Lawn mower engine problems. Here s Why Your Lawn Mower Won t Start And What To Do About It

2nd August 2023

Here’s Why Your Lawn Mower Won’t Start And What To Do About It

Standing in your garage with a dead lawn mower, a phone browser open to Google, and the vast untamed landscape of small engine troubleshooting before you, it can be easy to get discouraged. After all, just about anything that prevents a lawn mower from running well can also prevent it from starting. Let’s simplify all these possibilities and zero in on common starting problems, and ones that you’re likely encountering.

Of course, your situation could include all manner of devices thought of as mowers. You could have a simple push mower, or maybe an electric start push mower. But, you could also have a riding mower, an electric mower, or a zero-turn mower that costs more than a Chevrolet Spark. You might even have a tractor towing a rotary cutter like a Bush Hog, in which case you’re probably not reading this article. We’re going to take a look at the most common: push mowers and riding mowers. Your electric mower is essentially always started, and your licensing agreement might prohibit your working on your own tractor. We also won’t deal with zero-turn mowers directly, but obviously a lot of the info for small engines in general will apply to zero-turns. Let’s dive into some of the reasons your mower may not be starting, and what you should do about it.

Ignition system problems: spark plugs

At some point — possibly when the words we have ignition from the Kennedy Space Center Firing Room — many of us began to think of the word ignition as synonymous with starting, but that’s not exactly what’s going on with ignition systems. An ignition system is actually about producing a spark that ignites a fuel-air mixture within an engine’s cylinder(s). Ignition happens continually when you’re using a mower. A few components of this system can be culprits when an engine won’t start.

The most common culprit is probably a spark plug that needs cleaning or replacement. Buildup from a constantly exploding engine cylinder will eventually degrade the performance of the plug until it can’t function properly at all. It’s a little easier to diagnose a bad spark plug in an engine that will barely start than one that won’t start at all, and if you’ve recently noticed that your mower makes you pull the starter rope harder, is prone to losing power while running, or starts using more gas than normal, the plug might be the problem. The clearest sign of plug trouble is when your engine will turn over but not actually start.

It’s a good idea to replace them at least once per year, and cleaning or replacing your plugs is a reasonable first step in resolving just about any starting problem. You can try gently cleaning a spark plug with fine-grit sandpaper, a file, or a soft wire brush, and you can use carburetor or plug cleaning spray to help. Just be gentle; damaged plugs will not be kind to your engine. There are other potential plug issues (wrong plug, bad gapping, or a cracked insulator) that might not be worth diagnosing, given that replacing the plug with a new (and correct) one addresses all these issues at once.

Ignition system problems: plug wires and coil

After dealing with the plug, it’s just about time to get serious with your diagnostics. But first, inspect your plug wires for obvious wear or damage. If they appear to be in poor shape, they probably are, which makes replacing them a good idea regardless of whether they are the full cause of your starting troubles. Next, it’s time to verify that your engine isn’t getting a spark. Ground your plug’s threads against a metal part of the engine itself and have someone attempt to start the mower as you observe the plug. If you consistently don’t see a spark, you should start looking at other possible causes.

If your plug wires are in good shape, ensure they’re making good contact with the spark plugs. Clean their terminals and, if necessary, squeeze the terminals slightly with pliers. If your mower has an on/off switch, use an electrical tester to make sure it’s functioning. Switches on mowers with pull cords can be slightly tricky to diagnose, so it might be a good idea to check the on/off function with a multimeter set to continuity mode. The point is that the continuity should change when the switch changes from on to off; some switches might close a circuit when on while others might open the circuit, but there should definitely be a change when the switch, well, switches. Check that the coil control wire connecting the engine to the coil isn’t abraded; if it shorts to the engine, the mower won’t start or run. Finally, consider replacing the coil. These are not user-serviceable, but they are affordable and critical to starting and running your mower.

