Chainsaw Dies When I Give It Gas (Here’s What to Do)

Husqvarna, Poulan, Echo, and even Stihl chainsaws all have one thing in common: small gas-powered engines that are prone to problems. One of the common issues I’ve faced is that my chainsaw dies when I give it gas. So, if you’re like me and have found yourself pulling your chainsaw throttle trigger and your saw dies, then here’s what you’ll need to take a look at to get your saw cutting again.

Why Does My Chainsaw Stall When I Give it Gas? (The Short Answer)

A chainsaw engine that dies when it is throttled up is typically facing several common maintenance issues. These problems can include an air filter blocked with debris, a fuel filter blocked with debris, a worn-out or sooted-up spark plug, an incorrect fuel-to-air setting on the carburetor, or bad gasoline in the chainsaw.

Chainsaw Dies When Giving it Gas  (A Closer Look At The Reasons Why)

Chainsaws are subjected to some pretty harsh working conditions that tend to lead to problems with the engine. So, even if you take care of your chainsaw meticulously, you’re still going to run into some potential problems. Here are my top five reasons your chainsaw stalls when giving it gas.

Air Filter is Clogged

The air filter on a chainsaw has the really tough job of keeping out all of the sawdust. I’d say that the chainsaw is subjected to probably the dustiest working environment out of all the tools in the shed. Also, being that the tool is so compact, there isn’t much room to protect the air filter from contamination like there is on a lawn mower.

Once the filter becomes clogged, the chainsaw can no longer get enough air into the carburetor, and the air-to-fuel mixture is thrown off. This means that when you give the chainsaw gas, it can’t get enough air, and it dies. So, remove the air filter cover and inspect the filter.

Fuel Filter Clogged With Junk

You have probably already noticed that the gas tank and the fuel filter are pretty small on a chainsaw. So, it’s understandable that it doesn’t take much to get dirt in the tank when you’re fueling up. Especially with all the dust in the air from cutting.

So, either hook out the fuel filter or tip it out if you have an empty fuel tank and see what condition it is in. If it is discolored or clogged, then you’ll need to get a replacement. A clogged fuel filter on your chainsaw will reduce the flow of fuel to the carburetor. When you pull the throttle, the engine will end up getting a lot of air but very little gasoline.

Again, this is an alteration to the fuel-to-air mixture that the engine doesn’t like. Hence, your chainsaw dies when you give it gas.

Fuel-to-Air Mixture

While we’re on the subject of fuel mixture, let’s take a look at the mixture adjustment on the carburetor. There are three adjustments you can make to adjust the low RPM (revolution per minute), high RPM, and idle RPM.

The reason you’ll find yourself needing to make these adjustments is that the chainsaw is subjected to a high amount of vibration that can result in the chainsaw adjusting itself, plus things like the air filter degrading over time.

So, you can test these settings by using an RPM tachometer, such as a Stihl EDT9 or an Echo GE. These devices measure the RPM the engine runs at different engine speeds. If you find that your settings are off, then it’s highly likely that this is the reason your chainsaw dies when you give it gas.

Stihl MS880 Example Carburetor Settings

• Low is to be set to just above stalling point
• High is to be set to 11500 RPM
• Idle is to be set to 2700 RPM

Sooted Spark Plugs

It’s possible that you could have an old or damaged spark plug in your chainsaw, but I find that the plug being sooted up is more likely. This is because, with all the alterations to the fuel-to-air mixture and changes to the carburetor settings, the engine often runs too rich and produces higher carbon deposits on the plug tip.

Therefore, when you give the engine more gas, the spark plug struggles to make the spark it needs to keep up with the engine. So, grab a spark plug socket and remove it from the engine. You’ll want to check the condition of the spark plug tip to see if it looks coated in carbon.

Also, this is a good time to check if the plug is gapped correctly. If the spark plug doesn’t look right, you’ll either need to service the spark plug or install a replacement.

Bad Gasoline in the Chainsaw

Contaminated or bad gasoline is certainly going to cause your chainsaw to have combustion problems that can result in your saw dying when you give it gas. Chainsaws tend to be a seasonal tool that usually hang around in the shed most of the year.

So, if they are left with gasoline while stored, then the fuel goes stale. This basically means the fuel starts to lose its ability to ignite. So, when you increase the fuel flow by pulling the throttle trigger, the fuel can’t ignite well enough to keep up.

In addition, as the fuel goes bad it starts to form a varnish that attaches to the inside of the engine, including the inside of the carburetor. Try tipping some of the gasoline from the tank into a clear container, like a glass, and then do the same with fresh gas. If the gas from the chainsaw has a darker yellow or brown color, then it means that it’s stale and needs to be changed.

Also, you might find that the fuel has coated the inside of the carburetor. Therefore, some carburetor cleaning will be needed.

How to Fix a Chainsaw that Stalls when You Give it Gas

Now that we’ve gone over the possible reasons why your chainsaw dies when you give it gas, it’s time to move on to the fixes. Let’s take a look.

