Lawn Mower Sputtering [Causes & How to Fix It]

A lawnmower is a simple machine that is used for cutting the grass in lawns. This machine is either hand-operated or motor-driven. Motor-driven lawnmowers give accurate results of cutting grass at less time than compared to handly operated lawnmowers. This makes your work easy until it is maintained properly.

Lack of proper maintenance doubles the very difficult work. With regular maintenance efficiency of the mower becomes better as it goes. Despite good and well-balanced methods for maintenance of the mower, they have some issues. One of the most common issues is the sputtering of the lawnmower.

Sputtering, in general, indicates an underlying problem that needs immediate attention. This problem is most times incomplete combustion in the engine or a blocked fuel injector. When it comes to lawnmowers, the sputtering sound usually indicates a small issue that needs to be tackled immediately to avoid the machine stalling.

Lawn being an open place lawn mower experiences sputtering. It is an easy fix that is not expensive and can be done as part of routine maintenance of the lawnmower.

Before getting into the detailed study of causes and ways to fix the sputtering one needs to understand the working procedure of a lawnmower engine.

Lawn Mower Engine

It has a very simple mechanism which is like that of a car engine. This engine is smaller than a car engine. This engine has a manual starter where one needs to pull a rope couple of times before it starts. The rope spins the engine which ensures that enough air and fuel goes in with the help of a carburetor.

It has a flywheel that provides electricity to the spark plug. The spark plug ignites the fuel and air which leads to a controlled explosion that drives the piston down and rotates the crankshaft.

Causes for Lawn Mower Sputtering:

  • Old Fuel or the Wrong Fuel.
  • Clogged or Dirty Air Filters.
  • Dirty Fuel Filters.
  • A Bad Gas Cap.
  • That Carburetor is FILTHY.
  • Water in the Fuel Tank or Fuel Line.
  • Check the Spark Plug.
  • Your Carburetor Has Issues.

Ways to Fix

1. Old Fuel or the Wrong Fuel

Gas available at local gas stations has only 10% of ethanol which is impure and not good fuel.  Ethanol burns easily which melts the plastic parts of the engine which causes sputtering in lawnmowers. Still, you use ethanol-blended gas please buy a little.

The best way to fix this issue is by using ethanol-free gas which will make the mower work better as it gives a perfect start. This makes your lawnmower powerful. One of the best fuels is “4-cycle-tru-fuel” which is a bit expensive, yet it gives the best results.

This is available on both offline and online platforms. Change the old fuel to a new one by tipping the machine and collecting the old fuel in a container. Always try to avoid using oil-containing ethanol.

2. Clogged or Dirty Air Filters

Dirty air filters are one of the common reasons which make a lawnmower sputter. Dirt present in the apertures leads to carburetor and fuel filter which stops the flow of fuel supply to the combustion chamber. As there is a stoppage in fuel flow which causes trouble in starting the lawnmower engine. Ultimately lawnmower sputtering occurs.

Constant checking of filters whether any dirt is present or not. One needs to be sure about cleaning and replacing a dirty air filter. Extra care is taken while cleaning the air filter. Paper air filters need to be cleaned regularly as there are high chances of getting clogged. Replacing them is far better than cleaning. If the filter is the foamed air filter, then one can generally clean it.

Use a cloth and washing liquid and warm water to wipe the foam from the filter. Do with care so that it is not damaged. Need to dry the filter once it is washed. For a paper air filter remove regularly during summer to blow the dust from the derbies of the filter. Use one filter for three months maximum.

3. Dirty Fuel Filters:

Every filter gets dirty from time to time. Such filters cleaning at regular intervals. This is like that of air filters used in the engine. Clogged fuel filters prevent the flow of gasoline to the engine which can lead to a lack of fuel needed for proper functioning. This imbalance of air and fuel in your engine can cause your mower to sputter and run rough.

