Four stroke lawn mower. How do I Know if my Lawnmower is 2 or 4-Stroke

How do I Know if my Lawnmower is 2 or 4-Stroke?

You just bought a new lawnmower and you are happy about it. You are eager to mow your lawn for the first time but there is no gas in the gas tank.

You are not sure the fuel you have is the right kind of fuel for the engine. First, you have to find out the kind of engine in the mower, to know the kind of fuel you require.

One of the questions you should ask is, how do I know if my lawnmower is 2 or 4-Stroke? If you can answer this question, you can handle the mower without hassle.

How do I know if my lawnmower is 2 or 4-stroke? If this is the challenge you are facing, do not worry.

In this article, you will learn everything you are supposed to know about 2-stroke and 4-stroke engines. You will learn how to differentiate between the two.

How do I know if my lawnmower is 2 or 4-stroke?

Many lawnmowers are 2-stroke engines. Nowadays, people are going for 4-stroke engine lawnmowers because of their environmental friendliness.

If you check the fuel tank of your lawnmower, you will know the type of engine it has. 2-stroke engines have one port for oil and gas. 4-stroke engines have two ports for oil and gas. You will learn more of this in the article.

How to Check the Type of Engine:

Fuelling is the major difference between 2-stroke and 4-stroke engines. Check your lawn mower’s fuel tank. If it has just an intake port, know it is a 2-stroke engine. You have to mix oil and gas, that is the reason it has just a port.

When it comes to 4-stroke engines, you will see two different ports. One is for oil and the other is for gas. Therefore, an examination of your lawn mower’s fuel tank tells you if it is a 2-stroke engine or a 4-stroke engine.

Another way you can differentiate the two is their noise. 2-stroke engines produce thunderous noise. The noise produced by the 4-stroke engine is normal and bearable.

Check the quantity of smoke your lawnmower exhaust emits. 2-stroke engines emit much smoke while the smoke emission of the 4-stroke engine is low.

There must be fuel in your lawnmower for you to apply this method. Your lawnmower should be running well too. Where there is no fuel in your lawn mower’s tank, you have to use the first method.

What is a Stroke?

During an engine’s combustion cycle, the piston moves up and down in the cylinder. Top Dead Centre (TDC) describes the position of the piston nearest to the values.

Bottom Dead Centre (BDC) describes the position of the piston farthest from them. The movement of the piston from the Top Dead Centre to the Bottom Dead Centre is known as stroke.

The movement of the piston from the Bottom Dead Centre back to the Top Dead Centre is also known as stroke.

The total process of what takes place in the engine is known as the combustion cycle. We have to have a clear understanding of the combustion cycle before we move on to 2-stroke and 4-stroke engines. The following make up the combustion circle.

• Intake: As the piston moves down the cylinder, a mixture of air and fuel is drawn in.
• Compression: As the piston moves down, a mixture of air and fuel is compressed.
• Combustion: A spark that ignites the gas is produced by the spark plug. This will cause an explosion and the piston is pushed down by the explosion.
• Exhaust: The burned gas is pushed out of the engine as the piston moves upwards.

This kind of engine has but two strokes, which are, compression stroke and power stroke.

For the engine to work, it combines multiple functions into a piston movement. When fuel and air are pulled into the cylinder, it is known as a compression stroke.

The piston is pushed downs by an explosion caused by the spark plug. The push down of the piston uncovers the exhaust port.

Pressure from the cylinder then drives the exhaust out of the port. As the piston is pushed down even further, new fuel and air will be drawn. This exposes the intake port. A combination of these three processes makes up the power stroke.

In a 2-stroke engine, the exhaust port and intake port are the same. It is known as power stroke because these processes produce the actual explosion that in turn creates the power. Concluding, in a 2-stroke engine, a complete cycle demands for double piston strokes.

2-stroke engines are straightforward. They do not have valve. Their weight is small because they have few working parts.

