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Stihl Ms 391 Problems

Edited ByS. Parves Hours Updated onOctober 8, 2022 Categories Guides

Do you intend to purchase a Stihl ms 391chainsaw for personal or professional use? Undoubtedly, ms 391 will be a great choice for its numerous safety and powerful features.

But are these all you’ll get from Stihl MS 391? What about Stihl ms 391 problems that you may encounter after owning?

Keep reading on to learn the most common STIHL MS 391 Chainsaw problems that are faced by its customers and the most effective solutions.

This way, you’ll be able to avoid and fix those troubles to boost its performance and your productivity.

Jump To Right Section
  • STIHL MS 391 Chainsaw- Overview
  • Loose Chain
  • The Chain Is Too Long
  • The Muffler Needs Replacement
  • Suddenly Lost Power
  • Chainsaw Won't Start
  • Have A Vapor Lock
  • Stihl Ms 391 Recall 
  • A Few Potential Stihl MS 391 Chainsaw Problems
  • Is The Stihl 391 Worth It?
  • Final Words

STIHL MS 391 Chainsaw- Overview

The STIHL MS 391 chainsaw is specially designed for the extreme job in mind.

STIHL MS 391 Chainsaw- Overview

It has plenty of impressive features, including increased power, superior fuel economy, and low emissions, making it popular among weekend warriors and professional loggers.

It also features an advanced anti-vibration system, an air filtration system, and tool-less oiling, making it perfect for convenient use.

Unlike the typical chainsaw, this STIHL chainsaw can get through any tough job without bogging down.

With a combination of dependable performance and ease of operation, this chainsaw has remained an excellent choice among hobbyists for a long time.

An incredible benefit of using this chainsaw is that it doesn’t bog down in thicker wood or while cutting at an angle, thanks to its two different gears. 

Combine with lower and higher speed functions, this chainsaw can conquer any wood-cutting job efficiently. It also features a side-access chain tensioner to increase efficiency.

Stihl Ms 391 Chainsaws Problems

Stihl Ms 391 Chainsaws Problems

Due to its ability to deliver high power output, this STIHL MS 391 chainsaw is handy for both professionals and homeowners.

But the flywheel of this chainsaw can break and crack, which can cause serious injury to the operator and anyone nearby. The other problems include:

Loose Chain

Some users notice that the chain of this Stihl ms 391 gets loose.

While a too loose chain won’t let you cut the wood efficiently in full throttle mode, an under tightened chain will come off frequently and sag during operation.

To fix the too loose or under-tightened chain, inspect the guide bar of the saw and replace it if worn out.

The Chain Is Too Long

Stihl Ms 391 Chain Is Too Long

Are you facing trouble while cutting with STIHL MS 391? You are not alone, many hobbyists face s the same Stihl Ms 391 problem.

It can happen due to using too long a chain. If so, shorten the chain with a 72DL chain to ensure a snug fit. Remember, you should sharpen the chain every four hours and rotate it after filling up.

The Muffler Needs Replacement

After owning the Stihl MS 391 chainsaw, you’ll need to replace the muffler as it can get a leak and start producing foul-smelling fumes.

These fumes are toxic to inhale and, if dispersed, can worsen the situation.In this case, a new muffler can funnel out the exhaust fumes completely.

Suddenly Lost Power

Stihl Ms 391 Suddenly Lost Power

Does your Stihl MS 391 chainsaw ever stop suddenly?

If not, then you are lucky enough. Some woodworkers experience that their Stihl chainsaw stops suddenly after running for around 10 minutes. 

They state that the machine was in excellent condition but lost power and finally cut out. They had also tried to re-start the machine but didn’t notice any pulling on the starter handle.

even if they didn’t get any tension in the starter cable.

The problem can occur due to using old fuel, which causes air leakage in several places. Stale fuel runs lean and faster; hence, it gets hotter with less lube.

Apart from that, the Stihl chainsaw can lose power sufficiently to protect you from potential injury.

The Stihl chainsaw is designed with a chain-stopping system to reduce the risk of kickback. Its quick-stop brake activates automatically when the user pushes the chainsaw forward.

