How To Fix A Stuck Float On Lawnmower

How To Fix A Stuck Float On Lawnmower? [Step-By-Step]

7 minutes

A stuck float on a lawn mower can cause the engine to produce black smoke or shake unnecessarily. 

When either of these occurs, you may think that there is a fire somewhere in your engine, or that it is damaged, but a stuck float could be the reason behind these scenarios. 

To find a solution to these problems, it’s important to know how to fix a stuck float on a lawnmower. 

In this article, we will discuss this topic in-depth to help you with the repair.

Let’s get started! 

How To Fix A Stuck Float On Lawnmower: An Ultimate Guide

When the float is stuck, it’s either providing too much fuel to a particular cylinder or the cylinder isn’t getting enough fuel. However, you might not be able to locate where the actual problem is. We’ll be outlining the cause and solution to this issue.

What Is A Float Of A Lawn Mower?

The gasoline is supplied by a fuel pump to the float bowl, which stores the fuel before it is combined with air. 

Within the bowl, there is a float needle valve. The float gets low and the valve opens up to add more fuel when the fuel level dips below a specified level.

The float rises when the float bowl is full, and the needle valve closes down, stopping the flow of fuel. When the float gets stuck, it makes the supply of fuel irregular and inconsistent. 

What Causes The Float To Get Stuck?

Poor fuel quality is generally the main culprit behind a stuck float. Apart from this, the most common causes are varnish on the float, which clogs up the valve; a distorted needle valve that does not always seal well; or debris in the carburetor’s bowl.

How To Know When The Float Is Stuck?

If you notice any of the below symptoms on your lawn mower, these are clear indicators that the float is stuck:

  • The engine will halt even if it is not moving.
  • When the engine will not idle, it’s an indicator that the carburetor float is stuck.
  • The engine stalls or pauses.
  • The engine’s cylinder is unable to produce power/engine misfire.
  • The carburetor is flooded.

How To Fix A Stuck Float On A Lawnmower?

A stuck float can be fixed in two ways: a permanent repair or a temporary repair. We will discuss both of them in the following part.

Required tools

Permanent repair

To fix the problem permanently, follow the steps as mentioned below:

Step 1: Turn off the gas supply 

Remove all of the gas from the tank. Unplug the tank’s fuel supply line.

To prevent any overflow from the remaining gas in the tank, use a fuel stopper or a clip. These clips are usually made of plastic and are known as fuel clips. The fuel stopper is more advanced than fuel clips and provides better protection. However, you can use either of them. 

To prevent any remaining gas from spilling, set up a collector pan. This pan is specifically made for collecting fuel from the engine. 

Unplug the air filter and clean it as well. To unplug the air filter, you will have to firstly remove the cover of the filter. To do that, you can use a Phillips head screwdriver. 

Use hot water and liquid soap to clean the air filter. Once all the grease is gone, drain the extra water carefully and let it dry. Then add a small amount of engine oil to the filter. 

Step 2: Remove the carburetor 

Use a screwdriver to remove the cover of the carburetor. Remove the screws to detach the air filter housing.

Use pliers to detach the air vein’s spring. Use a 3/4  socket or nut driver to remove the carburetor mounting bolts.

Detach the carburetor from the throttle rod.

Step 3: Drain the fuel from the carburetor

To release all of the gas from the carburetor, loosen the drain plug in the carburetor float. 

Collect the gas in a collecting tank and mop up any splashes, if there are any.

Step 4: Remove the carburetor float

Remove the carburetor float by unscrewing it and pulling it out.

Step 5: Remove the pivot pins

Push the pin that is securing the float assembly, from one side with pliers or screwdriver. Now, pull the pin out with tweezers or pliers to remove the float.

Step 6: Examine the needle valve

Using a flashlight, look for a needle valve that may be clogged, which is likely creating all the problems.

Step 7: Clean the float

Use the carburetor cleaner. Thoroughly clean both the inside and outside of the carburetor. Clean off all apparent dirt by using a cotton swab.

Step 8: Replace the floating gasket 

Check to see whether the float’s gasket is damaged. If this is the case, the gasket should be replaced. 

Remove the marking that the old gasket has created before reinstalling the new one.

Step 9: Reassemble and recheck

Any element that appears to be damaged or worn out should be replaced immediately. 

Then reassemble all of the pieces.

Temporary Repair

A temporary repair is not the ultimate solution to this problem, but the engine may not need a full repair just yet. If you’re short on time and unable to do a full repair or don’t need to fix the problem immediately, you can make some temporary repairs. 

There are two methods to do this:

Method 1: Free the float using impact

Open the cover of the lawnmower and find the carburetor. Push the top of the carburetor with a screwdriver. Do not exert excessive effort while doing so. The carburetor can easily be damaged by too much pressure. 

Then, tap on the carburetor’s bowl area. As the dirt from the clogged piece falls away, this may help the carburetor’s float release itself.

Method 2: Drain the fuel to push the float

If your lawnmower has a fuel valve, close it. A fuel valve is a device that takes compressed liquid fuel and sprays the fuel into the engine’s cylinder. The needle valve directs fuel from the tank into the float chamber. 

Open the drain plug under the carburetor. To collect the fuel, place a fuel collecting pan under the carburetor.

The obstructing element can be removed and the bowl freed by a flow of fuel under force from the bowl. Reinstall the plug carefully and clean up any gas spills.

Method 3: Clean it by using carburetor cleaner 

Disconnect the intake pipe from the carburetor’s head. 

Clean the manifold and the top area of the carburetor using a carburetor cleaner. 

Allow 20–30 minutes for the dirt to drain from the plug and the carburetor to settle before restarting the engine.

Method 4: Blow pressurized air into the carburetor

Blow air from the top of the carburetor and keep the drain plug open in the bowl. This will remove the dirt that is clogging the float. 

Note: As these methods are all supportive of a temporary repair, they will not solve your problem entirely. You may have to go through two or three methods before solving your problem temporarily. These methods are great if you’re pressed for time and need a quick fix! 

Necessary Safety Measures 

Below is some safety measures we would advise taking when making any repairs to your engine: 

  • Always remove the spark plug before doing any repair on your lawn mower.
  • Make sure that the engine is not hot.
  • Release the starter rope from the retainer and pull the cover off.
  • Use safety glasses, gloves, and even safety boots.
  • Save the fuel in a collector pan. Be careful to ensure that the oil doesn’t splash on the ground or anywhere, this will help to avoid creating any fire hazard. 
  • Perform the task in the open air, for example: on your lawn. Also, have a sufficient source of light. 


Hopefully, this article on ‘how to fix a stuck float on a lawnmower’ was helpful. 

Remember, there can be confusion between a blown head gasket and the stuck float. If your engine has any problems with the head gasket, it will make noise and slightly emit smoke while running. On the other hand, if the problem is in the float, it will create smoke and stop instantly. 

Todd L Miles
Lawn Mowers Enthusiast
I started "Landscape and Lawns Care" to provide clients with lawn care with better service, better products and, most importantly, better ethics. My promise to every customer is to give the greenest grass possible while controlling weeds, insects, and diseases! The most important thing is that I strive to always do the right thing for you, your lawn and your wallet!