Is your trusty lawn mower not starting like it should? That foul gasoline smell after tugging the cord likely means it has a flooded engine. Don’t worry – this common problem can often be quickly fixed with some simple troubleshooting. Here’s what you need to know about diagnosing, resolving and preventing flooded mower engines.

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Symptoms and Causes of a Flooded Lawn Mower Engine

Common Symptoms of a Flooded Engine

So you go to start up your trusty lawn mower after it’s been sitting idle all winter, yank the pull cord with eager anticipation of neatly trimmed grass, and…nothing happens. Or worse, instead of the satisfying vroom of an engine roaring to life, you hear an endless sputtering and smell the unmistakable stench of gas wafting through the air.

Unfortunately, these are telltale signs that your lawn mower engine has become flooded with fuel, which prevents ignition and makes starting it nearly impossible. But don’t despair—recognizing the common symptoms of a flooded engine can help diagnose the problem more quickly so you can get back to mowing your lawn sooner.

Engine Failing to Start or Turnover

The most obvious symptom that a small engine is flooded is when you pull the starter cord and the engine doesn’t start up. You may hear it trying to turnover with some sputtering noises, but it just won’t kick into action and properly run no matter how many times you yank the cord. This is often accompanied by the smell of gasoline, which is a dead giveaway that there is unburned fuel swamping the engine.

There are a few common causes for failure to start:

Overchoking – Leaving the choke on too long during starting will flood the carburetor and prevent ignition.
Overpriming – Pumping the primer bulb too many times when cold starting can overfill the carburetor with gas.
Old Gas – Gas that has been sitting in the tank and carb all winter can go stale, making it hard to ignite.
Dirty Air Filter – A clogged filter blocks airflow, causing sputtering and misfires.

So if your mower won’t start no matter how hard your pull, it likely means fuel is preventing the engine from sparking and turning over properly. Time to start looking at ways to dry it out!

Smell of Gasoline from Mower

As engine flooding prevents fuel from properly igniting, excessive amounts can leak through the combustion chamber and escape through the exhaust system. One of the most common lawn mower flooding symptoms is the pungent smell of gasoline emanating from the mower. This is often more noticeable after trying unsuccessfully to start the engine, which further saturates it with gas.

If you catch a strong whiff of gas while struggling to start your mower, there is almost certainly too much fuel present. This overwhelming odor should prompt you to stop cranking the engine until the flooding can be addressed. The smell means fuel vapors are present, which could potentially ignite if the engine kicks over. Better to be safe and deal with the fouled engine first!

Engine Sputtering But Not Firing Up

Has your lawn mower engine suddenly begun sputtering like a old car on its last legs when you try starting it up? Those weird coughing and popping noises, followed by the engine stalling out, are indicators it is flooded with gas.

You will usually observe this after pulling the starter cord, when you expect the mower to roar to life but instead hear it trying to turn over with great difficulty. The sputtering results from attempts at combustion being thwarted by excessive fuel.

Sometimes, the engine may fire briefly with loud backfires or diminutive eruptions before the sputtering returns and it stalls out again. Other times, it fails to start at all. Either way, unusual sputtering shows fuel is obstructing the proper ignition process.

Excessive White/Blue Smoke From Exhaust

When trying to diagnose lawn mower problems, keep an eye out for white or blue smoke pouring from the exhaust area. This is often accompanied by the smells of unburned gas and sounds of engine misfiring. The smoke results from gas vapors being burned up when the spark plug finally fires, indicating improper fuel delivery is occurring.

Excessive exhaust smoke on mower start up, especially if it persists for more than a few seconds, points to a probably flooded engine. The white smoke is usually more pronounced after the mower has been sitting for some time, since gas accumulates in the cylinder and overwhelms it when restarting. Taking steps to remove the excess gas will help reduce the alarming clouds billowing from your lawn mower tailpipe.

The Bottom Line

While symptoms can vary slightly depending on the model and make of your machine, failure to start, smelling gas fumes, sputtering noises, and puffing white smoke all signal that fuel is obstructing the engine from starting properly. Identifying these common indicators of a flooded mower can allow you to pinpoint the problem quickly and take corrective action to get back to mowing.