Batteries die for a living

By far the most common element of the ignition system that can prevent a riding mower’s starting is the battery. Almost 20% — 11.8 million — of Google’s search results for the word battery include the phrase dead battery, because that’s what batteries fundamentally do: expend all their energy and die. And lawn mower batteries are almost always flooded lead acid batteries, which die more easily and more thoroughly than any other sort.

A lot of the work of fixing a battery problem is the same as properly maintaining the battery to begin with. That is, it’s stuff you should do regularly anyway. So, clean the battery terminals with a wire brush (clamp-on terminals might require a special type of brush, often cone-shaped). Use battery terminal cleaner if it’s necessary, though it rarely is. Make sure all electrical connections are clean and tight. Batteries that haven’t been maintained with a trickle or Smart charger while in storage, such as over the winter, will probably need to be charged and will sometimes even need to be replaced. If your battery is in good condition, check out your alternator and starter. Testing an alternator is simple on equipment with working headlights, as many riding mowers have. Just observe the lights. If they don’t dim when you turn off your engine, you probably have an alternator problem.

After verifying that you have a fully charged battery and a working alternator, check all the wires connected to the alternator and starter for damage. (You can test them with a multimeter if you’re suspicious of their condition.) If everything else checks out, test your solenoid and starter switch using the procedures outlined in this Briggs Stratton guide.

Fuel troubles

Every now and then you’ll see news about a possible perpetual motion machine devised in a scientist’s lab (or mind), but until you can pick one up at Home Depot, you’re going to be dealing with fuel for your lawn mower. This usually means gasoline, and there are a few common points of failure small engines can experience when trying to get fuel from the tank to where it’s needed for internal combustion.

First, make sure you have gas in the tank to begin with. This gets overlooked more often than you might guess, especially when you’re already half-expecting other mower problems and your brain primes the pump by framing everything in that context. Next, examine the age of the gas in use. Did you buy the mower used? Has it been in storage for more than a couple of months? Has the gas itself been sitting in the gas can for a while? Gas can go south in as little as a month, so if someone’s telling you it can sit for two years (a common number in mower lore) without chemical assistance or consequence, you should take your maintenance advice from someone else.

Mowers should be stored without gas or with an added fuel stabilizer (the aforementioned chemical assistance), to prevent such issues. Old gas clogs and damages fuel lines and carburetors, and won’t start an engine very well even if it makes it to the right place. If you already have old gas in your mower, you might need to remove and clean the fuel system components, as described here by Simple Green.

Fuel troubles: the fuel system

Replace your fuel filter regularly, especially if you’ve had old gas in your engine. If your engine has a fuel pump — and it probably does — it will reside between your fuel tank and the carburetor. When you’re out of options, check that it’s actually pumping by using a guide, like this one from Hello Practical.

There’s also the possibility that you aren’t availing yourself of some aids many lawn mowers have built into them to ensure the proper fuel/air mixture makes it to the engine. First, there’s the priming bulb: usually a clear, rubbery protrusion near the carburetor you can press. It will fill itself with fuel, injecting the fuel system with additional fuel as needed for starting.

You should also learn to use your engine’s manual choke feature properly, if it has one. Many newer engines have an automatic choke, and mowers generally have either a choke or a priming bulb, as they both perform the work of enriching the fuel/air mixture for starting your engine. Start your engine with the choke on, then move it to the opposite position once the mower is running properly. Leaving the choke on will stall or potentially damage the engine. Also, check to see if the tiny hole in your gas cap is clogged. That hole creates a vent to allow fuel to move down the fuel lines, and if it’s clogged, your engine will be starved of fuel.

Air filters

Of course, when it’s time for things to blow up inside your engine’s cylinders, gas is only half of the story. Your choke (if you have one) tells the other half: You also need air to mix with the gas, and some mechanisms to help with the mixing. The choke makes the fuel/air mixture richer by restricting (temporarily) the flow of air through the carburetor. Once the engine is running, you should return the choke (and, thereby, the airflow) to normal. But there are a few possible reasons you might continue to have airflow problems.

