Briggs and Stratton Engine Starts but Won’t Stay Running! (Causes and Solution)

You’re getting ready to mow your lawn with Briggs and Stratton mower! Suddenly, you discover the engine starts but dies off at once. What is the cause behind it?

A dirty or clogged carburetor is a very common cause of engines that won’t stay running. You may have to clean or replace it.  A dirty air filter, defective spark plug, and bad fuel also can be the cause why Briggs and Stratton engines start but won’t stay running! 

Let’s try to figure out what problem you need to solve with your troubleshooting guide. I hope you’ll get your mower working back! 

Briggs and Stratton engine
Briggs and Stratton

4 Causes Why Briggs and Stratton Engine Starts but Won’t Stay Running! 

After a few failed attempts at running your Briggs and Stratton mower, please take a break! You have to inspect the relative parts which can prevent the start of the engine. After finding the cause of the lawn mower parts, you’ll easily fix this problem. So, check the common cases first-

1. A Dirty Carburetor 

The main culprit is the dirty carburetor behind the engine won’t stay running. Basically, a carburetor function is to provide the correct mixture of air and gasoline for combustion which helps to start the engine.  If the carburetor float bowl or nut gets clogged with dirt, the engine can’t work properly. 

Dirty Carburetor 
Dirty Carburetor 

Related Post: Briggs and Stratton Timing Problems – Reasons and Fixes Explained

2. Defective Spark Plug

Well, you can’t ignore the steps of inspecting the spark plug. Sometimes, it gets ineffective to produce enough spark to run the engine. As it gets clogged with dirt, oil or residue. 

 Spark Plug
Spark Plug

3. A Dirty Air Filter

A dirty air filter might be the cause of the engine not staying running.  The air filter helps to give the engine enough air to start.  If it gets clogged with dirt or other residues, then the engine acts as if it won’t run.

 Air Filter
Air Filter

4. Bad Fuel

Bad or contaminated fuel can be the other reason for the engine’s issue. If you have bad fuel or oil in the gas tank, drain it quickly. Otherwise, it prevents the engine from starting.

Related Post: Briggs and Stratton Oil Leak Problems! How to Solve Them?

How Do You Fix a Lawn Mower That Won’t Stay Running?

After knowing the common issues, it’s time to inspect the parts and fix them quickly. Therefore, you need to follow the basic steps which are given below-

Step 1: Check the Fuel

First, you need to check if the fuel is contaminated or not!  If the fuel is in bad condition,  then drain it out.  Refills the gas tank with fresh fuel.

Step 2: Check the Air Filter

The next part you should check is the air filter. If the air filter is clogged with dirt, oil or residue, then clean it with a carb cleaner. Try to start the mower, if it’s not working, then spray some starting fluid. Check again the condition. If the step fails to start the engine,  try for the next one.  However,  the best option is to replace the air filter rather than cleaning! 

Step 3: Check the Spark Plug

A dirty spark plug somehow prevents the engine from starting. If you discover some carbon buildup on the spark plug or oil & residue, clean it quickly. If it’s simply clean, then try to start the engine. If it gets much dirty, then replace it with a new one

Step 4: Check the Carburetor 

First, you need to remove the carburetor. Therefore,  remove the hoses and linkage with a screwdriver or pliers. Remove the carburetor and check whether there’s dirt on the outside clamp or not. Remove the dirt with compressed air. 

Next, try to remove the carburetor float & other parts to separate the carburetor from the mower. Now, clean the carburetor by spraying a carburetor cleaner. Clean out the remaining residue or dirt with a cloth. Now, dry the carburetor and reattach the parts of the carburetor. 

Related Post: Briggs and Stratton Gas Cap Problems: 5 Things to Fix

Frequently Asked Questions (FAQs):

Why does my lawn mower only run for a few seconds then dies?

The most common reason for an engine to start and then dies is a clogged or dirty carburetor. Again, defective spark plugs, old gasoline, and dirty air filters may cause engine problems.

How do you clean a carburetor on a lawn mower without removing it?

You can clean a carburetor with a spraying carburetor cleaning without removing it. Just spray the cleaner on the inside and outside of the carburetor. 

Will WD-40 clean a carburetor?

Using WD-40 will effectively clean your clogged carburetor. It will reduce the extra time and energy required to clean the parts of the carburetor. 


Maybe! You don’t notice the defective spark plug, dirty air filter or clogged carburettor. Check it out now! Clean out the parts and replace them if needed. That’s all for fixing your Briggs and Stratton engine.

Moreover, inspecting every part after using a lawn mower is very important to ignore such ridiculous issues in future. Hopefully, you’ll give your lawn mower proper maintenance.  

That’s the end of the discussion.  If you want to get further information, contact me in the comment section. It’s time to say goodbye!!

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