Their fuel tank is one. You mix fuel and oil before you put them in the tank. You should mix the fuel and oil very well before filling the tank.

If you do not, it will spoil the engine. The mixture should be in accordance with the oil/gas ratio as directed in the machine’s manual.

Applications:

2-stroke engines are commonly used in small machines, such as weed eaters and chainsaws.

They are racers’ choice of engine. The reason is that they are able to generate more power, because of their lightweight.

They have the ability to run, their position notwithstanding. They dominated the old lawnmowers. Even presently, it is still the choice of many people, because its power output is high.

Disadvantages of 2-stroke engines :

True to its name, this engine operates on four strokes. They are compression stroke, power stroke, exhaust stroke, and intake stroke.

When a mixture of air and fuel is compressed on a piston, as it is moving up, it is called a compression stroke. As the spark plug produces a spark, the gas is ignited and there is an explosion. This is called combustion stroke.

The explosion will push down the piston. As the piston moves upwards, it pushes the burned gas out.

This is known as the exhaust stroke. As the piston moves down the cylinder, a mixture of air and fuel is drawn in.

This is known as an intake system. Finally, in every two revolutions, power is produced once. All of these are known as 4-strokes.

In a 4-stroke engine, the oil that lubricates various parts of the engine is not consumed. It flows back to the crankcase.

Valve train is well protected in the 4-stroke engine and the engine is kept clean. The oil is retained in the crankcase.

You have to change the oil after a number of hours. Do not forget to check the oil level regularly. Port for oil and gas are separate.

You have no need to mix the oil and gas before you fill the tank. You will see the ports on the machine and pure the fuel.

Their weight is big because so many functions take place in them. In view of the system of oil flow in them, they can only operate in their upright position.

Their environmental friendliness has earned them popularity these days. A lot of modern lawnmowers make use of 4-stroke engines a lot.

Advantages:

• They exhaust little smoke.
• Their noise level is low and they are reliable.
• They are better than a 2-stroke engine and last longer.
• You do not need to mix oil and gas, therefore it does not easily spoil as the 2-stroke engine.
• Running cost is reduced because oil and gas is not mixed.
• Their pollution rate is low.
• Their running is smoother than that of 2-stroke engines.

Disadvantages:

• They have complicated designs and they have valves.
• They are hard to produce and repair.
• Their power is less than that of 2-stroke engines because they have less stroke fire per revolution.
• They are far heavier than 2-stroke engines.
• They are costly.
• They are hard to maintain because they have complex design.

Which Engine is Better for Lawnmowers?

A customer’s need determines the engine that should be used in a lawnmower. A 2-stroke lawnmower engine is recommended for customers who want an engine with more power.

A 4-stroke lawnmower engine is recommended for customers who want an engine with more efficiency.

The 2-stroke lawnmower engine was very popular back in the day. Today, the 4-stroke lawnmower engine is dominating the market.

Owing to its environmental friendliness, most customers are going for a 4-stroke lawnmower engine. As environmental pollution increases, people do not want the machines they use to contribute to it.

It depends on the kind of function you need to get from the engine. What you need determines the one you buy.

Is a 4-stroke engine more powerful?

There is no single answer to this question. The size of 4-stroke engines is always bigger than the size of 2-stroke engines, therefore, their power is greater.

However, a 2-stroke engine is more powerful than a 4-stroke engine of its size and weight. In summary, the power-to-weight ratio of 2-stroke engines is better.

Can you use diesel in a 4-stroke gasoline engine?

The answer is no. Do not try it. Diesel is a fuel that ignites itself. You will incur great damage if you use diesel in a gasoline engine.

What is a four-stroke lawn mower?

A 4-stroke engine has a cycle that consists of 4 strokes, in those 4-strokes, the piston goes around twice in the engine, so the spark plug fires every other rotation. There are two separate valves in this kind of engine, one for intake and one for exhaust, unlike the 2-stroke engine.