The first is a dirty air filter. Like most parts of a lawn mower, the air filter is prone to becoming filthier than seems possible. This means it’s doing its job, and it also means the filter requires cleaning or replacing from time to time. A dirty air filter will cause an engine to misbehave in all manner of ways, including not starting easily or at all. Your mower has one or two filters, any of which may be either foam or paper. It’s usually better to replace a paper filter if possible, but otherwise tap it against a hard surface and blow it out gently from the inside with an air compressor.

Foam filters are a bit more involved. Start by tapping and blowing it out like a paper filter, then spray it thoroughly with a filter degreaser and allow to soak for 15 minutes. Rinse under clean running water and allow it to dry, and then apply a filter oil spray. To the extent it’s possible without damaging the filter, squeeze the filter to work the oil throughout. After a few minutes, reinstall the filter and wipe away any excess oil.

air: carburetor

Sometimes your fuel/air mix is off because the carburetor isn’t doing its job properly. In extreme cases, this could prevent the engine from starting. At that point, you must choose between cleaning and rebuilding the carburetor. Fortunately, these processes are mostly very simple. The standard process for cleaning a carb is to remove and clean (or replace) the air filter, then inspect the carburetor inside and out for stray debris. Finally, spray carburetor cleaner into the carburetor while the engine is running, per directions on the spray can.

If this doesn’t work — perhaps because the gum and gunk inside the carburetor is extreme as a result of age or being run with old gasoline — removing and rebuilding the carb isn’t as scary as it sounds. It’s basically a process of taking the carb off and then cleaning everything off of it that you can. It’s also a good idea to take some photos along the way, so you can be sure of how everything goes back together. Finally, just reassemble. Briggs Stratton has a good online overview of this process.

If this makes you too nervous, try adding a cleaning mixture of 4 ounces Sea Foam Motor Treatment and 8 ounces gasoline to the tank. Remove the spark plug(s) and then prime and crank or rope-pull the engine to draw the mixture into the carb. Allow it to sit 24 to 72 hours, then run the engine per Sea Foam’s instructions.

Odds, ends, and tips

There are a few other fairly common situations that can interfere with starting a mower. It’s never a bad idea to change your oil, but be sure to do it properly. Old oil, insufficient oil, overfilling with oil, or using oil that’s the wrong weight (viscosity) for the temperature outside can all contribute to difficult starting.

Keep your mower deck clean; an overabundance of grime and debris can slow blade rotation and hinder starting. Similarly, if you’ve run into something recently with your mower, inspect the mower deck to make sure the blades can rotate freely. A blade striking the deck can prevent the mower from starting altogether.

Finally, there’s the unpleasant business of the starter rope — that thing you yank on a mower with a recoil starter. There are two types of mower owners: those who have cursed the fortunes and questioned the character of mower manufacturers for inventing the recoil starter, and those who haven’t used a recoil starter at all. Common causes of starter rope problems include overfilling with oil and debris interfering with rotation in the mower deck, as mentioned above. Similar problems include bent mower blades and damaged mower deck shrouds. The cord may also be difficult to pull because the flywheel brake (controlled by a bar you must hold while using the mower) is stuck. Try loosening or tightening the cable, then repeatedly open and close the bar that engages the flywheel brake. If this doesn’t work, you might need professional assistance. If you feel up to it, Briggs Stratton has flywheel brake replacement instructions. Similarly, a hydrolocked engine (one that has seized after getting water in the engine) will normally require professional help, unless you’re up for these steps from Garden Guides.

Problems that aren’t (exactly) problems

Sometimes you’ll hear that the cause of some problem is a feature and not a bug, but the distinction isn’t helpful if you can’t start your lawn mower. The best example of this is a mechanism called a safety interlock (or often safety switch), by which your mower won’t run because some other thing isn’t quite right. For example, riding mowers that won’t start unless you’re sitting in the seat. Some cars have interlocks that prevent you from operating them if you’ve had a few beers, but fortunately mowers don’t have this feature yet, as it would prevent about 90% of Saturday afternoon lawn mowing from happening at all.