The best way to fix this issue is to clean at regular intervals before it becomes too dirty or old. Once it becomes old or too dirty, we need to replace it with a new fuel filter. Excessive cleaning of the filter is dangerous as it stops the flow of gasoline to the engine. So never wait before it is too late to replace the dirty or damaged fuel filters.

4. A Bad Gas Cap:

A well-conditioned gas cap is essential for the smooth performance of any engine. It covers the fuel or gas from expelling out. By filling gas than the limit damages the cap if it is done multiple times. If the cap is in bad shape or condition, there are chances of an oil or gas leak which can cause fire of the engine. A gas cap with improper venting allows too much air into the gas tank. This causes an airlock that stops the flow of gasoline to the engine, and it does not.

The best way to fix this issue is to always take care of the gas cap whenever you fill the gas or fuel into the tank. If you notice any small damage to the gas cap replace it with a new one without wasting even a single second. If you observe the vent hole is restricted, please replace it with a new one.

5. That Carburetor is FILTHY

As time passes the carburetor in the engine becomes old and dirty. Sometimes it becomes too dirty because of dirt particles or rust forming on it. Such a carburetor causes problems whenever we try to start the lawnmower.

Gunky deposits either on the apertures or on the carburetor. This gunky is formed from the byproducts of hydrocarbon and combustion. Such particles make the carburetor filthy which is harmful to a smooth performing lawnmower.

The best way to fix this issue is by using a carburetor cleaner spray which is available both on online and offline platforms. By using this spray on regular basis, it cleans the dirt particles or deposits. It also keeps the aperture and hoses clean of a lawnmower. This keeps the carburetor clean which increases the efficiency of a lawnmower. Be careful while cleaning.

6. Water in the Fuel Tank or Fuel Line:

The fuel tank is the heart of any engine. Fuel in that tank enables the functioning of any engine. It is like the case of a lawnmower engine. If there is any trouble while starting first check the fuel tank.

If there is any water or other liquid substance other than fuel. As water slows down the process of fuel ignition. Water in the fuel tank is sputter for a lawnmower which must fix at that very instant.

The best way to fix this issue is to open the gas cap and double-check. If water is found, then empty the fuel tank. Check thoroughly to ensure there is no droplet of water in the tank. Drain the tank. Fill the gaps in the tank. By doing this gas in the line works as normal which increases the efficiency of the lawnmower.

7. Check the Spark Plug:

A spark plug is the soul of an engine. A well-conditioned spark plug is essential for the engine. If the spark plug is worn or damaged, then it must be replaced with a new one. A damaged spark plug makes the engine difficult to start.

The best way to fix this issue is to replace them at regular intervals whenever you repair your lawnmower. Always use branded spark plugs suitable to that lawnmower that comes from the factory. Sometimes plugs of one brand do not apply to one brand of the lawnmower.

The cost of a spark plug is affordable which makes it easy to replace at the time of service. If the tip of the plug is found dirty, clean it with a wire brush. Insert again into the mower and reset the manufacturing setting.

8. Your Carburetor Has Issues:

Better the condition of a carburetor, better the performance of a lawnmower. It has many issues which sputtering in a lawnmower.

One issue is a bad mixture of air and fuel which makes the carburetor rough while running. It is necessary to use a good blend of air and fuel for the smooth functioning of the engine. Some carb cleaning spray is used if there is any simple dirt on it. As carburetor is tricky to maintain, it is good to seek professional help when you encounter major issues. Always reach a professional guy for cleaning or replacement.

The level of grass can also cause sputtering. If one side of the grass is high and the other is low which brings the mower in an awkward position. Always ensure that there is no caked grass at huge volumes. Use a wrench to remove the spark plug to prevent the mower from turning on while you work. Then scrape the excess grass using a scraping tool such as a paint scraper.

Never forget to get your lawnmower serviced at regular intervals. If you are servicing on your own follow all the steps carefully to prevent sputtering. If you are going for professional help, then there is no need to worry. Maintenance plays a crucial role that cannot be neglected. A well-maintained lawn mower can help in maintaining good grass on your lawn or backyard which gives a beautiful view.

Leave a Comment