How can you tell the difference between 2-stroke and 4-stroke fuel?

You can easily tell apart a 2-stroke and 4-stroke engine. First, a two-stroke engine needs a combination of oil and fuel that ignites when the engine is in operation.

It will continually consume the oil. Second, a four-stroke engine allows oil to flow back to the crankcase after lubricating the different engine parts.

Also, if you have a 2-cycle engine, it comes with one fill port with a cap that has a fuel pump and oil can icon.

Meanwhile, the cap states the oil to fuel mix ratio, while a 4-cycle engine comes with two fill ports with each cap that separately identifies the fuel tank from the oil sump.

What happens if you put 2-cycle oil in a 4-cycle engine?

You should not worry about the values getting a little lubrication because there would not be an issue with your four-stroke mower if you use two-stroke oil. In a four-stroke engine, it can use a 1:500 ratio.

Are lawn mowers 2-cycle?

You should know that the 2 cycle mowers have been phased out in the United States. Hence, most lawn mowers are now 4 cycles.

In a 2 stroke engine, the gasoline and oil must be mixed. For a 4-stroke engine, the oil and the gasoline are separated, in two different tanks.

Lastly, we believe that this article can help you differentiate between a two and four-stroke. If you are in the United States, you can mostly use the four-stroke engine for your activities.

However, this does not mean that you would not see the two-stroke engines. The good thing is that you can use the engine on your four-stroke mower.

We hope that this article helped you understand more about the lawn mower’s engines.

How to service a 4 stroke lawn mower the proper way.

Recently one of my neighbors was having problems starting their 4 stroke lawn mower. I went over to see if I could help and it was one very neglected grass cutter. I was able to get it going for them after 1/2 hour or diagnosing the problem which turned out to be low engine oil.

So I thought I would write up a simple post on how to service a 4 stroke lawn mower once a year so you will have easy starting and a long-lasting lawn mower.

How to service a lawn mower / Briggs and Stratton, Rover, Victa

Lawn mowers are a very easy engine to service. They only have 5 major parts to them.

If any of the above is faulty you will have issues starting your lawnmower. We will break down each component to show you how to service your 4 stroke lawn mower yourself.

Lawnmower engine service

There are 2 main parts in servicing your 4 stroke lawn mower engine. They are engine oil and spark plug. I like to replace these every year, but you will be fine replacing them every two years if you have a small yard.

Start by removing the spark plug and replacing it with a new one. These are smaller than car spark plugs and are often 19mm in size. Pull off the spark plug cap and unscrew the spark plug.

Have a look and the condition of the spark plug. If it is black and sooty you could have a problem with your air filter letting in dust or bad piston rings due to wear. It should be a nice brown color on the white insulator section. If it is black and you don’t have a spare you can clean up the metal spark gap contacts with some 300 grit sandpaper. This will help in starting your lawnmower.

Engine oil should be replaced every year. Over time the engine oil will be contaminated with carbon from the piston fuel-burning process. This carbon riched oil will break down seals and cause engine wear on the piston bore and rings.

An easy way to get the oil out of the engine is you use an oil vacuum pump. The hose is put down the oil fill tube to the lawn mover. Once you have pulled out all of the oil you can refill it to the appropriate level on the dipstick. Don’t overfill the engine oil as you will have trouble starting your lawn mower.

Fuel tank service

IF you haven’t used your lawnmower over winter and it has 6-month-old fuel you may have trouble starting it. If so drain the fuel and replace it with new premium fuel. The fuel stabilizer will help for long-term storage.

You can use a manual vacuum pump to suck out the fuel or simply tip the lawn mower upside down to drain the old fuel into a container.

If there is a fuel filter attached check to see if it has captured any particles. Often dirt and dust will be filtered out.

Carburetor service.

There is not a lot to do with the carburetor and throttle cable. Check that there is the correct amount of slack in the throttle cable. Lubricate this cable with WD40 or another lubricating spray.

