) Dull chain

When you improperly or roughly use the chainsaw, it can cause the teeth of the chainsaw to become uneven resulting in wear and tear to the chain.

Quick fix:

The best way that I use myself is by removing the chain and sharpening it manually. You can either use a file or an electric sharpener to do this job.

Read: How to Sharpen a Chainsaw with a Dremel

ii) Improper chain tension

Correct chain tension is crucial to make proper contact with the wood to cut. And if it is incorrect, it simply won’t cut through anything.

Quick fix:

You can easily set the chain tension correctly using the tension screw or follow these steps:

  • Lose the bar nuts on the guide bar.
  • Now adjust the tensioning screws.
  • Next, tighten the guide bar side nuts while lifting its nose.

iii) Damaged chain bar

The function of the chain bar is to help the chain slides across it and if it is damaged, it may not be able to cut. Even a slightly bent or damage to the chain bar can greatly affect your chainsaw performance.

Quick fix:

A mildly bent chain bar can be straightened using a hammer while you need to replace the severely bent chain bar with a new one.

Preventive Maintenance of STIHL MS171

Preventive maintenance of STIHL MS171

Like any other machine, your chainsaw also requires regular maintenance to ensure high-end cutting performance and longer shelf-life. Here are some important maintenance tips for you to follow to get the best results out of STIHL MS171:

  1. Regularly clean air filter, fuel filter, cooling fins, and spark arrestors.
  2. A spark plug is an important component of the engine therefore it requires regular inspection to prevent your chainsaw from stalling.
  3. Chain brakes should be checked regularly to make sure it is working perfectly.
  4. Check and adjust the chain tension of your chainsaw. A loose or tighten chain can affect the performance of your equipment.
  5. Clean the guide bar and check for a bent chain bar.
  6. Use high-quality and fresh fuel for the smooth running of the engine and also mix it in the correct ratio according to the manufacturer’s guidelines.
  7. Make sure to store your chainsaw in a dry and cool place and keep it away from humidity. Cover it well so that no dust or debris can accumulate over it.

When to Seek Professional Help?

Always remember you and I can be pro in maintaining and troubleshooting our chainsaws but we are neither trained nor we are professional. If you slightly think, you won’t be able to solve the issue, it is better to take your machine to a professional for the best services.

Another thing is, STIHL provides maintenance services through authorized dealerships where people are trained specifically in maintaining and repairing STIHL chainsaws. You can find information related to these service centers on the official website of STIHL.

One more thing to remember is the warranty coverage. Every chainsaw has a warranty of some time and if you think your MS171 is still under the warranty period you can replace it.

Final Words

STIHL MS171 is a great chainsaw but like any other machine, it also faces some problems and issues which are manageable. Some of the common problems include starting problems, performance problems, chain problems, and bogging issues.

And the best part is all of these issues can be fixed by: using the correct fuel-to-oil ratio, using fresh and high-quality fuel, sharpening the chain, cleaning the air filter, fuel filter, spark arrestor, and carburetor, and adjusting the chain tension.

If you want your chainsaw to work for several years, make sure to follow preventive maintenance, seek the help of a professional when required, and follow the care guidelines provided by the manufacturer.

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