5 Most Common STIHL MS 291 Problems and Their Solution

STIHL MS 291 Problems

STIHL MS-291 is a powerful high-tech mid-range chainsaw with a fuel-efficient engine, anti-vibration system, and pre-separation air filtration system. It can cut different types of trees and bushes around your property as a homeowner or as a professional.

Despite being famous among domestic users, it has some shortcomings which affect its performance. Some of the problems include being unable to get started, issues with the fuel system, electrical problems, and bar and chain issues.

Like other electrical and mechanical devices, STIHL MS-291 also requires proper maintenance and care so that it operates smoothly without having to deal with any problems.

stihl ms-291 problems

If you are facing any of these problems, I can help you in troubleshooting them in this article.

Overview of STIHL MS-291 Problems

Common Problems Quick solutions
The engine won’t start Refill the chainsaw with fresh gas, unclog the spark arrestor, spark plug, air filter, and carburetor, and unclog the blocked export ports.
Fuel system issues Replace the leaked fuel lines, clean the carburetor using a cleaning agent, and adjust it.
Electrical Problems Clean the dirty spark plug and replace the damaged muffler, piston, and spark plug.
Chain and bar Problems Adjust the chain tension using a tension screw, sharpen the dull chain, and straighten the bent bar. If severely damaged, replace it.
Other common problems Adjust the L screw, H screw, and Idle adjustment screws, clean the air filter or replace it, and replace the piston ring seal or head gasket of the cylinder.  

4 Common STIHL MS-291 Problems

1. Engine problems

Engine problems

I would say almost every machine operating on the engine show some degree of malfunction over time. Engines require much more care than you think and people simply neglect this fact. Your STIHL MS-291 engine may fail to start after multiple attempts or it stalls and sometimes gets overheated.


  1. Engine fails to start: Sometimes simply poor weather may cause your engine to not start. But if that’s not the case, it is most likely to caused by a faulty or dirty spark plug, contaminated gas, or clogged carburetor.
  2. Engine stalls: If your chainsaw starts and then stalls, this could be due to a clogged spark arrestor or air filter.
  3. Overheating issue: Your engine might get overheated due to insufficient oil or a blocked exhaust port.
Engine problems - cause & Solutions

Possible Solutions:

  • First, check your fuel tank for bad gas. If it is more than two months, the gas must have gone bad and contaminated. Drain the bad gas from the chainsaw and refill it with fresh gas.
  • Inspect the spark plug and then the carburetor for any damage. Unclog the spark plug if it is dirty with the help of a soft wire brush. To clean the carburetor, use Seafoam spray and gently spray it.
  • If your engine starts and stops running after a while, look for the clogged air filter and spark arrestor. If the air filter is clogged, simply replace it and if the spark arrestor is blocked, clean it thoroughly.
  • Check the amount of oil in the fuel tank, if it is insufficient, fill it. Then look for the blocked exhaust port, remove the dirt and carbon buildup, and try running the engine.

2. Fuel System issues

fuel system issues

The issues with your chainsaw fuel are one of the commonest problems faced by most STIHL users. Fuel-related problems which I came across while using STIHL MS-391 include fuel lines leakage, and carburetor problems.


  1. Fuel lines leakage: Whenever you see your chainsaw leaking fuel, the main culprit could be the fuel lines. Breakage in the fuel lines causes fuel to leak out of the chainsaw.
  2. Carburetor problems: The issues of carburetors are mostly linked to fuel or oil mix resulting from maladjustment.
fuel system issues - cause & Solutions

Possible Solutions:

  • Inspect and check for any leakage in fuel lines and if found, replace them immediately.
  • Check your carburetor’s condition and clean it using the cleaning solution. If your carburetor is maladjusted, adjust it accordingly.

3. Electrical problems

electrical problems

Most of the electrical problems arise in the ignition system, faulty spark plug, or power issues of the STIHL MS-291 chainsaw.


  1. Ignition system failure: When you find no spark in your chainsaw, the most likely reason is the ignition system failure which is caused by damaged ignition coils.
  2. Faulty spark plug: If the spark plug of your chainsaw is worn-out, dirty, or damaged, it can’t be able to ignite the engine’s fuel.
  3. Engine lacks power: Sometimes the engine of your STIHL MS-291 lacks the power to start and accelerate. This happens due to a damaged muffler, piston, or spark plug. 
electrical problems - cause & Solutions

Possible solutions:

  • Remove the top cover of the chainsaw and take out the damaged ignition coil. Replace this worn-out coil with the new one and put it back with the spark plug.
  • If your spark plug is found dirty, clean it thoroughly, and if it is worn out and damaged, replace it to get maximum output.
  • Look for the worn-out muffler, piston, or spark plug and replace the one not working.

4. Chain and bar problems

chain and bar problems

Issues with the chain and bar are among the first issues that you can face while using a STIHL MS-291. The most frequent issue that I faced myself was the chain keeps coming off. Other issues may include dull chains and bent bars.


