A well-maintained and green lawn increases the aesthetics and value of your home. Thus, maintaining the lawn is of great importance. Thankfully, a lawnmower comes in handy to cut, slash and trim the grasses on the lawn to make it look good.

Nonetheless, it can be problematic when the lawnmower doesn't perform well or shows signs of malfunctioning. One such problem happens when the lawnmower only starts with starting fluid. Although starting fluid is useful to run the machine, when you need it always, it isn't a good idea.

It happens due to old fuel, dirty carburetor, and bad spark plug. Also, if you see the lawnmower clicks but won’t start, it might be because you have kept the machine idle during the entire wintertime.

Although it can be worrisome, you can solve it with a few easy steps. So, we will show you why the engine only starts with starting fluid of your lawnmower and its solutions.

Why The Lawnmower Only Starts With Starting Fluid:

The lawnmower has a small engine inside it. And like all smaller engines, when it starts only to die after a few moments without the starter fluid, it is linked with the improper fuel supply. Unfortunately, many people get worried when their machine fails to continue running. Thus they will ask, "Why my lawnmower only starts with starter fluid?"

So, here are the top reasons for an engine not working without the starting fluid. Once you know these reasons, you may fix them with ease.

Trouble in the carburetor:

Although you may not like it, the most common reason for a malfunctioning engine is the carburetor. When the component fails to supply a proper mix of fuel and air to the engine, the machine will face hiccups and shut off abruptly.

Mostly when the carburetor gets dirty, this problem starts happening frequently. The dirt inside the carburetor will disallow the component to mix fuel and air in the right ratio. When you keep the mower in an idle state for months, the carburetor gets dirty and causes the machine not to run properly.

When the machine sits idle for months, and there is fuel inside the carburetor bowl, the fuel will slowly develop a layer there. The layer looks like varnish build-up and stops the carburetor from supplying the proper ratio of fuel and air due to the gums around it.

Old fuel:

Using old fuel is never a good idea for the health of engines. The same goes for lawnmowers. Just imagine the condition of how much havoc a little amount of fuel can do to the carburetor when kept inside the bowl without use.

So, how much damage can unused and old fuel do directly to the engine? Also, you can never tell when the fuel or gas of the lawnmower engine goes bad. Nonetheless, experts say that when you keep the machine idle for months with gas inside it, it doesn't take long for the fuel to go bad.

Usually, premium gas and non-oxygenated gas fuel last longer. Also, you may add a fuel stabilizer with the gas to increase its lifespan before it goes bad.

Air filter gets clogged:

An air filter works to filter the air so that the engine receives pure air without residues and dust in it. When the air filter gets clogged, its performance drops. So, it won’t let as much air to let go inside the setup as the engine requires.

When the air filter stops the required amount of air from going inside the setup that the engine needs to run, the lawnmower will fail frequently. Usually, when you tilt the lawnmower to clean it, oil might leak and clog the air filter. So, the engine won't get the required air to run properly.

Consequently, you will see that the lawnmower clicks but won’t start.

Issues with the spark plug:

When you see that the engine only starts with starting fluid, it also could be due to the bad spark plug. When you check that the issue is not with the air filter or carburetor, it could be a damaged or bad spark plug.

Also, if the lawnmower won't restart when hot, it mainly happens due to the spark plug. Thankfully, you can easily detect the problems with the spark plug and replace it.

Inappropriate oil level:

When everything is in good condition, and still the lawnmower won't start without starting fluid, you must check the oil level. In reality, putting too much oil in the engine can drop its performance. Also, putting too much oil in the engine will bog down it. Consequently, the engine will die.

Thus, you must keep the oil level of the lawnmower at the recommended level.

Solutions for Lawnmower Starts With Starting Fluid Only

We have already mentioned why your lawnmower engine is not running without starter fluid. As you have diagnosed the problem, it's time to fix it.

Clean the engine carburetor:

It would help if you cleaned off the carburetor using a commercial cleaner. Also, get one with a thin straw as it helps you spray the cleaner right where you want it to be. Once you have opened the can, apply the cleaner to the air intake of the carburetor.

If applying the carburetor cleaner through the air intake doesn't help, you will need to disassemble the entire carburetor and clean it manually.

Change the air filter:

When the lawnmower running issue is due to the air filter, you must swap it. Firstly, check the air filter and find how much dirt or oil is inside it. In many cases, you might remove the residues and fuel from the air filter to help it work properly.

However, if it has become too dirty, you might need to replace it. You can follow the user manual of the lawnmower to replace the old air filter with ease. Or you will get videos on YouTube to know how to replace a lawn mower air filter.

Remove old oil and use a new oil:

When you plan to start the lawnmower after a long time, you should drain its old fuel entirely. Also, clean off the fuel and carburetor before starting the lawnmower.

You may also check the color and smell of the fuel to know if it has gone bad. Usually, the gas that has gone bad will have a pungent smell. Also, the gas will turn a dark or deep amber color which signals that it has gone bad. Thus, you must drain the fuel and fill the engine with new gas. You should use premium gas to boost the performance of the lawnmower.

Changing the spark plug:

You will need to remove the wiring of the spark plug first. Then, unscrew it using the deep socket. You may alternatively use a spark plug wrench. Check the spark plug electrode and see if it has become too dirty or damaged.

If the electrode isn't damaged and isn't too dirty either, you can clean it off and then attach it to the engine. Nonetheless, experts suggest that you should replace the spark plug once every season since it's not so expensive at all.

Adjusting the oil level:

Finally, you have to adjust the oil level of the lawnmower engine. For this, check the engine's oil level and adjust it accordingly. We suggest you maintain the oil level as the user manual recommends. It will also increase the performance of the lawnmower.

How to Use Starter Fluid on Riding Lawn Mower

You will need to apply the starter fluid to the lawnmower's carburetor. Using the sprayer straw, you will need to spray the starting fluid directly on the carburetor. However, keep the machine idle while you spray the fluid. After that, run it for a few moments to help the fluid get mixed properly.


You shouldn't get panicked if you see the lawnmower only starts with starting fluid. It doesn't mean that the machine has gone bad. The problem could be with the dirty carburetor, air filter, inappropriate oil level, and bad fuel. So, diagnose the problem thoroughly and fix the component of the lawnmower. The DIY lawnmower fixing project will be great fun.