Why Your Stihl Chainsaw Won’t Start + Troubleshooting Tips

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Stihl chainsaws are lavish and yet are valuable investments to any woodworker, so it’s definitely upsetting to find out that your high-priced tool suddenly stopped working. 

I’ve faced this issue myself, so I understand the frustration. In this guide, I want to share some of the common problems I’ve encountered with Stihl chainsaws and the troubleshooting procedures that have helped me get them back up and running.

Common Issues with Stihl Chainsaws

Stihl chainsaw and fuel can

Here are the Stihl chainsaw parts and their recurring problems, according to most users:

As shown, most of these issues are common and not limited to Stihl chainsaw units only. Below you will find the top issues involving these components as well as a few troubleshooting tips.

What Causes a Stihl Chainsaw Not to Start + How to Troubleshoot

Issue #1: Bad Spark Plug

Faulty wiring connections are a common culprit for a tripped ignition module, leading to a lack of spark on the plug. When a bad spark plug ignites the fuel, it can flood the chainsaw, preventing the engine from starting. Another common issue is the choke being left open, which can cause the engine to flood as well.

chainsaw defective spark plug

How to Fix

In my experience, chainsaws require the right balance of fuel to generate that essential spark. Too much fuel can spell trouble, causing the saw to flood and potentially affecting the ignition module. To address an engine flood in a Stihl chainsaw, here’s a straightforward fix:

Grab a socket set to remove the spark plugs from the cylinder head, and then use some trusty microfiber cloths to thoroughly dry them out.

While you’re at it, take a moment to inspect the electrode gap. If you notice that the tip of your plugs has turned black, that’s a clear sign it’s time to replace your spark plug wire. 

You have a couple of options here. You can either give the spark plugs a good sanding to clean them up, or you can take the damaged plug to a nearby home improvement store to find a suitable replacement.

This method is also used to repair a chainsaw that starts but then stops when gas is applied.

Issue #2: Worn Out Rewind Spring

Another cause of trouble in starting the engine is a worn-out rewind spring. The rewind spring recoils the string with the pulley intact when you pull the starter rope, but broken rewind springs won’t do as much job to the combustion chamber. 

chainsaw rewind spring

Most would even try to haul the rope multiple times and still end up with no combustion. 

How to Fix

Here’s a hands-on tip I’ve picked up over the years: if you’re having trouble with your chainsaw’s starter, it’s essential to check for tension. When there’s excessive tension on the spring, it can prevent the rope from smoothly pulling or causing issues with the starting recoil.

To tackle this, you’ll want to disassemble the rewind spring and ensure the rope doesn’t get caught up, creating unnecessary tension when you pull it.

Now, if you find yourself in the situation where you need to replace a worn-out rewind spring, remember to give that chainsaw engine some time to cool off. This step is crucial to avoid any accidental burns when dealing with those broken wires. Safety first, as they say.

Issue #3: Clogged and Dirty Carburetor

When you don’t drain the fuel on a chainsaw after use, the evaporated gas leaves a thick and sticky residue that is often the culprit of a dirty carburetor. 

Stihl chainsaw carburetor

The fuel blocks the carburetor and intercepts the engine from starting, and if this continues, you’ll have to replace the whole carburetor.

How to Fix

Carburetor problems are common, even to the most efficient Stihl chainsaws. To fix a clogged carburetor, use a carb cleaner to break up the residue. 

If a carburetor cleaner doesn’t unclog the fuel, you can try rebuilding it with a carburetor repair kit. But if there’s still an unruly clog, the only option left is to replace the entire carburetor. 

Issue #4: Bad or Old Fuel

Fuel intake has a lot to do with machine maintenance and what may be causing your Stihl chainsaw to stall. Fuel intake problems, like dirty or clogged fuel, can damage fuel flow, prompt an engine to stop working, and restrict airflow in the cylinder. 

adding fuel to Stihl chainsaw

How to Fix

Inspect the fuel tank, and clean and refill the gas tank with a fresh gas mix. Check for the other parts of the gas tank, such as the rims, as gas will snip at these areas when left for a long time. 

Use mild detergent to clean the clogged fuel tanks, and pair it with a small brush for the stubborn debris or gas stains on the cylinder.

Issue #5: Loose Fuel Lines

The chainsaw engine will most likely get idle with fuel leaks, often brought about by loose fuel hoses. Calibrating your fuel lines for a tighter grip and hold is more inexpensive than calling a mechanic every time it dies out. 

How to Fix

I’ve been in situations where dealing with loose fuel hoses on a chainsaw was a necessity. Let me tell you, having the right tools can make all the difference. In my experience, investing in a quality pair of short and long-nose pliers is the key to making this task more manageable for anyone.

One thing to keep in mind while you’re at it is to exercise caution. Those fuel lines can be a bit delicate, and you don’t want to accidentally tear them while you’re repairing them. So, take your time and handle them with care.