The safety switches on most riding lawn mowers include a seat switch that will not allow the engine to run unless the seat is occupied; a PTO safety switch that might prevent the blades from turning in certain situations and prevent the mower from starting when (for example) the blades are engaged; a brake switch to keep the mower from starting unless the brake is applied; and a reverse switch, that prevents mowing. Obviously several of these can prevent an engine from starting if they malfunction.

It might be tempting to disable some or all of these safety switches. Don’t — they’re there for good reasons. Unless you’re handy with a multimeter and circuits, dealing with faulty safety switches might be another job for a professional.

Troubleshooting guide

So, how do you know which of these problems is preventing your mower from starting? Let’s look at a few questions that will help you narrow down the most common problems and their solutions. If your mower is full of fuel but only runs for a few seconds, check the pinhole vent in your gas cap for obstructions. This could also be a sign of old gasoline. If the engine hasn’t been run in more than a month, treat the gas as suspect. You might also clean the carburetor and clean or replace the spark plug(s).

If your engine sounds like it’s cranking, but won’t fully turn over, you might have an electrical problem — possibly the starter. If you hear a clicking sound but nothing else, that similarly suggests starter, battery, or related problems. If you don’t hear anything at all when you turn the key, check the starter solenoid and its connections. This also might indicate issues with the battery, coil(s), ignition switch, or safety interlocks. Hearing nothing at all could also indicate that your mower is refusing to start because it is low on oil.

If the engine is cranking slowly, you probably have a failing battery. Check the battery and alternator. If your pull cord is difficult to pull, check that the flywheel brake is disengaged. Be sure you don’t have too much oil in the engine, and that it’s the correct weight for the season. Another sign the engine might be overfilled with oil is the presence of blue or white smoke when it does run. Black smoke, on the other hand, indicates the fuel mixture is too rich. Replace the air filter and check the choke mechanism.

After a long winter’s rest, your mower may need a nudge before springing to life. Follow these simple steps for starting a lawn mower—and learn how to troubleshoot a mower that won’t run.

By Bob Vila and Tony Carrick | Updated Mar 24, 2023 12:54 PM

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Unless you’re planning to hire a lawn care company to handle your yard maintenance, you’ll need to learn how to start a lawn mower if you want to maintain a well-kept lawn. In addition to learning the basics, it’s also crucial to understand what factors influence how easy (or how difficult) it is to start a mower, including gas and oil levels and the condition of the spark plug and mower deck. The methods below will walk you through starting a lawn mower and help you troubleshoot any problems you may encounter along the way.

SUPPLIES

Below is the gear you might need to get your lawn mower up and running. It’s more than likely, however, that you won’t need more than a few items. The equipment you use will depend on whether there’s anything wrong with the mower, and the troubleshooting tips you follow below.

Before You Begin

Before starting up the mower, take a moment to walk your yard and clear it of any sticks, toys, and other obstacles that could damage your mower blade. Make sure that you have gas, oil, and other materials listed above close at hand.

Starting a Lawn Mower

Whether you’re new to lawn mowers, know how to use a lawn mower but have forgotten how to start one after a long off season, or are dealing with a mower that is refusing to start, these steps will help you get that mower up and running.

STEP 1: Check if your mower has gas and oil.

Look for the large black cap on the top of the mower engine (it should have an imprint of a gas tank on it). Unscrew the cap and peer inside to see if you need to add gas.

The cap for the oil pan will be on the opposite side of the engine. Look for an imprint of an oil can on the cap. Unlike the gas cap, which screws off, you should be able to remove the oil cap by giving it a half turn counterclockwise. You’ll know you have the right one when you pull the cap out and there’s a dipstick attached to it. Wipe the dipstick clean with a rag, replace it, then pull it out again and check the oil level. The oil level should be between the two marks on the stick.

STEP 2: Add gas and oil if needed.

If you’re adding gas, use the same unleaded gas you put in your car, and not the 2-stroke gas/oil mix that other yard equipment uses. Most push mowers hold between 1/4 and 2 gallons of gas. Use a funnel to avoid spilling the gas as you add it to the tank.