Pay attention as you attempt starting a lawn mower after storage and look for any signs it is choked with gas. Then review the recommended tips for clearing out the flooded engine to get your mower running smoothly again. With a few simple fixes, you can troubleshoot this finicky issue and enjoy a freshly cut lawn.

What Causes Lawn Mower Engines to Flood?

So you’ve identified the telltale signs that your lawn mower has an engine flooded with fuel. But what causes this pesky problem to happen in the first place? Understanding the root causes of flooding can help prevent it from occurring and keep your mower running smoothly. Here are some of the most common culprits behind fouled engines.

Over-Choking the Engine

The choke is a crucial tool for cold starting gasoline engines, reducing airflow so that a richer fuel mixture enters the carburetor. But leave the choke on too long, and you risk flooding the engine with gas.

Most lawn mowers require choking for only the first few ignition attempts. If the mower fails to start after 3-5 pulls with the choke engaged, it’s best to turn it off before trying again. Continuing to crank the motor with the choke on will overwhelm the carburetor with fuel.

Signs you may be over-choking:

Strong smell of gasoline while engine cranking
Engine sputtering but not turning over
Excessive exhaust smoke for longer than a few seconds

Follow your mower’s starting instructions to properly use the choke. And if it smells very gassy while pulling the cord, disengage the choke before trying again. Leaving it on too long is an easy way to foul your spark plug and pistons with unburned fuel.

Over-Priming the Carburetor

Most small engines require some priming before cold starting. This preps the carburetor with gasoline to aid ignition on the first pull. However, overdoing the priming can easily cause flooding issues.

The typical priming procedure is 3-5 pumps of the rubber primer bulb or throttle trigger. Excessive pumping beyond what’s recommended will overload the carburetor with gas. And since the fuel inlet needle gets stuck open from primer use, all that excess gas will keep flowing in.

Too much priming also increases the risk of engine kickback, as pressure builds in the combustion chamber. Err on the side of less priming, and only add more if needed. Overpriming before each attempt to start a stalled mower will compound flooding problems.

Using Old or Bad Gasoline

Gas that has been sitting in your mower’s fuel tank and carburetor over winter storage can go stale, causing starting and running issues come springtime. The performance of gasoline degrades over time due to oxidation, moisture buildup, and separation of additives.

Using old gas makes it harder for your engine to ignite the air-fuel mixture. Unburned fuel then builds up in the cylinder, eventually preventing starting altogether. This bad or stale fuel is a common root cause of lawn mower engines flooding after sitting idle for months.

For best performance, use gas less than 30 days old, and add fuel stabilizer to prevent degradation during storage. Drain the tank or add fresh gas if trying to start after prolonged sitting. Old gas is a frequent culprit behind flooded mower engines.

Dirty Air Filter Causing Restricted Airflow

The air filter is a critical engine component that prevents dirt and debris from entering the carburetor and cylinder. But over time, the filter can become clogged with dust, grass clippings and other gunk. This restricts airflow into the engine, affecting performance.

Limited air supply makes it harder for the engine to properly combust fuel, resulting in unburned gas fouling the plug and chamber. The reduced ventilation can make the engine more prone to flooding when choking or priming before starting.

Be sure to regularly check and replace dirty air filters to maintain full airflow. Use the recommended filter type for your mower. And don’t run the engine without any filter, as this accelerates carburetor clogging. Proper air filtration is key to prevent flooding issues.

When in Doubt, Let it Dry Out

Flooding can be caused by a variety of factors, but the underlying issue is always excessive fuel in the engine. If your mower exhibits flooding symptoms after you’ve followed proper starting procedures, let it rest for 15-20 minutes so any built up gas can dissipate. Taking a little time to dry out can often resolve many flooded engine causes without further intervention. But for recurring issues, address the root problem like bad gas, overchoking or dirty filters. With some troubleshooting, you can keep your lawn mower running smoothly all season long.

