Why Won't My Lawn Mower Start Without Starter Fluid?

Stacy Randall
by Stacy Randall

Whether you dread mowing your lawn or love it, a faulty lawn mower makes cutting the grass a real pain. When your mower doesn’t start, starter fluid can help, but you shouldn’t need to use it all of the time.

If your lawn mower doesn’t start without using starter fluid, you could be dealing with old fuel, a bad spark plug, or a dirty carburetor. These possibilities are especially likely if your mower has been sitting dormant all winter long. The worst-case scenario is that your mower could be going bust.

If every time you use your mower you’re spraying the carburetor with starter fluid, something is wrong. Starter fluid is not part of a regular mowing routine.

Why Do You Need Starter Fluid for Your Lawn Mower?

Typically, you shouldn’t have to prime your mower more than three times for it to start.

If you haven’t used your mower in a while, or the engine is cold, starter fluid can help get your mower started.

Starter fluid is also a great tool to help you diagnose the problem when your mower does not start.

For example, if your mower starts when you use starter fluid, then dies quickly, this indicates a problem with fuel delivery. In this scenario, your carburetor is likely the issue, and either needs to be cleaned or replaced.

Do All Lawn Mowers Require Starter Fluid?

You do not (and should not) need starter fluid for every lawn mower. There are some lawn mowers in which you should never use starter fluid.

Using starter fluid in mowers with diesel engines can cause significant engine damage. You don’t use starter fluid on electric lawn mowers since starter fluid is for gas-powered engines.

Note: When using starter fluid on your lawn mower, make sure to use a fluid specifically designed for small engines.

How Often Is It Normal To Use Starter Fluid for Your Lawn Mower?

A regularly-used lawn mower should not need starter fluid. Using starter fluid once in a while to jump start a stubborn engine is okay. Occasional use is typical if it’s late in the fall season, or you haven’t used your mower in a while.

However, using starter fluid most of the time is a sign that something is amiss with your mower.

How Can I Tell Why My Lawn Mower Won’t Start?

If your lawn mower won’t start without starter fluid, your first step is to diagnose the problem. Your mower could have a dirty air filter, bad spark plug, a dirty carburetor, or it could just need fresh fuel.

The easiest thing to do is clean the air filter, drain the gas tank, and re-fill it with fresh fuel. If this doesn’t solve the problem, it’s time to move to plan B.

Tools You Will Need for the Job

  • Carburetor cleaner
  • Carburetor or carburetor inlet needle and seat (if you need to replace them)
  • Screwdriver
  • Adjustable wrench
  • White Vinegar (Optional)
  • Needle-nose pliers
  • C-clamp
  • Rags
  • Rubber gloves
  • Socket or ratchet set

Step 1

Check the spark plug to see if it is wet. If it is moist, clean the plug with carburetor cleaner to get rid of oily residue.

Step 2

If this doesn’t fix the problem, or the spark plug is dry, check the carburetor. If you notice corrosion (a chalky, white substance), this could indicate your carburetor is a goner.

You can try to disassemble the carburetor and boil the pieces in white vinegar for about 30 minutes. However, if this DIY method doesn’t work, be prepared to replace the carburetor.

Step 3

If there is no corrosion on the carburetor, clean the main jet with a carburetor cleaner according to your mower’s manual.

Step 4

Check to make sure nothing is clogging the fuel line. Check the inside of the tank for debris. Next, remove the fuel line at the carburetor to see if gas flows.

If there is no gas, remove the fuel line before the fuel filter inlet. If gas flows out, you likely need to replace the filter. If there is still no gas, then the fuel line is likely kinked, and you need to replace it.

Step 5

If gas is getting to the carburetor, the problem could be with the carburetor inlet needle and seat. Clamp the fuel line with a C-clamp and check the carburetor bowl for gas. If the bowl is empty, you need to replace the inlet needle and seat.

Step 6

If the engine is not getting any gas no matter what you try, then you need to replace the carburetor.

When Is It Time for a New Lawn Mower?

A bad spark plug, changing out old gas, and even cleaning or replacing a carburetor are all simple fixes. However, sometimes the problem with your mower can be beyond fixing. Or, if it is fixable, it may not be worth the cost to make the repairs.

If your mower has a cracked body or the shaft is bent, it’s time to decide if it makes more sense to repair or replace it. The answer to this question depends on a few things:

  • How old is your lawn mower? If your mower has been around the block, it might be worth it to spring for a new one. New mowers are much more efficient.
  • How expensive was your lawn mower? If your mower wasn’t super-pricey, the repairs could outweigh the cost of simply replacing it.
  • Have you been thinking about making a switch to a different style of mower? (from gas-powered to electric, from walk-behind to ride-on, etc.) If so, before you sink any more money into a mower you don’t want anymore, go ahead and replace it.

Related Questions

How long does a lawn mower usually last?

The average lifespan of a gas-powered lawn mower is roughly 7 to 10 years. With proper maintenance, you can extend the life of your mower. Change the air filter and the spark plug once a year and change the oil after about 25 hours of use. Add a fuel stabilizer at the end of mowing season or if you won’t be using your mower for a while. An electric mower can also last up to 10 years. However, the life expectancy of the battery is about five years. 

Should you get another gas-powered lawn mower or go with an electric model?

Whether you get a gas-powered mower or an electric lawn mower is a matter of personal preference. Electric lawn mowers are more eco-friendly and quieter than their gas-powered counterparts. However, gas-powered mowers are more powerful and are a better match for large lawns. 

Wrapping Up

Sometimes, a stubborn lawn mower engine might need a quick burst of starter fluid to help get it going. However, if your lawn mower won’t start without starter fluid, it could have a dirty air filter, bad spark plug, old fuel, or a dirty or busted carburetor.

Using starter fluid can help you diagnose the problem, but you shouldn’t always need starter fluid to get your mower to work. If after cleaning or replacing the gas, air and fuel filter, spark plug, and carburetor, the engine still doesn’t work, you might need a new mower.

Most of the time, if you keep reaching for starter fluid, the problem is an easy DIY fix. Plus, with proper maintenance, you can make sure that your lawn mower is always a cut above the rest!

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Stacy Randall
Stacy Randall

Stacy Randall is a wife, mother, and freelance writer from NOLA that has always had a love for DIY projects, home organization, and making spaces beautiful. Together with her husband, she has been spending the last several years lovingly renovating her grandparent's former home, making it their own and learning a lot about life along the way.

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