If you need to add oil, check the lawn mower’s user manual to see what oil weight the manufacturer suggests. If the manual does not specify an oil type, use SAE 30, the best option for engines that operate in warmer temperatures.

STEP 4: Prime the engine.

Priming the engine is necessary only if the lawn mower has not been used for a prolonged period of time (over the winter, for instance). Once you’ve attended to the mower’s gas and oil, press the primer button three to five times in order to channel gas into the engine. If you’ve used the mower recently, you can probably skip this step.

STEP 5: Pull the starter cord.

Notice how there are two handles on the lawn mower, each running horizontally only inches apart from the other. Press and hold these handles together, keeping them together as you pull the starter cord. Do so quickly and with considerable force, and the mower engine should to turn over. Sometimes it can take several attempts before pulling the starting rope achieves the intended result: a purring motor.

Troubleshooting Lawn Mower Issues

If you’ve already checked that the mower has ample oil and gas and it still won’t get up and running, it’s time to start troubleshooting. Here are the steps you should take to determine why your lawn mower won’t start:

Check the carburetor.

If you have already confirmed that there’s oil and gas in the mower, but the engine still refuses to start, it’s possible that either the carburetor has flooded or the cylinder has become soaked with gas. (The smell of unburned gas is a telltale sign.) Leave your mower on level ground for at least 15 minutes, which should allow enough time for the gas to evaporate from within the mechanism.

Check for old gas.

If you are starting your lawn mower for the first time after a long off-season in the garage, gas that was left in the machine may have gone bad. If you suspect this is the case, observe the mower the next time you try to get it going: Does it appear to start up, then quickly stall out? The fix is simple: Siphon the old gas and replace it with fresh fuel.

Check for spark plug problems.

While the spark plug’s location can vary depending on the mower, most of the time you’ll find it at the front of the engine. Pull the rubber cap off the spark plug. If you spot debris on the end of the spark plug or inside the cap, wipe it clean with a rag.

Unscrew the spark plug using a spark plug socket and socket wrench. Clean the electrode on the end of the spark plug with a wire brush and brake cleaner. If there are a lot of deposits built up on the spark plug or if it’s cracked, you’ll need to replace it with a new one. Otherwise, screw the spark plug back in, tighten it with the socket wrench, and attempt to start the engine.

Clean the grass clippings out of the mower deck.

Lay the lawn mower on its side so you can access its underside. Use a pry bar to dislodge any built-up clumps of grass from the mowing deck. After getting rid of the large pieces, use a garden hose to spray the deck. Give it a good scrub with a stiff bristle brush to remove stubborn debris sticking to the deck. Rinse with the hose, then turn the mower back upright and attempt to start it.

If you’ve tried these methods and your lawn mower still won’t come to life, refer to our detailed guide on what to do when your lawn mower won’t start.

Final Thoughts

While starting a lawn mower isn’t a complicated task, you can run into problems if the mower is low on gas or oil, has a bad spark plug, or if clumps of grass are clogging the mower deck and blade. The troubleshooting methods will help you learn how to turn on a lawn mower and get it back in action. In the event your best efforts to start the mower fail, there may be a larger issue with the lawn mower engine. In that case, you’ll need to seek out a lawn mower repair shop for help.

For more lawn mower advice, check out our video on the most common mowing mistakes almost everyone makes.

My mower won’t start

Starting problems with your lawn mower fall into 2 basic causes: fuel problems and ignition problems. The following is a simple checklist you can follow to help isolate a possible cause. This is not an exhaustive guide and certainly not a repair manual. However, there a few steps you can take before taking it to the repair shop for a thorough fix.

Fuel

This is the first and most obvious thing to check, especially if you weren’t having startup problems last year. Be sure that the machine has an ample supply of fresh fuel. It’s amazing how often people will get their mower out of cold storage the first warm day in spring and find their mower just won’t start. Forgetting that they left the fuel in the tank from the previous year. Today’s fuels don’t age well. In fact today’s gasoline is much like milk and starts to go bad quickly, often in as short a period as 60 days.