  1. The chain keeps coming off: Your chain isn’t able to stay in put due to improper chain tension and worn-out drive sprocket or heel bar.
  2. Dull chain: Over time and with constant use or using the wrong sharpening angle makes your chain is dull and damaged.
  3. Bent bar: Your chainsaw’s bar gets bent when you don’t use it properly and due to pinching causing the chainsaw to not cut properly.
chain & bar problems - cause & Solutions

Possible solutions:

  • Adjust the wrongly set chain tension by adjusting the tension screws located at the sides of the guiding bars. When you tighten it, it will increase the tension and when you lose it, the tension is released and the chain becomes loose.
  • Look for the wear and tear of the drive sprocket and bar heels. If found worn-out, replace them as soon as possible.
  • If your chain is dull, sharpen it using a Dremel or a file.
  • Always use the right sharpening angle for cutting. And if by any chance, you don’t know it, read the owner’s manual for it.
  • Straighten the mildly bent bar using mullet or a hammer. But, if your bar is severely damaged, you might need to replace it.

Other Common Issues

Other than these 4 common issues, you can also face some other problems while using STIHL MS-291 such as:

1. Speed adjustment issue

Your STIHL MS-291 chainsaw contains screws that help you in adjusting the low to high-speed ensuring your chainsaw works smoothly for pruning and other cutting purposes. But sometimes these screws don’t work when you try to adjust to a set speed.

speed adjustment issue - cause & solutions


  • Before adjusting the screws, make sure the chain brake is engaged for your safety.
  • Locate the three screws in the carburetor, Idle speed screw, H screw, and L screw.
  • Turn the idle speed screw clockwise to increase the speed and counterclockwise to reduce it.
  • Turn the L screw clockwise to richen the fuel mixture and anticlockwise to lean it at low speed. While for high speed, turn the H screw clockwise to richen and anticlockwise to lean.
  • Once you have adjusted the screws, test it out to see what works best for you. 

2. Compression problem

When the compression is too low, you can experience power loss or the complete shutdown of the engine as it isn’t able to hold sufficient pressure in the cylinder to run smoothly.

compression problem - cause & solutions


The main cause of low compression is leakage of air in the piston ring seal or head gasket of the cylinder. Replace these components to prevent low compression.  

3. Clogged Air filter

The air filter is a component that easily gets clogged while you are using your STIHL MS-291 for some time. The air filter is responsible to maintain constant and clean air flow to keep the engine in the best condition. A clogged air filter results in the overheating of the engine and it stops working or stalls.

clogged air filter - cause & solutions


  • Check for debris and dirt accumulated on the air filter and if you find any of it clean it using soap and water. Rinse it for 20-30 minutes and then dry it and place it back.
  • If the air filter is damaged, take it out and replace it with a new one.

Maintenance and prevention tips

maintenance & prevention tips

To have the smooth operation of STIHL MS-291, you need to maintain and clean it regularly. Let me tell you the best way to keep your STIHL MS-291 in the best possible condition is by following the owner’s guidelines and instructions. Other than this, follow these simple maintenance tips:

  1. Make cleaning your regular task and not just clean the exterior components. Perform deep cleaning for the crucial components like the air filter, spark plug, and fuel filter.
  2. To keep your engine in the best condition it is important to have a fully functional, clean, and well-adjusted carburetor.
  3. Inspect the cooling fins and other areas that are involved in bringing clean air and look for any dirt or debris in the exhaust port.
  4. Make a habit to inspect the major components and quantity of fuel and other fluids before and after the use.
  5. After using, it is very important to store your chainsaw in a dry place and cover it so that no dust can enter.
  6. For safety, always wear safety gear, make sure the chain brake is engaged, and operate the chainsaw at a particular distance to avoid injuries and accidents. 

If you are wondering what is the recommended maintenance schedule given by STIHL. Then don’t hesitate to give a good read to the STIHL MS-291 owners instruction manual.


What are the causes of the STIHL MS 291 stalling during operation?

If your chainsaw starts and then stalls, this could be due to a clogged spark arrestor or air filter.

How can I fix a STIHL MS 291 that has a loose or broken chain?

Lift the nose of the guide bar and loosen the nuts on the guide bar, tighten the tensioner screw, and secure back the nuts to fix a loose chain.

What are the most common causes of oil leaks on a STIHL MS 291 chainsaw?

Poor ventilation and overfilled oil tank are the most common causes that lead to oil leakage.

What size bar can you put on a STIHL MS-291?

The 16-inch sized bar is recommended to put on a STIHL MS-291.

Final Words

STIHL MS-291 is a perfect choice for those who are looking for a powerful mid-range chainsaw for different kinds of cutting. But this great machine also faces some problems if you are not taking good care of it.

Related article: Stihl MS 291 Vs Husqvarna 455: Which One Reigns Supreme?

As already discussed, you can face starting problems, electrical issues, chain problems, and issues with the fuel system. And the good part is all these problems are one step away from being solved and that is some good DIY techniques and effective maintenance tips.

If you want your STIHL MS-291 to stay in perfect working condition, the key is proper maintenance and adopting preventive measures.

Clean and inspect your machine regularly to avoid any of these problems.

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