Check the fuel primer push button that it is not cracked or deformed. These will break down after around 10 years if left out in the weather.

If you don’t have a fuel filter attached sometimes dirt can find its way into the carburetor and block up the jets. This will require a strip-down of the lawn mower carburetor and a full clean-out. It may be best to take it to a lawnmower service center if the carburetor is clogged up and you are not confident to do it yourself but it is simple.

A symptom of a blocked carburetor on a lawn mower is starving for fuel. If you have low power and blade speed you will often have a fuel problem or a blocked air filter.

Check the fuel by pressing the fuel primmer button while the lawnmower is running it you increase in speed and power. This is a quick test to diagnose a blocked or restricted carburetor.

Removing the air filter temporarily will prove if the air filter is blocked. Sometimes it will bust easy to replace the whole carburetor with a new one. Check out this huge list of Briggs and Stratton carburetor types and compatibility.

Below is a great video on how to clean the carburetor on a lawn mower.

The air filter on your lawn mower should be rinsed out or replaced every 2 years. To clean an air filter rinse it in a bucket of warm soapy water and fully dry in the sun but only the sponge type of filters. Spray it down with air filter oil. You can also use regular motor oil on your air filter but don’t use too much or it will impede airflow. Squeeze out the excess, you only need a fine coating.

Some lawn mowers use a cartridge air filter. These will need to be thrown out and replaced every 2 years or earlier if used in dusty areas.

Making a foam air filter

Most lawnmowers use a universal air filter. These are easy to make from a thick piece of foam sponge. It is the same foam used for washing your car. Use the filter housing as a template and use a sharp knife to cut around the edges. They are great small engine foam air filter material.

Then trace out the center hole for the carburetor intake. I used a 30mm hole punch but you can cut these out with scissors or a sharp knife.

Make sure it all fits and then coat the DIY air filter with some air filter oil or use the same engine oil as your lawnmower. Congratulations you just saved yourself some money.

Checking cutting blades

Every year check over the cutting blades. Over time the lawnmower blades will become worn, and dull. They tend to lose the ability to throw the grass into the catcher when worn.

Make sure they have the fins that will create the turbulence required to move the grass into the catches. The blades over time will wear especially if you are mowing over rocks, sticks, roots, and tough grass.

To replace the lawnmower blades you will need a socket set and a wire brush to clean up all of the dirt that will form over the bolt.

Lawnmower won’t start after sitting for a while

If your lawn mower won’t start after sitting for a while then it is usually caused by dirty old fuel. Empty the fuel from the lawnmower tank and replace it with fresh fuel. Clean the spark plug while you are at it for a strong fresh spark.

Check for spark by removing the spark plug and connecting it to the lead. Place the spark plug on the metal engine frame. Pull the starter cord a few times and look for a spark. I don’t recommend holding onto the spark plug while pulling the cord as you will get a nice jolt.

Screw in the spark plug and tighten to the required torque. Make sure to prime the fuel by pressing the primer plunger a few times. It should start to firm up once it is primmed. Pull the cord a few times and then prime some more if it won’t start.

I use a product called Stabil start your engine. It comes in a spray can and is like a high octane boost for your fuel and engine. Just spray it into your carburetor with the air filter off. I guarantee if you have a good spark, your lawnmower or whipper snipper will start right up.

How to fix a lawn mower that won’t start

Most pull starting problems with lawnmowers come down to fuel, spark, and oxygen. If you are missing any one of them then your lawnmower won’t start.

• Make sure to have fresh fuel, anything older than 6 months should be discarded safely.
• Clean and inspect your air filter yearly.
• Replace your spark plug every 1-2 years. Make sure it is clean and provides a good spark.
• Use some STA-BIL Start Your Engine spray.

Electrical problems are rare on lawnmowers as they are very simple machines. Sometimes on 4-stroke lawnmowers, there is a low-level engine oil switch that can shut down the electrical circuit and prevent it from starting. Top up the oil level or replace the sensor if it is faulty.

