I was extremely frustrated when my chainsaw refused to start despite the fact that it had spark and fuel. I sought experts’ help, but they could not diagnose the problem.
Fortunately, through some digging, I found a couple of potential reasons that may be contributing to the issue.
A chainsaw may not start even with spark and fuel due to dirty spark plugs, carburetors, or air filters. The power tool will also not start if one of these components is damaged.
In the article, I discuss the potential problems and suggest ways to resolve them. I will also explain why chainsaws sometimes start but fail to run.
Let’s jump right in!
Problems That Prevent Chainsaws From Starting
Here are three problems that could hinder your saw even though it’s fuelled and sparking.
- Having A Dirty Spark Plug
A carburetor’s air-to-gasoline ratio can cause a dirty spark plug. If this is the case, a chainsaw will not operate even if it has enough fuel.
- Clogged Air Filter
An air filter’s primary function is to trap dust and debris and prevent them from getting into the saw. However, if you don’t clean it long enough, dirt will accumulate and clog it, making it impossible to start the saw.
- Improperly Maintained Carburetor
There is a possibility that gasoline varnish can get into the carburetor. In such a case, the jets become clogged, and the chainsaw will not start.
Solutions For A Chainsaw That Has Spark And Fuel But Won’t Start
If your chainsaw is equipped with fuel and spark but won’t start, look for a few things to figure out what’s wrong.
- First, ensure that the spark plug is clean and debris-free.
- Next, check the air filter to see if it’s dirty or clogged. If so, clean or replace it.
- Finally, check the carburetor to see if it needs to be adjusted or cleaned.
Regardless of the problem you discover, I have provided you with solutions in the following paragraphs. Take a peek at them.
Solution – 1: Cleaning the Spark Plug
When chainsaws have a spark and enough fuel, a dirty spark plug may prevent them from starting. Before you go ahead and replace it, you might want to clean it first.
Here is a quick and easy way to clean a spark plug:
STEP – 1: Detach the electrodes
The carbon on the electrode should be removed using an emery cloth. The other electrode emerges from the metal base on the opposing surface. You should also remove it.
STEP – 2: Clean the electrodes
Once you have detached them, scrub them with a wire brush. If stubborn deposits refuse to budge, scrape them off with a knife.
This should be enough to clean the spark plug thoroughly. If the issue still persists, it may be time to replace the item. A good thing about spark plugs is that they are quite affordable.
Solution – 2: Unclogging the Air Filter
Sometimes the chainsaw does not start despite replacing the spark plug. In that case, a clogged air filter could be at fault.
The following is a comprehensive guide to unclogging your air filter. Let’s see it.
STEP – 1: Take off the air filter
First things first, remove the air filter from the chainsaw. You should always avoid cleaning the filter while it is inside.
STEP – 2: Get rid of the dust
Now pick an air compressor to blow the dust away from the inside out. Be sure you blow inside out, not the other way around.
STEP – 3: Lower the air pressure
Another thing to remember is that chainsaw air filters cannot handle high air pressure. Hence set the compressor to its lowest setting, preferably below 20 psi.
STEP – 4: Keep a safe distance from the filter
Unfortunately, not all compressors come with low-pressure options. In that case, turn down the setting as much as possible and position the compressor further away from the filter.
Although this is an effective method of cleaning air filters, it may not work for some chainsaws. If you have such a filter, try cleaning it with soap and water.
Nevertheless, soap washing only works if your chainsaw contains a foam air filter, not a paper one.
Solution – 3: Cleaning the Carburetor.
Installed a new spark plug and cleaned the air filter, but still no luck? There is a good chance that the carburetor is to blame.
It is common for carbs to get dirty, especially if they are frequently used. Fortunately, you can clean them easily with a few simple steps. Let’s take a look at those.
STEP – 1: Clean the intake components
Cleaning the air intake components in your carburetor is the first step. You can speed up the process with a spray cleaner.
STEP – 2: Clean the needle valves
Secondly, you should clean the needle valves on the carburetor and drain the washing agents.
STEP – 3: Pause as you pull the chainsaw rope
Now gently pull the chainsaw’s rope with pauses. By doing so, the gummy residue will be dissolved by the fuel-cleaning agent mixture.
STEP – 4: Discard the old fuel
Last but not least, do not start your chainsaw immediately. Before turning on the machine, empty the old fuel and fill the tank with fresh fuel.
Finally got the chainsaw started, but now it is not running? Don’t worry; I’ve got you covered. Head over to the next section to learn why the problem occurs.
Also Know: Stihl 291 Vs. 311
Why Does My Chainsaw Start But Not Run?
If your chainsaw starts but won’t stay running, there are a few possible reasons. Here are those:
- The chainsaw is out of fuel
Check the gas tank to make sure there’s enough fuel. If it’s empty, refill it and try again.
- The spark plug is fouled
A fouled spark plug can cause the engine to start but not run smoothly. Clean or replace the spark plug and try again.
- The carburetor needs adjustment
An improperly adjusted carburetor can cause starting and idling problems with a chainsaw engine.
The next section will explain how to adjust the carburetor.
Why Is Fuel Coming Out Of The Exhaust On My Chainsaw?
If you notice fuel coming out of the exhaust on your chainsaw, it’s important to take action right away. If left unchecked, this problem can cause serious damage to your chainsaw and even lead to a fire.
The most likely cause of fuel coming out of the exhaust on your chainsaw is that the carburetor is set too high.
When this happens, the engine gets too much fuel and not enough air. This causes the engine to run lean and produce more emissions.
To fix this problem, you’ll need to adjust the carburetor.
First, consult your chainsaw’s manual to find the correct settings.
Then, use a screwdriver or wrench to turn the screws until you’ve achieved the correct mixture of fuel and air.
If adjusting the carburetor doesn’t solve the problem, there could be an issue with one of the seals in your chainsaw’s engine.
These seals prevent oil and fuel from leaking out of their respective chambers. If they’re damaged or worn out, they may need to be replaced by a professional mechanic.
To Sum Up
If your chainsaw won’t start and it has spark and fuel, you will need to check a few things. First, the spark plug must be clean, and its gap must be correct. Next, check the air filter and clean or replace it if necessary.
You can also check the fuel lines and ensure they are not clogged.
If you are looking for more articles on chainsaws, check out my piece about measuring chainsaw chains.