Dangers and Effects of Running a Flooded Engine

So you’ve determined your lawn mower has a flooded engine. Your first instinct may be to keep trying to get it started, yanking the pull cord again and again hoping it will eventually kick into action. However, running an engine flooded with gasoline can lead to further issues if not addressed. Here’s a look at some of the potential dangers and effects.

Engine Damage from Lack of Lubrication

One major risk of a flooded engine is potential damage from lack of proper lubrication. For an engine to run smoothly, fuel must combust and be surrounded by a thin film of oil for cooling and friction reduction.

Excess gasoline from flooding washes away and dilutes this critical oil film. Pistons, rings, cylinders and other internals start scraping against dry metal surfaces, causing accelerated wear. Parts expand and contract at different rates leading to additional strain.

Signs of damage:

Knocking or rattling noises
Power loss
Oil turning diluted and fuel-soaked

Running an engine in this state accelerates component wear and can lead to eventual engine failure. It’s best to refrain from continued cranking until flooding is resolved and proper lubrication restored.

Engine Stalling Leads to Inability to Mow

Even if you manage to get a flooded mower running, it will likely stall out quickly until the engine gets cleared of excess fuel. This results in an inability to properly mow your lawn, with the mower dying out every few minutes.

Attempting to mow with a flooded motor leads to frustration, uneven cuts, and potential damage from poor performance. And since the engine usually stalls with the blades engaged, it can be hazardous to restart.

It’s best to fully resolve the flooding first and mow later. Rushing into cutting grass before the engine normalizes leads to poor performance and risks. Take time to address the root issue instead of wrestling with a sputtering mower.

Gas Vapors Increase Fire Risk

Perhaps the greatest danger of a flooded engine is the heightened fire hazard from accumulated fuel vapors. Gas leaking into the cylinder has no way to burn off except the exhaust system, where it can ignite.

Running an engine in this state greatly increases the chances of an explosive backfire. Gas continues entering the chamber faster than the fouled plug can ignite, escalating the risk. Fuel-rich vapors through the exhaust can easily catch fire.

It’s critical to avoid sources of ignition until flooding is corrected. No smoking, sparking, etc. Attempting to mow wet grass before the engine has dried out multiplies the fire danger significantly. Address the symptoms before casually operating a flooded mower.

Let it Rest to Reduce Risks

A flooded lawn mower may seem like a quick fix, but attempting to push through the issue can cause bigger problems. Engine damage, poor performance, and fire risks accompany operating in a flooded state.

Rather than wrestling with a balky mower, allow time for excess gasoline to dissipate. Follow recommended steps to clear flooded engines, like air filter replacement and draining old gas. A little patience reduces the dangers substantially while improving performance. Don’t chance it—rest that flooded motor first!

Quick Fixes to Clear Out Flooded Lawn Mowers

Dealing with a flooded lawn mower engine can be frustrating, but often relatively quick and simple fixes can get it back up and running. Before resorting to taking your mower to the shop or complicated tear-downs, try some of these common troubleshooting tips to clear out excess gasoline and resolve the issue.

Letting Mower Sit to Evaporate Gas

One of the easiest methods to address a flooded mower is allowing time for the gasoline to dissipate on its own. Here are the steps:

Move mower to a flat, level surface. Tilting can cause gas to pool in one area rather than evaporating evenly.
Turn fuel valve to the off position to avoid any more gas entering the system.
Allow 15-20 minutes for the mower to sit undisturbed. This gives time for fuel vapors to evaporate from the carburetor, cylinders, and crankcase.
After time has passed, try starting again without choking. Often the rest period is enough to dissipate the flooding.

This simple fix of letting the mower sit avoids more invasive procedures. The wait allows fuel fumes to naturally clear without having to open the engine. Just be sure to avoid any ignitions sources nearby, as gas vapor will be present external to the engine as well.