Issue #6: Clogged Air Filter

Like humans, chainsaw engines need air to breathe and function. Air filters on Stihl chainsaw decontaminate and prevent clogging onto your power machine, improving performance. 

Stihl chainsaw clogged air filter

However, clogged or dirty air filters will limit air into the chamber, causing the saw to stall and sputter. Replace the air filter as advised to preserve the longevity of the machine.  

How to Fix

When it comes to cleaning a dirty filter, I’ve found that taking a thorough approach can make a world of difference. Here’s what I’ve learned over the years:

Start by allowing the engine to cool down. Once it’s safe to handle, give the cylinder fins and air intake slits a good cleaning. Use a brush to tackle the visible dirty areas, being careful not to miss any spots.

Now, when it comes to those fleece filters, a gentle tap can help ensure those small pores become visible again. Once you’ve done that, carefully place the cover back in its position.

But here’s a pro tip for those stubborn dirt situations: consider using a product like Stihl Varioclean or soapy water for those air filters. It can work wonders in getting rid of that tough, persistent grime.

Issue #7: Compression Problems

Proper compression is essential for efficient collaboration amongst the spark, cylinder, and fuel systems. 

One of the complex yet most common reasons why a Stihl chainsaw fails to start is the compression issues brought about by air leak or clogged fuel from evaporated gas. Unregulated compression can cause the piston to seize the cylinder, decreasing the engine life. 

Stihl chainsaw compression demonstration

Check your chainsaw for possible compression issues like an air leak. Lay the chainsaw flat and tow the starter rope to check for compression. Try taking the plug out to air out the cylinder. 

Your chainsaw is on low compression if you notice the rope extending when you draw it. Getting help from a professional mechanic is the best option to fix compression. 

When to Consult a Repair Professional

If you’ve gone through all the common issues I’ve outlined and your chainsaw still isn’t functioning as it should, I’d advise taking your saw to a professional mechanic for a more specialized diagnosis and repair.

person repairing a chainsaw

There may be more complex issues with the engine itself or compression problems with the starter, and professional help is the only advisable fix.  

How to Start a Flooded Stihl Chainsaw

Properly utilizing the chokes on a Stihl chainsaw can be a game-changer when it comes to cold starting. Here’s a practical tip I’ve learned through experience:

When you close the choke, it’s essentially telling the carburetor to release that extra fuel into the chamber, making it easier to start in colder conditions.

Now, here’s a common mistake I’ve seen chainsaw users make time and again: they keep pulling the starter well beyond the standard three to four pulls. 

This can lead to a flooded engine, as it ends up with an excess of gasoline. So, remember to give those chokes a chance to do their job before you start yanking that starter cord repeatedly.

checking a chainsaw's flooded engine

Here’s an easier fix instead of waiting for the fuel systems to drain.  

Step #1: Switch to Cold Start Position

Break on the chain, and turn the choke off to decrease resistance. Switching to a cold start makes starting a flooded Stihl chainsaw that won’t idle much easier. 

Move the selector back to the furthest back position by pressing the safety catch and trigger the throttle quickly. Disassemble the top cover, plug, and control lever.  

Step #2: Inspect the Spark Plug for Damages

One telltale sign of damage in a spark plug is chunky carbon build-ups on the ends spanning the gap. A faulty spark wire can cause your engine to sound rough or not start. Unscrew the plug using the provided wrench. Clean these parts with a wire brush with little gas. 

Stihl chainsaw defective spark plug

Inspect for possible leaks, and wipe the wet spark plugs. If there are damages like ceramic cracks, replace the spark plug. Also, check for broken wires that can lead to trouble starting the engine. 

Step #3: Switch to Warm Start Position

Move the master control directly to the run position for a warm start.


Are Stihl Chainsaws Powered By a Mix of Gasoline and Two-Cycle Oil?

Stihl Chainsaw engines run on a mixture of lubricating oil and gasoline. However, you have to reach the correct ratio for efficiency, or else you’ll end up with a poor-performing engine. Mixing correctly also prevents piston seizing and expensive engine repairs. The expert fuel-mixing proportion is 50:1 oil: gas. 

Is there a trick to starting a Stihl chainsaw?

To start a Stihl Chainsaw, adjust the Stihl chainsaw carburetor by releasing the primer bulb twice. Shift the lever to a full choke position three to four times. And draw the starter rope six times maximum to start the engine.


A worn-out carburetor or a faulty spark plug are often the main culprits when a Stihl chainsaw refuses to start. But given the intricacy of this power tool, it’s understandable if any user finds it challenging to pinpoint the exact problem.

While the tips I’ve provided should offer some guidance in addressing stubborn Stihl chainsaw issues, if problems persist, seeking professional assistance is the way to go. I’d recommend taking it to your local Stihl dealer for repairs.

robert headshot

Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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