Why Does My Chainsaw Bog Down When I Give It Gas?

This issue can be corrected by manual adjustments of the carburetor and fuel supply. But first, you need to know the basic knowledge of the engine working and adjustments.

A working engine requires routine maintenance and tuning of the engine parts to keep them working and to improve the health and life of the engine. Any laziness can result in the form of engine bog down or warms up of the engine.

It is a common problem of every type of engine no matter if it’s a lawnmower, Stihl chainsaw, or Husqvarna chainsaw. The most common problem of engine bog down comes around in lawn mowers that start then dies

Similarly, the chainsaw engine bogs down when you give it gas and that can be due to an unbalanced supply of fuel from the carburetor. The carburetor has many adjustments of screws that work for various speed works and the non-adjustments of these screws results in form of engine bog down.

In this guide, I will answer you that “why does my chainsaw bog down when I give it gas?” Furthermore, all the engine adjustments to recover the engine bogging down are discussed in the guide too.

Let’s move to guide.

Main Reasons Why Chainsaws Bog Down When Given Gas

The chainsaw bogs down during gas intake due to the unbalanced supply of fuel. There are many possible reasons for chainsaw bog down when you give it gas. 

Here are some major reasons chainsaws bog down when given gas:

1. Low air supply

The air supply is a crucial thing in any internal combustion engine and a little unbalanced in the air supply due to internal and external factors can result in form of engine bogging down. 

The low air supply to the engine during the gas intake to the engine can partly be attributed to clogged filters and less air supply to the carburetor.

That problem can be accompanied by the smoking of rich fuel and oil mixture. 

Solution: The solution to this problem is by using compressed air to clean the carburetor jets and passages to ensure an efficient air supply to the carburetor.

2. No use of fuel stabilizers

The use of Fuel stabilizers is much crucial for the chainsaw owners that leave the equipment with the non-empty fuel tank. The rest fuel in the fuel tank forms the gum-in tank that clogs the fuel lines and carburetor that ultimately results in form of less supply of fuel for complete combustion to run the saw.

That will cause the chainsaw engine to bog down when you give it a new try at work and it will cause bogging down when you give it gas. The engine will start normally but bog down again when you give it gas.

Solution: The best solution to this problem is to use fuel stabilizers along with fuel. They will help in preventing gum formation in fuel tanks. 

3. High ethanol percentage in fuel

The high composition of ethanol numbers in fuel is another reason for stalling of the engine. Ethanol has the property of ready vaporization and forming the water by absorbing the moisture from the air. That water causes the stalling of the engine while you get the gas in the engine.

The fuels containing 10% ethanol have a tendency to separate the varnish from the gas that can result in a form of accumulation in fuel lines and tanks. While the residual counters the combustion in the carburetor.

4. High-Speed Screws Not Alligned

The carburetor has three adjustment screws, one for idle, low speed, and high speed. When the high-speed screw of the carburetor is open too far, it will result in the form of an excessive supply of fuel in the combustion chamber.

The more fuel entered in the combustion chamber due to wide opening by high screw will not ignite completely and gives poor performance.

The residual fuel will produce smoke that fouls the spark plug and air filter and the engine will start problems in the form of bogging down and stalling during work.

Solution: To overcome the problem of engine stalling due to faulty adjustment of the high screw is by closing the high screw. But too lean a fuel supply can also create problems for engine efficiency and overheats and pistons can seize.

It is much difficult to adjust the proper high-speed adjustment by ear so it is better to use a tachometer for this adjustment.

5. Dirty Carburetor

The dirty carburetor is the major reason behind the bogging down of the engine. But in the case of engine stalling during the intake of gas is due to faulty adjustment of carburetor screws. These screws control the balanced supply of fuel to the combustion chamber and little more or less results in engine stalling.

When idle, adjusting the idle screw is a corrective measure to correct the chainsaw stalling. While the inability of the engine to reach the full-throttle trigger results in bogging down of the engine. Adjusting the high-speed screw is the remedy to this problem.

chainsaw carburetor adjustments

Chainsaw carburetor adjustments

What do the L and H mean on a chainsaw? 

The “H” sign on the carburetor shows the high-speed adjustment and this screw regulates the fuel/air mixture that passes to the combustion chamber of the engine. 

While the “L” sign on the carburetor means the low-speed adjustments that regulate the fuel/air mixture when passes to the motor around low rpm’s.

What is the T adjustment on the chainsaw?

“T” labeled screw-on carburetor works for the idle speed adjustment to accelerate the chainsaw smoothly. Adjust the T screw with a flat head screwdriver by turning in a clockwise direction until the chain starts moving.

How to Prevent Your Chainsaw from Bogging Down when give it gas?

Correction of the stalling measure of bogging down chainsaw engine is referred to as tune-ups. These procedures will correct the stalling of the engine as well as improve your chainsaw performance.

But you need to learn the basic adjustment of spark plugs, carburetors, and filters of chainsaw engines. 

Here are some techniques to prevent your chainsaw from bogging down when give it gas:

Spark Plugs

Spark plugs have a crucial role in defining the fuel economy of an engine. A sooty plug indicates the rich fuel mixture that results in frequent stalling and misfiring.

Burnt spark plugs will cost you more in the form of too high combustion and high ethanol concentration, which results in the form of a stalling engine.

The best practice to prevent your chainsaw from stalling is to replace the sooty plug with a new one.

Carburetors and filters

After cleaning the spark plug and ensuring that it is good to go, then go for checking the carburetor adjustments and air and fuel filters. Here is the complete method to adjust the carburetor and filters to prevent the engine from bogging down during the intake of gas.

  • Make sure to add the fuel stabilizers every time you start to work with your chainsaw. Let the engine run for some time so it flushes gunk out of jets completely.
  • Clean the fuel tank completely and clean any debris or dust from the tank.
  • Now inspect the fuel line condition and replace the old fuel lines to get more efficient.
  • Replace the air filters located in the fuel tank.
  • Check for the adjustments of the three screws on the carburettor. Adjust the screws accordingly to your work. If the carburettor is in much faulty condition, replace it with a new one.
  • Clean the carburettor with thinner to clean the gum buildup by no use of fuel stabilizers. Make sure to use a thinner for cleaning the carburettor and clean it after removing it from the engine body.

If it still creates a problem then now it’s time to go for a professional.


Why does my chainsaw die at full throttle?

The incorrect adjustment of the high-speed screw is the reason for the chainsaw stalling at full throttle. The remedy to this problem is adjusting the high-speed screw.

Why do my chainsaw bogs down during cutting?

The reason behind the bogging down of the chainsaw engine during cutting is the not adjusted high-speed screw. It causes an inefficient mixture of fuel/air supply that causes stalling of the engine during cutting.

Why does a chainsaw lose power when hot?

The chainsaw loses its power when hot or under full load due to the improper mixing of fuel and air in the combustion chamber of the engine. To prevent this problem, adjust the fuel and air supply on the carburetor by adjusting screws.

Why does a chainsaw start then dies when you give it gas?  

The major reason for chainsaws bogging down or stalling is the dirty carburetor. Firstly, clean the carburetor and if it doesn’t work, go for the rebuild and replace it. 

The other reason chainsaws don’t stay running is the bad fuel filter. The clogged fuel filter causes the problem in the engine running and it’s better to replace it with a new one.

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