Removing Spark Plug to Ventilate Chamber

Removing the spark plug is an easy way to help dry out the cylinder on flooded engines. Follow these steps:

Disconnect spark plug wire for safety.
Use spark plug socket or wrench to remove the plug.
Let plug sit for 1 minute to dissipate any gas buildup on electrode.
Dry off plug electrode with clean rag to remove excess fuel.
With plug still removed, pull starter cord several times to air out cylinder. This clears vapor from chamber.
Reinstall dried plug and reconnect wire when finished.

With the plug out, pulling the cord circulates fresh air through the cylinder to evaporate fuel rather than pumping more into a sealed chamber. The improved ventilation can help dry out the flooded engine. Just be careful not to create sparks near any escaping gas fumes.

Cleaning or Replacing Clogged Air Filter

A restricted air filter can contribute to flooding by limiting proper fuel combustion. Try cleaning or replacing the filter:

Locate filter housing and unhook any latches securing the cover.
Remove filter and check for heavy debris buildup blocking airflow.
For paper filters, gently tap and brush off external dirt. Replace if still clogged.
Foam filters can be washed in warm soapy water and dried completely.
Reinstall filter securely in housing, close cover, and latch.

Opening up the air flow by cleaning or replacing a dirty filter allows more air into the carburetor to correctly atomize the choke-enriched fuel on startup. Be sure to use the specified filter type and inspect regularly.

Replacing Old Gas with Fresh Fuel

If old gas is suspected, siphon it out and add new:

Disconnect fuel line from carburetor inlet and drain gas into an approved container.
Alternatively, remove fuel tank if possible and dump contents out.
Refill tank with fresh gas, preferably ethanol-free. Consider fuel stabilizer.
Reconnect fuel line to carburetor inlet.
Crank engine to allow new fuel into the carburetor bowls.

Old, degraded gas is harder to combust and can leave residue fouling the carburetor and cylinder. Fresh fuel can help resolve restart issues if bad gas is the suspected culprit. This may require running a few tanks of new fuel to fully clear out the old.

When to Take Further Action

If the quick fixes don’t address a persistent flooding problem, further troubleshooting or repair may be needed:

Disassemble and clean carburetor of residue if flooding recurs after fuel replacement.
Check for intake leaks allowing unmetered air to enter engine.
Inspect primer bulb and fuel inlet needle for defects allowing excess fuel.
Test spark plug and replace if found faulty or significantly worn.
Check compression to identify potential internal mechanical issues.

While many flood-related issues can be resolved with simple fixes, recurring problems likely indicate a larger underlying issue needing professional diagnosis. But start with the quick tips first before diving into major repairs.

Here is an 1800 word section providing a step-by-step guide to starting a flooded lawn mower engine:

Step-by-Step Guide to Starting a Flooded Mower

Follow this complete troubleshooting guide to get a flooded lawn mower running again. We’ll outline steps from letting it rest, verifying components, drying out fuel, and getting it started with best practices to avoid re-flooding.

Step 1 – Wait 15 Minutes Before Trying to Restart

Before doing anything else, allow a flooded mower to sit untouched for 15-20 minutes. This gives time for excess gasoline in the engine to dissipate and evaporate without pumping in more fuel.

Move the mower to a flat, level surface. This allows fuel to evenly drain rather than pooling.
Turn the fuel valve to OFF to prevent more gas entering system.
Let mower sit for 15-20 minutes undisturbed. Avoid priming or choking during this time.
After time has passed, try starting with fuel valve on and choke disengaged.

Often, just allowing time for the engine to dry out is enough to resolve a flooding issue and get it started again. Be patient and refrain from repeatedly cranking the starter, which will worsen flooding.

Step 2 – Check Air Filter Condition and Replace If Needed

Before attempting to restart, check the air filter and replace if it appears overly dirty or clogged:

Locate the air filter housing on the engine. It’s usually a plastic case with a cover that can be unlatched.
Remove the cover and take out the air filter inside. Visually inspect condition.
For paper filters, look for heavy buildup of debris that could restrict airflow. Try gently tapping filter to dislodge dirt.
Foam filters can be rinsed with warm water and dried completely before reinstalling.
Replace filter if still heavily contaminated even after cleaning. Use the specified replacement for your mower model.
Reinstall filter correctly in housing and close cover, engaging any latches.

