Briggs And Stratton Mower Won't Start After Sitting? (Try This Fix!)

Upgraded Home Team
by Upgraded Home Team

It’s summertime and that means dragging your trusty lawnmower out of the shed and of course, it won’t start. When it does start, it only does once and never again. Typical!

Your Briggs and Stratton lawnmower that has been sitting in your shed or garage may have numerous mechanical issues – ones that would prevent it from starting. There are many causes of this frustrating problem.

If your Briggs and Stratton lawnmower will not start after sitting, make sure you run a full check up of the engine. Begin by checking if it is out of gas, has a clogged air filter, or a faulty spark plug. Clean and maintain your carburetor as dirt and grime residue is often the source of the problem.

If you encounter this problem, don’t take it to the shop yet. Below are some information you need to get your mower started.

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Reasons Why Your Briggs And Stratton Lawnmower Won’t Start

Safety First

When working with a mower, keep in mind that gas or petrol is flammable. Therefore, ensure that all sources of ignition like stoves, sparks, cigarettes, and other hot objects are not in the vicinity. Also, allow adequate ventilation to prevent vapor buildup.

Also, it’s always a good idea to check your Briggs And Stratton mower’s user manual. This is to know how your mower should be positioned during oil changes, deck cleaning, and blade removal.

With that out of the way, here are the common causes why your mower won’t start and the potential fixes.

1. Out of Gas or Old Gas

Have you ever called customer support and their first instruction is to check if your electronic or machine is plugged in? It’s the same scenario with your lawnmower.

It sounds crazy but it’s likely your lawn mower won’t start because it has no juice. Thus, before you throw a fit, check your mower’s fuel level. Also, even if the tank has fuel, it might be old gas. Gas has a shelf life of 30 days due to ethanol. Plus, when the condensation inside the tank mixes with the gas, it waters down the fuel.

How to Fix

Check if your mower’s fuel tank is empty or not. If it’s been a while since the mower has been used (30 days ago or so), empty the gas tank and refill it with new fuel. Attempt to start the mower.

Alternatively, you can purchase ethanol-free gas to power your lawnmower. In general, ethanol-free fuel helps your outdoor equipment run more efficiently and you don’t have to worry about its shelf life.

2. Check and Change the Oil

For a lawnmower that has been sitting in storage for a while, it’s a must to check the oil. As a rule of thumb, it’s best to change the mower’s oil an hour after you finish mowing. However, if it’s coming off the storage, check the oil before you even start it.

Over time, the oil in your lawnmower can thicken. Check the oil if it’s good quality and doesn’t have residue in it. If the oil looks black or very dark, it’s time to change the oil.

How to Fix

When was the last time you changed the oil of your mower? If it has a while, just give your mower the much-needed oil change. Even if bad oil isn’t the primary cause of the mower not starting, it’s still likely a contributor.

Oil change for mower should be done at least twice a year. We recommend changing the oil before the mowing season begins and again before putting it away for storage.

For oil disposal, collect it with a bottle that caps tight. Then, visit your favorite local auto shop and they will happily recycle the oil for you.

3. Clogged Intake Filter

The intake filter sits on the intake side of the mower’s engine. This component filters the air that goes into the engine to mix with the fuel and combust. A clogged filter means that the engine is suffocated and combustion can’t happen.

A clogged intake filter may cause the engine to run briefly or not at all. One very telling sign of a clogged air filter is when the mower runs but suddenly stops during operation.

How to Fix

Instead of trying to clean the air filter, it’s highly recommended that you buy a replacement. The smallest hole or perforation in the filter gives dirt and residue a free pass to your engine. When left unattended, this can ruin your engine.

Fortunately, purchasing a mower air filter replacement is as easy as visiting your local Home Depot or Lowe’s. Expect to pay between $8-$10 for a new air filter. As routine maintenance, you should replace the filter annually.

4. Disconnected or Dirty Spark Plug

The spark plug is the component responsible for igniting the fuel and causing the engine to turn over. When your mower is in storage for a long time, the spark plug may have been corroded or clogged. A bad or dirty spark plug will cause the mower to not start at all.

The most obvious sign that you need a new spark plug is when the connected end has corrosion or discoloration. The business end should be the one with a small metal piece sticking out.

How to Fix

Replacing a mower’s spark plug isn’t complicated. You just need a spark plug socket wrench to remove the old plug and install the new one. Just be careful not to tighten the plug too much when installing the new one.

To purchase a new spark plug, simply head over to your local hardware store or browse Amazon. Briggs and Stratton parts are fairly popular so you shouldn’t have a hard time finding a spark plug for sale.

SAFETY WARNING: Whenever you’re working with the mower’s engine, always disconnect the spark plug. This is to prevent the engine from starting while you’re working on it. Simply unplug the black cable that runs through the end of the spark plug.

How to Prepare Your Briggs And Stratton Lawn Mower for Storage

To prevent your Briggs And Stratton Lawn Mower from not starting after sitting, you need to do some off-season tune-up steps.

Use a Gas Stabilizer

Many websites will tell you to drain the mower’s gas tank before storing it but that’s a costly mistake. We don’t recommend emptying the gas tank because it can harm the mower’s carburetor. It leaves your tank open to condensation which can trigger corrosion.

Instead, fill your tank with 95% full with fuel and gas stabilizer. Leave a little room so the fuel doesn’t expand and spill during warm weather. Avoid using gas that has ethanol as it can gunk up the carburetor.

Replace the Oil

The mower’s engine oil should be replaced at least once per season. Before the mower goes into storage, drain the old oil and replace it with a new one. Make sure that you use the oil recommended for your Briggs And Stratton mower.

Replace the Spark Plug

Even if the spark plug appears to be working fine, it needs to be replaced at least once every season. Over time, the spark plug’s performance will deteriorate because of carbon buildup. This ensures a smooth start for your unit when the mowing season comes.

Remove the Battery

To avoid a batter power drain, remove the mower’s battery before storage. Remove the battery and clean it with a cloth. For the cleaning of the battery terminal, use a metal brush or battery cleaner product. Store the battery in a cool, dry indoor location and away from things like the water heater, gas cans, and furnace.

Clean the Lawn Mower

Your mower has worked hard during summer so the least you can do is to clean it before putting it away. Brush or hose off grass, leaves, and mud from your mower. Before you do this, make sure you disconnect the spark plug for safety.

After the cleanup, store your mower in a dry, covered location like your shed, garage, or warehouse. It should be ready for springtime.

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Related Questions

What Type of Oil Should I Use for My Briggs And Stratton Mower?

Many DIYers change the oil of their mower on their own but many of them tend to use the wrong type. Indeed, it can be tricky especially when different oil types work best at certain temperatures.Fortunately, Briggs and Stratton have created an interactive oil finder that will help you quickly determine the oil type for your particular model.

Do I Need to Replace My Briggs and Straton Mower’s Blade?

Yes, otherwise you’ll be left with an ugly and unhealthy lawn. You have the choice to either sharpen or replace the blades. Now, this depends on your usage. A good rule of thumb is to replace your blades annually or if they get damaged. A sharp mowing blade can improve grass health.

Why Is My Briggs and Straton Lawn Mower Smoking?

If the smoke is black, there’s a good chance that it’s an engine problem. In this case, you should check the air filter after your Briggs and Straton mower cools down. On the other hand, white or blue smoke indicates that there might be an oil spill. You can solve this by restarting your mower and allowing the spilled oil to dissipate.

Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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