Ignition

Make sure that the ignition switch is on, that all attachments are disengaged and that the transmission is in neutral. Most machines have safety mechanisms that will not allow them to start otherwise. Consult your owner’s manual for the starting procedure for your machine.

Make sure the spark plug wire is firmly attached to the spark plug.

If it still doesn’t start, check for a spark by removing the spark plug and grounding the hex part of the spark plug to a bare metal part of the engine. Remove any spilled gasoline that is nearby first, then spin the engine by pulling the rope or turning the key. You should see a blue spark jump across the plug gap. If you have a good hot spark, skip to the carburetor section.

lf the spark is yellow and weak, or there is no spark then the first thing to do is try a new spark plug. Don’t try cleaning the old one. Set the new plug gap to the proper spec (usually 0.030) and check for spark again. If you do see a spark, install the new plug and try to start the machine.

If there’s still no spark, try cleaning and setting the points on older machines, or replacing the electronic ignition module on newer machines. Before replacing the old module test it by disconnecting all the wires from the module terminal that connect to the kill switches and recheck for spark, if you do see a spark then a wire or switch is probably defective. Also check the flywheel key. That affects the spark timing, usually the key will need replacing if you strike something while mowing and the engine stops.

Checking the carburetor and fuel system

If the fuel is fresh, you have a good spark and still won’t start, you must make sure that fresh gasoline is getting to the carburetor. Make sure that the fuel shutoff valve (if present) is opened, and that the fuel line is not plugged or kinked.

Also be sure the fuel cap vent is open and any screens in the tank are clear of debris. If fuel can flow to the carburetor, carefully place 1 teaspoon of gasoline down the spark plug hole (or a add shot of starting fluid into the carburetor throat). Re-tighten the plug and try to start the machine. If it runs for a second or two, then quits, chances are the carburetor needs to be serviced (disassembled and cleaned inspected, then rebuilt) or you have an air leak somewhere.

Lawn Mower Won’t Start. How to fix it in minutes, for free.

Make sure all mounting screws or bolts are snug and gaskets are not missing sections. If the carburetor is a bowl-type check for water in the bottom of the bowl (but do not let the float swing all the way down or the float needle will fall out!).

Hopefully, this will give you a little insight in what to look for if your mower won’t start. Most starting problems are fuel related because the previous year’s fuel wasn’t removed. You may have gone years without removing the fuel at the end of the year without having any starting problems. There is a chemical process called varnishing that puts a coating on the inside workings of your fuel system. Over time this process continually worsens until your system becomes inoperable.

Precautions

Gasoline can ignite very easily. Work only in well-ventilated areas and away from sources of heat, sparks, and flames. Always wear safety glasses, and be careful of sharp blades. Keep a fire extinguisher nearby.

Problems with Yamaha Lawn Mower Engine

Yamaha is a well-known brand in the engine industry. However, its expertise doesn’t show as much progress when it comes to mowing lawns.

Lawnmowers cut very uneven and thick grass which requires a higher level of energy emission. However, it’s best if you knew what are the possible problems with the engine of a Yamaha lawn mower.

Yamaha Lawn Mower Engine Troubles

You may be wondering why a well-known brand like Yamaha’s lawn mower motors would have problems. One of the biggest reasons is that Yamaha engines are designed for water activities rather than lawnmowers.

This is why most people face problems while using a Yamaha engine for mowing lawns. Yamaha motors are designed to last a long time and run smoothly, which is why they are often used in boats.

Yamaha engines, unlike lawnmower engines, are not designed to withstand extreme weather conditions. Lawnmowers are often left outdoors in the sun and rain, therefore their engines must be able to withstand these conditions.

Why do Yamaha Lawn Mower Engines Fail?

Yamaha motors are not designed to be used as lawn mower engines. Therefore they fail over time. Also, Yamaha motors are often less powerful than lawnmower motors.

Lawnmowers need a lot of power to cut through thick grass, and Yamaha motors may not be as strong as lawnmower motors.

Your Yamaha Lawn Mower Might not Start.