Having a clean, unclogged air filter allows proper airflow into the engine to help avoid re-flooding.

Step 3 – Remove and Dry Out Spark Plug

The spark plug is key to combusting fuel in the cylinder. Removing and cleaning it can help dry out a flooded engine:

Disconnect the spark plug wire for safety before proceeding.
Use the proper spark plug socket or wrench to remove the plug from the cylinder head.
Let the plug sit for about 1 minute to allow gas buildup on the electrode to dissipate.
Clean the electrode tip using a rag or brush to remove excess fuel fouling it.
With plug still removed, pull the mower’s starter cord several times. This will pump fresh air through the cylinder to help evaporate gas inside.
When finished drying, carefully reinstall the cleaned plug and reconnect the spark plug wire.

The open cylinder allows air circulation to remove fuel vapors when pulling the starter cord. Avoid any ignition sources near potential gas fumes escaping the open socket.

Step 4 – Disengage Choke Before Attempting to Start

A common flooding culprit is leaving the choke on too long when trying to start. Remember to turn it off before pulling:

Consult your mower’s starting instructions for proper choke use. Most specify 3-5 pulls with it on.
If mower fails to start after several attempts with choke engaged, turn the choke lever or knob to the OFF position before trying again.
Without choke, pull the starter cord again. It should be easier to start with the enriched fuel mixture shut off.
If it starts, let it fully warm up before engaging the choke again. Use choke only when cold starting, not on a warm or flooded engine.

Be sure you’re not over-choking the engine. Turn it off promptly once the mower is close to starting.

Step 5 – Spray Starter Fluid if Needed

If the flooded engine still won’t start, starter fluid spray can help in a pinch:

Use caution and avoid open flames, as starter fluid is highly flammable. Spray away from ignition sources.
Remove the air filter assembly so the intake port is accessible.
Insert the straw from the starter fluid can into the open intake.
Spray a 1-second burst into the intake while someone pulls the starter cord.
The quick fuel ignition may help kick over the engine. However, it will billow white smoke until fuel clears.
Immediately reinstall air filter after using. Starter fluid is only a temporary crutch to start flooded mowers.

The quick-burning fluid ignites easily when the plug fires to start the engine turning over. Use sparingly to avoid engine damage.

Step 6 – Crank Engine Without Air Filter to Clear Gas

If previous steps fail, removing the air filter while cranking can help purge flooded fuel:

Remove the air filter assembly from the engine as done previously.
With filter detached fully, pull the starter cord several times to turn engine over.
This will allow air to flow through the intake and help evaporate gas puddling in the cylinder and carburetor.
Listen for changes while cranking – if the engine tries to turn over, flooding is being cleared.
Replace air filter once fuel appears dissipated and mower starts. Run briefly to stabilize.
If mower starts with filter off but stalls once reinstalled, the filter needs replacement due to excessive clogging.

Run the engine without filter just long enough to clear the flooding. Avoid dust ingestion by limiting cord pulls.

Let it Cool Down if Needed

If the mower still fails to start after working through these steps, wait an additional 15 minutes before trying again. This allows things to fully cool down and restarting on a blank slate. Rushing through the process often just causes repeated flooding. Slow down, verify components, and methodically dry out the engine before reattempting start. Patience and diligence will pay off with a smoothly running machine.

Following this complete sequence engages the various remedies step-by-step to systematically fix a flooded mower. Don’t skip any actions, as each prepares for the next. With time and care, your lawn mower will be chugging along again in no time.

Preventing Lawn Mower Flooding During Storage

Proper storage steps can go a long way towards avoiding starting issues due to flooding when you take your mower out for the new season. Here are some key tips to maintain your equipment and prevent fuel-related problems after sitting idle.

