Kohler Engine Dies When Hot (A Troubleshooting Guide)

Shocked as to why your lawn mower dies after being used for a while? It’s probably because it’s overheated causing it to seize up. However, it’s not a rare occurrence.

So, you might ask yourself why your Kohler engine dies when hot?

The most common reason is because of the vapor lock in the carburetor. Other factors such as old and insufficient oil can also be blamed. Even a faulty solenoid plug could be a culprit. Each of these problems can be fixed.

We are aware that this information isn’t inadequate. But don’t worry, we won’t stall you like your Kohler engine. 

Keep reading to find out why it does this and how to fix it.

Why Is Your Kohler Engine Stalling?

Before jumping straight into fixing your lawn mower, identify the reason behind this problem. This will help you fix the issue better. 

So let’s look at the three common culprits behind the issue.

1. Insufficient and Old Oil

One of the most prevalent causes of lawn mower overheating is low or old motor oil.

When a mower’s moving parts aren’t properly lubricated, they experience increased friction. This not only generates more heat but also wears down the parts much faster. 


The only way you can check if you have enough oil and its quality is to use a dipstick. The dipstick of your fuel tank will tell you the oil level in your tank. 

Faulty fuel is brown and cloudy, instead of being clear.

Solution and Prevention Technique

The solution to this is the simplest. You just have to replace the oil. 

As a prevention technique, always change your oil after the first 5 hours of use on a new mower.

Then at least once every spring/summer season, or every 50 hours of use. Depending on where you live, choose whichever comes first, as seasons may differ.

Remember to replace the oil filter as well as the oil. It’s recommended you use these specific oil-filters to replace the old ones-

2. Vapor Lock

Carbureted and air-cooled engines are particularly vulnerable to this problem. When the fuel (typically gasoline) in the fuel delivery system overheats it vaporizes too quickly.

This is when vapor lock occurs. This is when the gasoline goes out through the vents before it can go to the engine.


You don’t have to take the carburetor apart to see if you have this problem. You just have to check whether or not your cooler or condenser is working.

The way you can test this is by using a spark plug checker. You can check this by connecting the spark plug with the carburetor line. Next, turn the flywheel of your lawnmower.

If there is no spark, that means you have to change the condenser/cooler. This is more commonly known as a cooling coil


There is no prevention technique for this, you can only solve this by replacing the coil. You need the following tools to do this.

These are as follows-

  • Adjustable Wrench
  • Vice Grips
  • Screwdrivers

If you’re unsure about which screwdrivers to invest in, take a look at our picks below-

Now, let’s get to it!

First, pinch the fuel line with a pair of vice grips to turn off the gas to the carburetor. Then, using the screwdrivers remove the cooler from its resting place. Replace it with a new cooler/condenser.

Now, put a card between the cooler and flywheel. Next, rotate the cooler till the magnet pulls it into place. You will hear a click.

Then, connect the end of the tube to the carburetor and insert the sparkplug checker. Rotate the flywheel and you should see a spark.

Clean the carburetor with the cleaning solvent and wipe the debris off. Use a wire brush to do this. This means that your spark ignition is working.

If you’re in doubt, you could choose from our hand-selected bunch of carburetor cleaners-

3. Solenoid Plug

Here, the main root of the problem is the solenoid plug. When you turn the key on, it sends power to the solenoid. It pushes the plug down and allows fuel to go to your engine.

This stops the ignition from working altogether hence killing the power.


The diagnosis for this problem requires you to check the solenoid plug. It’s located under the carburetor. 

Now, when it gets hot or you shut off your mower, it cuts the fuel off. The solenoid has a rubber plug on the tip. Due to the excess heat and pressure, the rubber plug gets sucked into the carburetor. 


This does not require any tools and you can do it with your bare hands. Simply turn the solenoid anticlockwise. It will come off.

Replace the solenoid with a new one. Make sure the rubber plug is firmly placed on top of it. Turn the solenoid clockwise to connect it.

Your Kohler Engine should be running perfectly now. Run the engine for an hour or so to see if it still seizes up. If it does then you should take it to an actual mechanic.

So this is why your Kohler engine dies if overheated. Figure out your reason and solve the issue accordingly.

Frequently Asked Questions

Question: Why does my Kohler engine lose power under load?

Answer: Your Kohler engine may lose power under load for a variety of reasons. The issue might be anything from broken spark plugs to a clogged fuel line to low oil levels.

Question: What is the average lifespan of my Kohler courage engine?

Answer: The Courage engine will almost certainly never reach 2000 hours of operation. If you’re careful about how hard you run it and how often you replace the oil, you could get another 500 to 700 hours out of it.

Question: What is the best way to ice down my lawnmower?

Answer:  The best route to keep a mower cool is to park it somewhere safe and open where the muffler won’t come into touch with anything that could catch fire.

Bottom Line

Now you know why your Kohler engine dies when hot. If you’ve followed our instructions you can now stop your engine from overheating. This will allow you to mow your grass with ease.

Stay safe and say goodbye to your engine seizures!

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