If your Yamaha lawn mower won’t start, it might be difficult to find out why, particularly if you’re unfamiliar with engines. The battery, a faulty spark plug, the fuel pump, and the air intake, are the most common causes of your Yamaha lawn mower engine not starting.

If a mower’s safety system is blocked, it may be difficult to start. Check the engine, and see if it’s working fine, if it needs fuel, or has some other issues. This can lead to an accident if you’re not careful.

The Yamaha Lawn Mower Starts Smoking.

If your Yamaha lawn mower engine starts smoking after running for some time then your Yamaha lawn mower engine may have issues. In this instance, the first thing you should do when the mower has cooled down, inspecting your Yamaha air filter.

If the Yamaha engine doesn’t get enough oxygen, it will get blocked. This might result in an abnormally rich combination of gasoline and air, causing Yamaha engines to operate badly and even emit smoke.

When the smoke issue persists, the oil seals in the engine’s lubrication system which causes this problem. Don’t try to do this on your own. Call a professional.

Your Yamaha Might Stop Working Suddenly.

People often complain that their Yamaha engine stops working suddenly while still cutting grass. This happens if the engine has internal problems. As said earlier, Yamaha engines are not made for lawn-mowing machines.

The kind of energy it takes to mow grass is much higher than what Yamaha has to offer. Bring in a professional to deal with the problem rather than doing it yourself because the chances of messing up things are huge.

The Solution to All Your Yamaha Lawn Mower Engine Problems:

You can solve your Yamaha lawn mower engine problems temporarily by restarting it. Here’s a guideline for you:

Lawnmower Won’t Start? Simple Method To Quickly Diagnose It!

For restarting the engine, first, ensure that the engine is switched on.
You’ll find an AC switch. The AC switch simply connects or disconnects electricity from the generator’s output to the necessary equipment. It’s not a switch to start the generator.
See if there’s sufficient oil in the engine. To maintain all of its engines in excellent working order, the Yamaha four-stroke generator incorporates an oil-warning system. When the oil level in the engine falls below a specific level, the oil-warning system immediately shuts off the engine, making it hard to restart. The engine can only be restarted if the oil level is at the proper level.
Consult the owner’s handbook to determine how much engine oil you need and what quantity of oil activates the oil-warning device. This information varies depending on the model.

Frequently Asked Questions (FAQs):

Why isn’t a Yamaha engine the right choice for lawn mowing?

Yamaha engines are not built for tasks like mowing.

How can I fix my Yamaha engine problems?

Engines problems aren’t silly home problems. It’s better not to do this on your own. Seek help from professionals.

Final Words:

If you own a Yamaha lawn mower engine, it’s better to make some adjustments as these engines aren’t really the ones you need in terms of mowing your lawn. Call a professional and get the problems solved.

If you think you can do this on your own, follow the manual thoroughly. If you’re considering buying a Yamaha engine for mowing your lawn, then you should reconsider.

So you are trying to get the lawn mowed, and your trusty mower won’t start?

How frustrating!

The lawn needs to be mowed, but the tool you need the most is not up to the task.

Good News! Most of the time a mower will start after some basic troubleshooting.

So what should you do next?

Here are a tips on some quick troubleshooting.

If you have a push mower this can be pretty simple.

Let’s take a look at the 5 steps you can take to get your mower up and running.

Start with the basics…. does it have gas in it?

Silly question, I know, but double check.

Time to check the air filter-

Take the air filter cover off, and remove the filter.

The air filter cover will be a plastic rectangle usually on the left or right side of the motor. Though, sometimes they are on the front. You may need a screwdriver to get the cover off, but most of the time they pop off easily, or have a fastener that can been removed by hand.

Now remove the filter, it could be stopped up with debris and this could be the problem, lightly tap the filter against a concrete surface to remove the debris, then use a vacuum cleaner to clean the rest of the debris.

While the filter is off try to start the mower quickly. Sometimes the filter gets covered in fuel, or is just too dirty for it to start.

