Fixing a Hard-Starting Lawn Mower

Whether it’s the first mow of the season or the last mow before storage, it’s frustrating when your lawn mower is hard to start or won’t start at all. The good news is that most of the time, lawn mower problems are the result of dirty components or poor fuel storage; sometimes both.

Luckily, these problems are usually simple to fix and can be taken care of at home with a few common tools and a little bit of time. Let’s take a look at some of the primary culprits that could keep your mower from starting and how to fix them.

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DIY Lawn Mower Maintenance

To fix most mowers that start hard or won’t start, you’ll first need to gather a few things: a Phillips-head or standard screwdriver, spark plug wrench (usually ⅝”), a socket set, Sea Foam Spray, Sea Foam Motor Treatment, and a container to catch fuel. Then it’s time to get started.  

Clean or replace your spark plug

Spark plugs in gas lawn mowers wear out, just like those in your vehicle’s engine. To locate your spark plug, check your owner’s manual. Once you’ve located your spark plug, remove the rubber boot and take the plug out using a spark plug wrench or socket.

If the electrode end of the spark plug is dark with carbon deposits, you can give it a good clean with a soft wire brush and Sea Foam Spray. If your plug won’t come clean or appears damaged, it’s best to replace it. If replacing, be sure to get the plug recommended in your owner’s manual and gap it correctly.

Clean or replace your air filter

The air filter housing is typically on the side of your mower and will be flat and shaped like a square or rectangle. It can usually be easily removed using a screwdriver. Once you get into the housing, check the condition of your air filter. Most foam filters can be gently washed with dish soap and water. Be sure to let it dry thoroughly before reinstalling. A paper air filter can often be vacuumed or sprayed with an air hose. If the air filter is too dirty or damaged, replace it.

Clean your carburetor

When fuel sits for a long time, it deteriorates and can gum up your carburetor with sticky varnish deposits, causing tiny passageways to clog. When this happens, your engine can’t get the appropriate air/fuel mixture, resulting in hard starts, rough idle or no start at all.

If your engine starts, but runs rough, or if it’s starting hard, you can try cleaning your carburetor by adding Sea Foam Motor Treatment to your fuel and running Sea Foam Spray through your intake as shown in this video.

If your mower is not starting, you may have to remove your carburetor, clean it and reinstall it, or replace it entirely. This is a simple job for a small engine technician, but is also a DIY project if you have a little patience and a few tools. Though they all operate the same, carburetors differ by manufacturer, so you’ll want to consult a service manual for your model for proper disassembly.

Most importantly, you’ll want to make sure that the float bowl and primary jet are clean. You can do this with Sea Foam Spray and a soft wire brush.

Clean Fuel is Key

The main way to prevent a mower from developing starting issues is to develop good fuel practices. Use fresh gas — no more than a month old — whenever possible. Also, adding fuel treatment, like Seam Foam Motor Treatment, will help stabilize and optimize your fuel’s performance. Sea Foam Motor Treatment can be used to stabilize fuel for up to two years, making it ideal for storing seasonal equipment.

SEA FOAM MOTOR TREATMENT can help keep your lawn mower starting like new.

SEA FOAM CAN HELP
Sea Foam Motor Treatment works to clean injectors and restore factory spray patterns. It is safe and effective for all types of gasoline fuel injection systems. Using Sea Foam Motor Treatment in your gas is also a good way to ensure all components of your fuel system stay clean and perform their best.