Where to spray starter fluid in a lawnmower, step by step


If your lawnmower has been unused for some time, it can be challenging to start. Maybe you have neglected some of the maintenance, you did not properly winterize it, or there is some other reason. When a lawnmower does not start, you need to diagnose the cause. Mostly, the problem lies in a blockage in one of the engine components. Or a problem with the sparkplug. Using the starter fluid, you might start such an engine and diagnose the underlying issue promptly.

Where to spray starter fluid in a lawnmower, step by step:

  • Step 1: Locate the air filter housing
  • Step 2: Remove the air filter and clean
  • Step 3: Find the carburetor chamber underneath
  • Step 4: Spray the starter fluid
  • Step 5: Start the engine and diagnose
  • Step 6: Check, clean, and fix the part that causes the problem
Where to spray starter fluid in a lawnmower, step by step 1

What is starter fluid, and when to use it?

Starter fluid is a volatile and highly flammable mixture that contains rich hydrocarbon (fuel), diethyl ether, and carbon dioxide. Starter fluid is usually enclosed inside a pressurized can of spray. Upon pushing the trigger, in the presence of carbon dioxide, the starter fluid atomizes itself in the direction of the spray. Thus, increasing its tendency to react and mix properly with air.

Difficult to start

Lawnmower engines are smaller relative to car engines, but they can be trickier to diagnose than a car engine. A push-mower and most other mower types are normally fitted with a two-stroke or four-stroke engine, with one or two cylinders. If the mower is hard to start, this can be the result of a multitude of symptoms, ranging from a bad spark plug to bad fuel.

When to Use Starter Fluid

As the name suggests, starter fluid is used to start the engine when it is difficult to start. It’s beneficial when the engine is not used often and for cold-starts, like in the fall or early spring.

  • Engine Cold starts: Starter fluid can be used to improve starting the engine in cold weather. A low temperature can make starting your lawnmower really challenging.
  • Diagnosis of a starting problem: If there is an underlying problem why your lawnmower is not starting, you can use starter fluid to help diagnose it.

Learning how to use the starter fluid properly can save you a lot of time. If you still have any problems with it after reading this blog, ask a professional for help.

Where to spray starter fluid in a lawnmower

Required tools:

Spraying starter fluid is not a difficult task. You only need some basic tools to do it:

  • Wrench set
  • Screwdriver
  • Grip Pliers
  • Collector Pan
  • Cleaning cloth
  • Starter fluid

•Step 1: Locate the air filter housing

  • Lift the hood or remove the engine cover: If you are working on a riding mower, open the hood of the mower. In the case of a push lawnmower, you will have to find the cover’s latches, clips, and bolts. After locating, unscrew the bolts and undo the clasps. Lift the cover.
  • Locate the air filter housing: On the front of your lawnmower engine, you will find a black box with an opening shaped like fins. This box houses the air intake and air filter. This will bring the air to the carburetor, where it will be mixed with it and present to the carburetor for fuel mixing.

•Step 2: Remove and clean the air filter

  • Pull the cover off: Mostly, the black cover of the air filter housing is fixed with latches and comes off quite easily. Just make sure not to break the plastic. In some mowers, the cover is fixed in place using fasteners. These can be untightened using a socket wrench.
  • Locate the filter: Underneath the cover, a meshed filter is present. It is a foamy soft filter or a paper filter.
  • Remove the filter: The filter is normally easy to remove. Some filters use a bolt. In that case, use a torque wrench, unscrew the bolt and pull the air filter out. Make sure not to damage it as the filter is quite delicate.
  • Clean the filter: If you have a foam air filter, clean it. First, remove any apparent debris and mud by carefully tapping on it. The air filter can be cleaned dry as well as washed. If you are in a hurry, you can dry clean it with a vacuum. Be careful not to damage the air filter. If you have more time, use some dishwashing soap or detergent to wash it. Let it dry completely before using it. You can also use pressurized air to clean it. But careful if you use an air compressor. The strong air can quickly damage the air filter. If you have a paper air filter, it needs to be replaced.
  • Replace the filter: If the foam air filter is damaged or has a paper air filter, you need to replace it. Ensure that the replacement filter is the correct type for your lawnmower.