Not recommending this, but in my experience have run a push mower for over a year with no air filter. I had to remove it to start the mower. Here’s the thing, the mower deck fell apart before the engine ever did.

IF the filter is torn, or your mower only starts when it is off you will need to replace. The Home Depot, Lowes, your local hardware or auto store should stock them. If you have time to wait, do a search online, enter the mower make and model into Google and you should be able to find it.

If you are having difficulty with the filter check out this lawn mower air filter guide.

Still nothing? Try Starter fluid.

Bad gas, clogged lines, and flooded motors are common issues for a mower not starting.

Now that you have cleaned the air filter, try spraying some starter fluid into the engine.

Behind the air filter there is a hole. Spray the starter fluid for 2-3 seconds into the hole behind where the filter sits. Then quickly try to start the mower.

It would be best if someone helped you pull on the starter cord repeatedly while you spray the fluid into the engine.

Most of the time this will get it started. Once you get it running, spray some of the carb cleaner into the carburetor while it’s running, this will clean the carb and prevent issues down the road.

Careful while you do this the blade is spinning!

Nothing again? Clean the carburetor and gas lines.

Water in the gas line, or just plain bad gas will prevent the mower from starting.

In most cases you can remove lower part of the carb by removing one bolt, which is located at the lowest part of the carb, see the photo below.

But first! You will need to drain the gas tank, assuming you have bad gas or water in the tank, you need to empty the entire tank.

Now that the gas has been removed, its time remove that bolt at the end of the gas line below the air filter. You can undo the bolt (see photo below) while the carb is still mounted on the mower. Keep in mind gas will come out. Once the bolt and reservoir are removed, flush the lines with good gas (safely and legally). Also clean the gas bowl with good gas.

Put it all back together, and fill it with good gas. Will it start now?If not, cleaning the entire carb takes longer, but may be necessary. Use this guide to do a complete carb cleaning.

By now I assume most of you are cutting your gas, but if none of that works….

It’s time to check the spark plug,

The spark plug will be on the front face of the engine and will have a rubber boot with a wire coming out of it that is connected to the tip of the spark plug. Make sure that rubber boot is connected properly.

Try starting again, if you still have no luck.

Most people don’t know this, but it’s time to remove the spark plug and replace it. You will need a spark plug wrench. If you don’t have one they can be purchased in the lawn and garden section of any major store, or at any auto parts store.

Remove the plug and take it to an auto parts store, and they will be able to match it up with the correct plug. Reinstall the new plug and try to fire it up again.

Sadly, if you are still here, then you could have more serious issue such as an internal motor problem or a bad carburetor.

Then it’s time to take it to a professional.

What’s the point?

If you have used these 5 Steps,

Check for gas
Check the air filter
Try starter fluid
Clean the carburetor
Change the spark plug

And it still won’t start you may need a new mower.

Here’s why, in most cases when it comes to a push mower it is not worth spending the money to have a professional repair it. A decent push mower can be bought for 200-500.

IF you drop it off at the lawn mower shop it’s going to be a minimum of 50 to look at it ,and before you know it you could possibly have a 200 repair bill in a mower that is not worth that.

I hope these tips helped out, and get you back running again.

Hi, I’m Gene Caballero and I’m the co-founder of GreenPal. At GreenPal, we’re helping hundreds of thousands of Americans solve one of the trickiest problems: a reliable, fast, and affordable way to get lawncare taken care of. On behalf of GreenPal, I’ve been featured in the Indianapolis Star. the Sacramento Bee. Entrepreneur. Inc.com. and dozens more. Please feel free to say hi on or connect with me on LinkedIn.

Sources:

https://www.housedigest.com/1206567/heres-why-your-lawn-mower-wont-start-and-what-to-do-about-it/
https://www.bobvila.com/articles/how-to-start-a-lawn-mower/
http://www.american-lawns.com/lawns/mower_startup.html
https://lawnask.com/yamaha-lawn-mower-engine-problems/
https://www.yourgreenpal.com/blog/what-is-wrong-with-my-mower

Lawn Mowers engine, lawn, mower, problems