If you own a Stihl MS 391 chainsaw, you might have run into some common issues that can be frustrating to deal with.
From starting troubles to performance hiccups, these Stihl MS 391 problems are more common than you think.
In this guide, we’ll walk you through the 10 most common problems and provide simple fixes to keep your chainsaw running smoothly.
Stihl MS 391 Problems (Short Overview)
The Stihl MS 391 is a powerful chainsaw, but like any tool, it can face some issues over time.
Problems like hard starting, overheating, or chain oiling troubles might pop up.
Don’t worry most of these can be fixed quickly with proper maintenance or small adjustments. Keep your chainsaw in top shape by addressing these issues early!
Read 10 Common Problems With Fixes In Easy Ways…
1. Hard Starting
The Stihl MS 391 chainsaw is a powerful tool, but hard starting can be a common problem for users.
This issue can make it frustrating to get the chainsaw running, especially when you need it most.
Causes
Hard starting in the Stihl MS 391 is often caused by a dirty air filter, old spark plug, stale fuel, or carburetor issues.
These problems can prevent the engine from getting the proper air-fuel mixture it needs to start.
Fixes
To fix this, start by cleaning or replacing the air filter, swapping out the spark plug, and using fresh, high-quality fuel.
If the problem persists, check and adjust the carburetor settings or consult a professional for repairs.
2. Overheating Issues
The Stihl MS 391 is a powerful chainsaw, but like any machine, it can sometimes face overheating problems, especially during extended use.
Overheating can reduce performance, cause engine damage, or even shorten the tool’s lifespan.
Causes of Overheating
- Blocked or clogged air filters restrict airflow.
- Insufficient engine oil or poor-quality oil.
- Prolonged use without proper breaks.
- Excessive dirt or debris around the cooling system.
Fixes for Overheating
- Clean or replace the air filters regularly.
- Use high-quality engine oil and check levels frequently.
- Allow the chainsaw to cool down during long tasks.
- Clear dirt and debris from the cooling fins and vents.
3. Chain Oiling
Proper chain oiling is crucial for the performance of your Stihl MS 391. If the chain isn’t getting enough oil, it can lead to overheating, increased wear, and poor cutting efficiency.
Causes
- Blocked oil ports or lines.
- Low or empty oil reservoir.
- Faulty oil pump.
Fixes
- Clean the oil ports and lines thoroughly to remove any debris.
- Refill the oil reservoir with the recommended chain oil.
- Inspect the oil pump and replace it if it’s malfunctioning.
4. Power Loss
Power loss is a common issue with the Stihl MS 391 and can significantly impact its performance.
This problem often shows up as reduced cutting efficiency or difficulty maintaining high RPMs during use.
Causes
Clogged air filters, dirty fuel lines, or a worn-out spark plug are common reasons for power loss.
Old fuel or carburetor issues can also lead to inconsistent engine performance.
Fixes
Start by cleaning or replacing the air filter and checking the fuel lines for blockages. Replace the spark plug if it’s damaged or worn.
If the issue persists, inspect and clean the carburetor or seek professional servicing to ensure optimal performance.
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5. Clogged Filter
A clogged air filter is a common issue with the Stihl MS 391 that can affect its performance.
Cause
The air filter often clogs due to prolonged use in dusty or dirty environments, where particles accumulate over time.
Fixes
Clean the air filter thoroughly using compressed air or warm, soapy water (if it’s washable).
If the filter is heavily damaged or worn out, replace it with a new one to ensure optimal performance.
Always inspect the filter regularly to prevent future clogs.
6. Spark Plug Problems
If your Stihl MS 391 isn’t starting or running smoothly, the spark plug might be the issue.
Cause
The most common causes include carbon buildup, faulty connections, or a completely worn-out plug.
Fixes
First, check the spark plug for damage or dirt. Clean it carefully or replace it with a new one if necessary.
Always ensure it’s properly connected and use the correct spark plug for your Stihl MS 391 for optimal performance.
7. Fuel Delivery
The Stihl MS 391 may experience fuel delivery problems that can impact its performance.
These issues often result in the saw struggling to start, running inconsistently, or stalling during use.
Causes
- Clogged fuel filter preventing proper fuel flow.
- Leaks in fuel lines or loose connections.
- A faulty carburetor or damaged fuel pump.
Fixes
- Clean or replace the fuel filter to restore fuel flow.
- Inspect and repair any damaged fuel lines or tighten connections.
- Rebuild or replace the carburetor or fuel pump if necessary.
8. Chain Tensioning
Proper chain tensioning is a common issue with the Stihl MS 391.
If the chain is too loose, it can slip off during use, while an overly tight chain can cause unnecessary wear on the bar and chain, reducing efficiency.
Cause
Chain tension problems often arise from regular usage, causing the chain to stretch or loosen over time.
Fixes
To fix this, regularly inspect the chain tension and adjust it using the tensioning screw. Ensure the chain has slight slack but still fits snugly against the guide bar.
Always refer to the user manual for proper tensioning techniques to prevent wear and ensure safe operation.
9. Vibration Trouble
If your Stihl MS 391 is causing excessive vibration, it can make the chainsaw uncomfortable and even unsafe to use.
Causes
- Worn or broken anti-vibration mounts
- Loose or damaged engine components
Fixes
- Inspect and replace damaged anti-vibration mounts
- Tighten or repair any loose engine parts
- Regularly maintain and check for wear to prevent further damage
10. Carburetor Issues
The carburetor is a common trouble spot in the Stihl MS 391, especially if the saw isn’t running smoothly or struggles to start.
Causes
Clogged fuel lines, dirty air filters, or stale fuel are the main reasons carburetors malfunction. Long periods of storage without proper cleaning can also lead to buildup inside the carburetor.
Fixes
Clean the carburetor thoroughly using a carburetor cleaner and check for any blockages in the fuel lines. Replace the air filter if it’s dirty and always use fresh, high-quality fuel. If the problem persists, a carburetor rebuild or replacement may be required.
FAQs
What is the price of the Stihl MS 391?
The price of the Stihl MS 391 typically ranges between $600 and $700, depending on the retailer and region.
How much does the Stihl MS 391 weigh?
The Stihl MS 391 weighs approximately 6.4 kg (14.1 lbs) without the cutting bar and chain.
How does the Stihl MS 391 compare to the MS 362?
The MS 391 is more affordable and suited for farm and ranch work, while the MS 362 is lighter, more fuel-efficient, and designed for professional forestry applications.
How big of a bar can I put on a Stihl MS 391?
The Stihl MS 391 can accommodate a guide bar length ranging from 16 inches to 25 inches.
What cc is a Stihl MS 391?
The Stihl MS 391 has a 64.1 cc engine.
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