Run Mower Dry Before Storing

Before packing up the mower for winter, run the engine until it uses up remaining fuel and stalls out naturally:

Mow lawn fully until you empty the current tank of gas. Use a fuel stabilizer additive.
With tank empty, start engine and let it run at mid throttle until stopping on its own as remaining fuel depletes.
This avoids leaving fuel sitting in the carburetor and intake over the off-season. Any remnants will evaporate.
Drain oil after running dry, before it absorbs gas fumes. Refill with fresh oil before next use.

Letting it sputter to a halt burns excess fuel rather than leaving it to gum up and cause issues later. Be sure to monitor closely to avoid damage from running dry.

Stabilize Fuel or Drain Tank & Carburetor

To avoid degraded gasoline causing problems:

Add fuel stabilizer to a full tank and run for 10+ minutes before storing to circulate.
Drain tank & carburetor fully and dispose of old gas responsibly if stabilizer not used.
Cover inlet hose end with plastic wrap after disconnecting to contain drips.
Stabilizer treats fuel over months while drained components start fresh next season.

Stale gasoline left over winter is a prime contributor to flooding and hard starts come spring. Manage it carefully when storing equipment.

Change Oil and Clean Air Filter

Two other key maintenance steps before storage:

Change engine oil and filter to remove built-up combustion contaminants. Used oil attracts moisture.
Remove air filter and tap off debris. Replace if excessively dirty. Restricted airflow causes issues.
Clean exterior buildup and remove grass clippings with compressed air.
Apply fresh oil on any moving metal component and wipe down exterior. Protects against corrosion.

Fresh fluids and filters ensure optimal performance next use. Don’t defer maintenance when storing your mower.

Store Mower Indoors in Dry Location

Protect your equipment by:

Storing mower inside a shed or garage away from elements if possible.
Avoid setting directly on concrete, which can promote rust. Use wood blocks.
Cover with vented tarp to protect from dust if storing outside. Avoid plastic tarps which promote condensation.
Maintain storage temperatures above freezing to inhibit fuel gelation and moisture issues.
Avoid areas with high humidity, as moisture causes corrosion during inactivity.

Proper storage conditions reduce deterioration of components and keep fuel systems primed for easy starts next season.

Remove Spark Plug Before Long-Term Storage

For mowers stored 6+ months:

Remove spark plug and pour ~1 teaspoon of oil into cylinder hole. Replace plug.
Crank engine to distribute oil evenly to prevent cylinder rusting.
The film of fresh oil protects internals from corrosion and moisture damage during prolonged storage.
Combine with other steps like fuel treatments, oil changes, stabilizer, etc.

The protective oil layer is cheap engine insurance when equipment sits unused for an extended period.

Applying these best practices for storing your mower over the off-season will help minimize fuel-related problems when you go to start it up again. Maintaining fresh fluids, running it dry, stabilizing gasoline, and proper storage conditions give your equipment the best shot at easy ignition after sitting. Follow the checklist to sidestep frustrations from flooding issues.

When to Call a Mechanic for Flooded Lawn Mower Issues

While many cases of lawn mower flooding can be addressed with some DIY troubleshooting, more persistent or complex issues may require professional service. Here are some signs it’s time to take your flooded mower to the shop:

If Flooding Persists After Attempted Fixes

If you’ve tried the standard fixes like:

Letting the mower sit to dry out
Cleaning or replacing the air filter
Checking the spark plug
Using fresh gas

And the engine keeps getting flooded and is difficult to start, there may be a more serious underlying problem. Further investigation by a small engine pro may be needed.

Recurring ignition issues that aren’t resolved by common troubleshooting likely indicate an issue like:

Defective or dirty carburetor
Damaged fuel pump or clogged pickup
intake system leaks causing unmetered air flow
Compression problems from worn piston rings or cylinders

A technician can diagnose and service these types of stubborn flooding causes. Don’t continually struggle with a temperamental mower.