Apart from automatic, some Stihl chainsaws also feature manual chain break to block kickback pressure.

Looking carefully, you’ll find the latter Q and G in the chainsaw. These indicate the place where the chain break has.

Chainsaw Won’t Start

Stihl Ms 391 Chainsaw Won’t Start

Three different parts of the Stihl chainsaw can be relied upon to prevent it from getting the start. They are the spark, fuel, and compression.

To check the spark, simply ground the plug back into the cylinder head. Then pull your Stihl ms 391 chainsaw over and verify if it is the fault of the spark. If the spark fails, put a spare in any way.

To test the fuel, squirt a little fuel into the carb and check it. If the fuel fires, check the fuel line and make sure it is attached securely and doesn’t have any leakage.

The next part to check is compression. In this case, you’ll need a proper tester. Start with the starter cord.

If you find the cord is spooled out and the saw lower to the ground, it means the chainsaw causes internal injury. 

Take off the muffler and check the side of the cylinder. If you notice it is messed up badly, fix it immediately.

Have A Vapor Lock

A pinched fuel line is among the serious Stihl ms 391 problems that can lead to worse situations.

If the fuel line pitches somehow, the engine of this chainsaw will die. At the same time, it will introduce a vapor lock. 

And this lock can cause fuel geysers, which can end up causing serious burn injuries.

Though it’s not happened frequently, at least seven people recall this vapor lock problem, according to the Stihl website.

Stihl Ms 391 Recall 

Stihl Ms 391 Recall 

Apart from the vapor lock system, many users recall the Stihl ms 391 due to chain breaks. That’s why Stihl urges the user to take proper action for their safety before hilding the ms 391 chainsaw.

In this case, you can contact them through their website and they’ll be glad to assist you. 

Even some enthusiasts mark this Stihl ms 391 as a recalled chainsaw as its flywheel tends to corrode and wear out. However, you can avoid this damage by replacing the flywheel from the authority free of charge. 

So, if you already own a Stihl ms 391, contact your dealer right away to find out if your chainsaw is affected.

A Few Potential Stihl MS 391 Chainsaw Problems

Oil Leak

If the pump cover gasket wears out or gets damaged, the Stihl chainsaw can cause oil leakage. Its oil pump drive gear can also creak and cause leaks. 

Cylinder Fins

Your Stihl ms 391 can leak fuel and its crankcase can mix with air if the cylinder fins get damaged. As a result, you can experience low engine power and poor starting.

Piston Ring

Stihl Ms 391 Piston Ring

The damaged piston ring can force you to experience poor engine compression, even for a week.

Carburetor

If an excessive amount of dirt and debris is present in the air filter, the carburetor of your Stihl chainsaw can get clogged.

In this case, cleaning the air filter system will let you restore the performance efficiently. 

Despite this, it’s recommended to check and clean the air filter system regularly to prevent the curborator from getting clogged.

Is The Stihl 391 Worth It?

All the brands have their misses and hits, including Stihl. Though there are some Stihl ms 391 problems, this chainsaw is still a top choice for ranches and farms.

Msa 391 is a highly powerful and functional chainsaw, and most experts and enthusiasts appreciate it. 

More importantly, it is built with the most recent engine technology to ensure greater fuel efficiency while emitting fewer emissions than comparable models and brands.Lastly, it won’t be wise to think that you’ll experience the same problem that we listed above.

Final Words

STIHL MS 391 is an incredible saw that offers great power output without burning too much fuel.

This chainsaw is also easy to handle as comes in a very lightweight design. so you can use this robust chainsaw for your all-day job including firewood cutting, felling, and storm cleanup tasks.

But expectedly, you will notice some Stihl 391 problems like the all chainsaws available out there.

So instead of being fret, it’ll be wise to check, learn, and be aware of them so you can avoid or solve them in the right way within a short time. And make your homework based on this guide.

S. Parves

Chief Editor @The Saw House (or, in plain English, I'm the guy responsible for ensuring that every blog post we publish is helpful for our readers.

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