Stihl chainsaw Won't Start When Hot -Top 4 causes; guide

Stihl Chainsaw Won’t Start When Hot? 4 Reasons & Solutions!

So, you’re having a hard time starting your chainsaw. After several failed attempts, you finally notice it’s extremely hot. But it worked perfectly when it was cold!

Now you might wonder why the stihl chainsaw won’t start when hot.

Well, there might be several reasons behind chainsaws being hard to start when it’s hot. Maybe it’s the restriction of gas flow, it can be the fuel vapor lock or a dirty fuel filter. Yet, there are several ways to resolve it, as well. You may try unclogging any debris or dirt and make way for the trapped vapors. 

Still confused? I completely understand if you are. However, to clear up all your confusion, I’ve created this guide for you. 

Here I’ve detailed all the possible reasons why the issue is happening. Plus included some easy solutions for them!

Keep reading to find out!

Reasons Why Chainsaw Hard to Start When Hot And The Solutions

When working with a chainsaw, you may find it working perfectly when it’s cold. However, it won’t start that easily if it’s hot. 


There is not one but several reasons why the chainsaw turns hot. You need to be aware of all the reasons at first, only then you be able to successfully solve them. 

So, It’s very crucial to know how to start a hot chainsaw. Also, why does a chainsaw turn hot in the first place and their solutions?

I have provided a detailed snapshot explaining everything to you!

Reason 1: Fuel Vapor Lock

Vapor lock is the most common issue that causes the chain saw to die out. Vapor lock happens when exorbitant heat, as well as vapors, inflate inside the fuel tank. Plus, they are not ventilated properly. 

If the chainsaws are kept under the sun for a very long time, this problem arises. The increased heat results in unnecessary vapor buildup inside the fuel lines. It prevents the fuel from flowing freely in the carburetor. 

This produces a wiry mixture. And as a result, initially, the chainsaw might start faultlessly. 

However, the moment you rev it up, the elevated temperature further heightens the vapor pressure. This restricts the supply of fuel entirely. This causes your chainsaw to die out when it is hot.


So, how to fix a vapor lock? If you want to prevent the vapor lock problem from arising, ensure that the vents of the tank aren’t plugged with any debris or dirt because the job of these vents is to confirm that all the trapped vapors can be bypassed. 

If you are not sure if it is a vapor lock, next time your chainsaw won’t start, check for a vapor lock problem. For that, you have to unscrew the gas cap and try to vent all the gasses. Then attempt to restart the saw. 

If it turns on, you should understand that the issue was vapor lock. Now you will have to carefully examine the vent hole in the fuel tank. Notice if it’s clogged or damaged. Then, clean that hole using a cleaner and brush.

Moreover, keep the fuel cap open for some time. Then let the pressure neutralize. After that, close it and restart the chainsaw again.

Reason 2: Plugged Carburetor

Another issue is plugged carburetors. The chainsaw’s carburetor is the part where the fuel and the air are assorted with each other in the proper ratio.

This air-fuel mix is required to have a substantial proportion of fuel. Or you can say rich fuel mixture. 

Notice the subjects of your fuel. Keep in mind that they are most likely to result in white sticky residues over time.

These deposits may clog those carburetor jets. Thus they can obstruct the fuel supply to the engine. This could either be because of a dirty fuel filter or damaged fuel lines. A dirty fuel filter needs an immediate replacement.

 In due course, the engine will turn extremely hot and die out. Because it does not receive sufficient fuel to generate the necessary power. Especially, You will find this problem in husqvarna 562xp chainsaws.


To solve this problem, you need to invest in a repair carb kit including a carb cleaner. Then with that, you have to rejuvenate your carburetor. 

To clean the carburetor, first, you have to take it off. Start with discarding the air filter.

A carb cleaner spray can be very useful in this case. It helps in dislodging all those sticky deposits plugged in the jets. Thus making the carb function again. 

Just ensure that there are no fuel residues left once you are done cleaning the carburetor. Also, I recommend replacing your fuel filter and hoses regularly, usually once a season.

Reason 3: Defective Ignition

When the fuel lines, fuel filter, air filter, and tank vents are all good, the next to check out is the spark plug. This problem occurs when the spark plug electrode commences combustion by creating a spark in the engine. It mostly happens in chainsaws with Milwaukee batteries. To avoid additional problems you should properly store Milwaukee batteries.

This buildup reasonably occurs after prolonged use. It also affects the spark quality, especially at greater firing temperatures. 

If you find your homelite chainsaw not starting, it’s because of this issue.


To solve this problem, you need to replace the spark plug and clean the fuel filter. That is if the electrode seems worn out. A great way to test it can be by adding some starter fluid into the open choke valve, that can be seen under the air filter.

If your engine still does not start with the starter fluid, or it starts but stalls the problem is in the ignition module and it must be fixed.

Reason 4: Inadequate Compression

When working with a chainsaw, just remember that you always need to compress the air-fuel mixture. Compress it to a favorable temperature so that it can produce sufficient power in a power stroke. 

However, you may find Poulan chainsaws hard to start when hot. Because they utilize single-piston rings in their engines. So, these engines undergo a similar problem. If you investigate, you may find the ignition system and fuel delivery are functioning perfectly.

But, the piston ring of that engine might wear out to a certain extent. An extent where the compression infers at high temperature and might give a reading of about 0 psi. 


Normally, it’s the piston ring that prevents the gases from disappearing in the crankcase. Plus, it retains the pressure during a compression stroke. 

However, due to the thermal expansion, the piston’s wear rate heightens at a great temperature. That is why the high-temperature compression is nearly zero.


I recommend you conduct a compression test of the hot chainsaw. Do it before you start it. Also when it is cold and again after it is shut down because of the heat. 

For that, you can buy a compression tester gauge online. Or you can find them in any hardware store nearby. They are fairly cheap. 

So, you need to grab the tester and connect it to the spark plug socket. Then tug the cord in both of those two cases.

Look for any difference in the engine pressure between when it’s hot and when it is cold. 

If a contrast in pressure is found, it implies the error lies in the piston and cylinder. Based on the defect, you might have to get a new chainsaw.

You may try starting a warm Stihl chainsaw using this process.

Even after all of this, if your chainsaw fails to start then watch this video by TheRepairSpecialist-

This will give you an idea of what to do next. 

Chainsaw Preventative Tips and Cooling Techniques

  • Always check that the gas tank has enough fuel mixture
  • Dont put fresh fuel into a hot saw
  • Keep your battery chainsaw out in the dark, cool, and try to place


How do I start my chainsaw when the engine is warm?

To start the chainsaw, you need to first push the red switch to the up and on position. Then pull the chainsaw. Keep doing it until the saw starts. Normally, it takes 2 to 3 pulls. Avoid pressing the primer though. Also, refrain from pulling the blue color choke lever out.  

Can a dirty or worn-out carburetor make a chainsaw hot?

Yes, a dirty or worn-out carburetor may make your chainsaw hot. This causes the same issues in the engine. To solve this, you need to get the carburetor cleaned. If the carburetor is an older model, consider installing a carb kit. It will help with the fuel flow. 

Wrapping Up

Hope I’ve cleared up your question about why you find the chainsaw hard to start when hot.

Just try your best to identify the reason before you start resolving it. Go through this guide very carefully to see which indications match yours. Always remember to take safety measures when working with chainsaws.

That’s all for now. Have a good day!

1 thought on “Stihl Chainsaw Won’t Start When Hot? 4 Reasons & Solutions!”

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top