For Engine Repairs Needed from Flooding Damage

If flooding issues persist for too long before being addressed, engine damage can occur, including:

Scoring of cylinder walls from insufficient lubrication
Stuck or damaged piston rings
Overheating from abnormal combustion
Fouled spark plug electrodes

These conditions can lead to significant power loss, oil burning, excessive smoke, and reduced engine life. The repairs needed may be outside the scope of the average DIYer.

A pro can overhaul the engine properly if significant wear or scoring is present. This may involve cylinder boring, piston replacement, gasket repairs and more.

Don’t keep running an engine that has sustained damage from flooding issues. Seek professional help to get it back in shape.

To Diagnose and Fix Root Cause of Recurring Issues

If flooding keeps coming back no matter what you try, there is likely an underlying issue that needs resolution, such as:

Faulty float or inlet needle allowing excess fuel into carburetor
Damaged fuel pump or clogged pickup preventing proper fuel delivery
Vacuum leak drawing in unmetered air
Improperly seated valve or worn valve seat causing compression loss

Repeated flooding suggests something is wrong at a fundamental level, beyond just getting the engine temporarily started.

Seeking professional help can identify the true root cause so it can be repaired and avoid repeated problems in the future. Don’t just treat the symptoms only to have issues resurface again and again.

Getting to the bottom of recalcitrant mower problems requires experience. Seek out a trusted small engine repair shop that can diagnose and fix the real issue for good. Your patience and grass will thank you!

Key Takeaways on Flooded Lawn Mower Engines

Dealing with a flooded lawn mower engine can be frustrating, but armed with the right knowledge you can get your mower running again quickly. Here are the key takeaways:

Common symptoms of flooding include failure to start, gas smell, engine sputtering, and white smoke from exhaust. Be alert for these signs.
Over-choking, over-priming, old gas, and dirty air filters are common causes of fouled engines.
Letting the mower sit 15-20 minutes allows fuel to evaporate before attempting to restart.
Check basic components like the air filter, spark plug, and old gas. Replace or clean as needed.
Removing the spark plug and drying the electrode can help clear flooded chambers when cranking the starter.
Always turn the choke off once the mower is close to starting to avoid re-flooding.
If needed, use starter fluid spray and run without air filter briefly to start severely flooded mowers.
Prevent issues by storing properly with stabilized gas, an oil change, and running the carb dry before off-season.
Seek professional help if flooding persists after trying basic fixes. Damage or underlying issues may need repair.

Keep these flooded engine troubleshooting tips handy so you can get your mower running smoothly. With quick action, you can often avoid extended downtime and expensive repairs from flooding.

Frequently Asked Questions About Flooded Lawn Mowers

Q: Why does my lawn mower keep flooding?

A: Repeated flooding is typically caused by an underlying issue like a faulty carburetor, deteriorated fuel lines, malfunctioning fuel pump, intake leaks, or worn engine seals. Have a small engine pro diagnose and repair.

Q: Is it safe to start a flooded lawn mower?

A: It’s not recommended. Flooded engines have a higher risk of kickback, fire from fuel vapors, and mechanical damage. Allow time to dry and dissipate gas before starting.

Q: How do I start a lawn mower with a flooded engine?

A: Let it sit 15-20 minutes, remove/dry the spark plug, replace air filter if clogged, use fresh gas, start with choke off, and crank with starter fluid or no filter to clear excess fuel.

Q: What happens if you keep trying to start a flooded mower?

A: Continually trying to start a flooded engine without addressing the root issue can cause engine damage from lack of lubrication, stall the mower, and increase fire risks.

Q: How can I prevent my mower from flooding?

A: Use proper starting technique, maintain fresh fuel, clean the air filter regularly, fix any intake leaks causing unmetered air, and store properly with stabilized gas and by running the carburetor dry.

Q: Does putting oil in a flooded engine help?

A: No, adding oil to a flooded engine will not help resolve the root issue. The problem is too much fuel, not a lack of oil. Allowing time to dry and evaporating excess gas is needed.

Q: How do I dry a flooded mower engine fast?

A: Removing the spark plug while cranking the starter and spraying starter fluid into the carburetor can help dry out a flooded engine more quickly. But time and air circulation are best.