Cleaning the Air Filter

If your air filter is clogged up with sawdust, then you should be able to blow it out using an air compressor or even your leaf blower. This is normally enough to get the filter back to a pretty good level. But if your filter is contaminated with oil as well, then you’ll want to swap it out for a new filter.

So, for chainsaws like Stihl and Husqvarna models and many other saws, you just loosen the air filter screw/s by hand and lift off the air filter cover. Then, pull out the air filter. Now, you can either give the filter a blast of air from your compressor or grab a new filter. Then, position the filter onto the chainsaw, replace the cover, and install the screws/clips.

That’s really all there is to it. I guess manufacturers make this an easy process because they know the operators will need to clean the filters a lot.

Tools & Parts to Clean/Replace an Air Filter

• Replacement Air Filter if Required
• Air Compressor/Leaf Blower

Changing the Fuel Filter

The first thing you need to do before you change the fuel filter is to empty the gas tank on your chainsaw. First, funnel the gas from the chainsaw into an empty container. Next, you need to hook the fuel line and filter from the gas tank. If you happen to buy a Stihl fuel filter placement pack, then these come with a hook included. If not, then a length of wire with a bent end will work fine.

So, hook the fuel line and pull it slowly from the fuel tank. Just be careful not to pull too hard, as you don’t want to disconnect the line from the tank. When you can, grab the old fuel filter and remove it from the tank. Then, pull the old filter from the fuel line and set it to one side. Next, push your new filter onto the fuel line, then drop it back in the tank.

Just be sure to push the fuel pipe fully onto the filter so it doesn’t fall off later.

Tools & Parts to Replace a Fuel Filter

• Fuel Container
• Fuel Funnel
• Small Hook
• Replacement Fuel Filter

Setting the Chainsaw Carburetor

The carburetor settings vary between chainsaws, so you’ll need to look in your user manual and find the specific setting for yours. I’ll use the Stihl MS880 as an example and go over what tools you’ll need.

Setting the Chainsaw High Carburetor Screw

1. Start the chainsaw with the chain and bar installed.
2. Place the RPM tachometer close to the spark plug cable.
3. Pull the chainsaw throttle to maximum RPM (for no more than a few seconds).
4. Turn the high screw until the tachometer matches the required RPM.

Setting the Chainsaw Idle Carburetor Screw

1. Start the chainsaw with the chain and bar installed.
2. Place the RPM tachometer close to the spark plug cable.
3. Let the chainsaw sit at idle speed.
4. Turn the idle screw until the tachometer matches the required RPM.

Setting the Chainsaw Low Carburetor Screw

1. Start the chainsaw with the chain and bar installed.
2. Let the chainsaw sit at idle speed.
3. Turn the low screw until the RPM drops to just above stalling.

Tools Required to Set the Carburetor

• Chainsaw RPM Tachometer
• Screwdriver

Swapping Out the Spark Plug

When checking your spark plug, you removed it from the chainsaw. This included removing the engine cover, disconnecting the spark plug cable, and then removing the old spark plug using a plug wrench. So, you’re halfway done with the fix already.

Next, you’ll need to find a replacement spark plug. I strongly recommend that you look in your user manual for the exact spark plug your chainsaw needs. It’s very easy to get a spark plug that looks right but is actually totally wrong. So, take your time and figure out the spark plug you need. Then, reverse the steps you used to remove the old spark plug and install the new one. Lastly, install the spark plug, attach the cable, and then install the cover.

Tools & Parts to Replace a Spark Plug

• Spark Plug
• Spark Plug Socket Wrench

Removing the Bad Gas & Cleaning the Carburetor

To get the old fuel out of your chainsaw, tip the fuel into a fuel container using a funnel. This will get rid of the problem of old fuel. Then, just go ahead and fill the tank with fresh new gasoline mixed with the appropriate fuel-to-oil mixture. Fire up your chainsaw and let it run for a minute or two.

Next, give the chainsaw a try and see how it performs. Hopefully, the problem is solved. If it’s not, then you’ll want to clean the carburetor. The first approach is to use a spray carburetor cleaner which is usually enough to get rid of fuel varnish.

So, switch off the chainsaw and remove the air filter cover and the air filter. Then, start your chainsaw and spray the carburetor cleaner directly into the carburetor. It only needs a quick spray. Next, give the carburetor a minute to work through the cleaner, then give it another spray.

After a couple of sprays, you can put the chainsaw back together, including the air filter and its cover. Then give the chainsaw another try. Hopefully, this process will be enough to clean out the old fuel issue. If not, then you’ll need to remove the carburetor and do a deep and thorough cleaning.

Tools & Materials to Remove Old Gas and Clean the Carburetor

• Fuel Container
• Fuel Funnel
• Fresh Gas
• 2-Cycle Oil
• Carburetor Spray Cleaner