•Step 3: Locate the carburetor

  • Locate the carburetor: Often, you can find it behind the air-filter housing’s backplate. If you follow the fuel line from the gas tank, you can easily locate it. In the carburetor, the air from the air filter and the gas are mixed and send to the engine.
  • Clean the externals: If you have the time, it is a good idea to spray some carburetor cleaner into the visible ports and grooves and clean them with some cleaning cloth. The cleaner the carburetor is, the easier your lawnmower will start.

•Step 4: Spray the starter fluid

With the air filter and carburetor cleaned, it is now time to use the starter fluid:

  • Clean the housing’s backplate: Using a clean cloth and some all-purpose cleaner and clean and dry the area.
  • Locate the intake duct: In the housing’s backplate, there is a cutout from where air enters the carburetor. This is the intake duct that will lead into the breather tube.
  • Spray the starter fluid: In the found opening, spray a hefty amount of the starter fluid. Thus, the starter fluid is entering the carburetor chamber. https://www.youtube.com/watch?v=dCu2NYUm5vk

•Step 5: Start the engine and observe

  • Adjust the idle and choke: If adjustable, adjust the throttle to halfway. Lift the choke to full. This will increase fuel intake a lot.
  • Try to start the engine: Pull the starting cord or turn the ignition switch. With the starter fluid, the engine should start. Observe closely what is happening.
  • Observation: If the mower keeps running and does not shut down on its own, it is a good sign. But in most cases, a stutter accompanied by the engine stopping is observed.

•Step 6: Perform the cleaning and repair of the part found guilty

Now that we have observed what happened, we can diagnose the two options further:

  • Option 1: Engine stops within 3 seconds
    There is a problem with the carburetor. It should be adequately cleaned, adjusted, and, if needed, repaired.
  • Option 2: Stalling time between 3 and 30 seconds
    This indicated that there is something not ok with the fuel. It can be that either water is mixed, the fuel is dirty, or the gas is bad. To fix the issue, empty the fuel tank and carburetor. Replace the fuel filter and add fresh gas.

Precautionary Measures

  • Use eye protection: Depending on what you are doing, use proper safety equipment gloves and goggles are a must. The starter fluid can be nasty. In case of contact with your eyes, wash them quickly, and visit a doctor.
  • Work in a well-ventilated area: Try to perform this procedure in an open, well-ventilated location, as the starter fluid is extremely flammable and dangerous. Ensure that there are no flames or anything else that can ignite the fluid close. Also, be careful if the engine is hot.

Related questions

1. What else can you use as a starting fluid?

Premixed gasoline can be used as a starting fluid alternative. But if the gas is not premixed, it will dry out the cylinder wall and can lead to damage. WD-40 or carburetor cleaner can also be used, but their emissions are bad. In any situation, it is advised to use proper starter fluid as recommended by the manufacturer.

2. Can starter fluid be used on a diesel engine?

No. Diesel engines use a different method to ignite the fuel, and starter fluid can not be used for that type of engine. It can even lead to major damage to the engine.

3. How to adjust the lawnmower fuel intake?

The procedure for fuel adjustment is pretty easy and can be performed without any professional help. On the side of the carburetor, you will find an adjustment screw. Often there is a mark on what the default setting is. Start by turn the screw till it perfectly matches this level or mark. Then adjust it until you can see that the engine runs perfectly. Also, check when you ask for more power from the engine that it still works correctly.

Final Remarks

Starting problems is something that many gas mower owners will experience at some point. They will occur more often during the period when the lawnmower is used less often. Or when the machine is not maintained less frequently. But using starter fluid, you can often start the machine and further diagnose where the problem is. For an engine not starting correctly, mostly carburetor is the main reason. If your machine is older, it can well be that the carburetor should be cleaned, repaired, or rebuilt. It is a good idea to check the fuel adjustment as well. And if possible, check the valve condition and clean them now and then.

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