Both 4-stroke and 2-stroke lawn mowers require priming of the fuel. Most times you only need to prime the fuel bulb 3-4 times. I have repaired an older Briggs and Stratton lawnmower that needed priming 6-8 times before the grass cutter would start.

You can flood the carburetor and this is bad as well so go easy on the priming. Read the owner’s manual, but as the lawnmower gets older you may need to prime the fuel an extra pump or two.

Check or fuel or air leaks, this can cause a lean or rich fuel mixture which will make your lawnmower hard to start.

Sometimes there is no such thing as an easy start lawnmower. You have to pull and pull and pull. But if you get the fuel, spark, and air mixture correct you should have no problems starting any lawn mower on the 1st or 2nd pull.

Lawn mower died while mowing and won’t start

First, check for fuel in the tank most often you have run out of fuel. Top up if required. If you have good fuel then next check the spark plug lead that it hasn’t fallen off the plug. If it is on good then remove the spark plug and check if it is dirty. A black and dirty spark plug will make it hard to start. Clean the spark plug with some 300 grit or finer sandpaper.

If you have fuel and spark then check the air filter that it is not clogged or disintegrated. Over time these foam filters can break down and clog the carburetor. Replace the filter and clean the carburetor.

Check the oil level in a 4-stroke engine. Sometimes these engines have a low oil level switch. This will cut power to the engine. Top up the lawnmower engine oil to the recommended dipstick level. Most lawnmowers use 10-40 engine oil.

Lawnmower starts then stops

If your lawn mower is constantly starting and then stops it is often a fuel problem. I have seen very dirty carburetors with this symptom. It is literally starving for fuel. Pull apart the carburetor and clean out any debris. Flush out the fuel tank, and clean the fuel filter if it has one.

Most often you will find mud and grass clippings inside the carburetor that needs removal. Flush it with carburetor cleaner and poke out any small holes with a paper clip. Screw the carburetor back onto the lawnmower. Replace any seals as needed.

Lawn mower pull cord stuck

Sometimes the lawn mower pull cord can become stuck. There are three possible reasons for this.

• Jammed blades
• Rusted spring or ball bearings in the pull cord starter.
• A broken pull starter cord

Check that the rotor blades are not jammed by turning off the fuel, setting the throttle to stop, remove the spark plug cap, and tilt the lawn mower on the side. Slowly rotate the cutting blades to see if they move. If they don’t you either have something jamming the blades or you have a seized engine.

Remove the offending object. If it is a seized engine go buy a new or second-hand lawn mower as it will be cheaper to replace rather than repair.

If you have an issue with the pull cord starter you will have to take off the top starter. Often the ball bearings in the pull starter can become rusted and will need some lubrication.

Broken pull starter cords and springs can also be a problem over time. I have replaced my cord with some basic thin rope found at my local hardware store. It is much cheaper than the real thing but does the same job.

Conclusion

I have seen well-maintained lawn movers last over 30 years. For a machine that is often neglected, stored out in the weather, and smashed around, lawn mowers are built tough.

Stick with well-known brands like Briggs and Stratton, Victa, Rover and you will have no problems getting parts. Some Chinese lawn mowers are cheap but they are often low on power and hard to start. Parts are also a problem.

Be sure to service your 4 stroke lawn mower every year and you will have perfect running and easy starting every time.

I am a qualified Industrial Electrician for the past 20 years and I love to share my knowledge on home repair and maintenance jobs.

I love fast toys like Motorcycles, Cars, Jetskis, Boats, and Computers so writing about them is easy. Working on them is fun. To keeps costs down I do all my own mods, repairs, and servicing. These skills I want to share with everyone. DIY is a skill everyone can learn.

Two Stroke or Four Stroke – today we settle the age-old argument

To mow by two or four stroke – today we pull together the hard facts to find out which is best to maintain your lawn.

It’s been discussed over beers, battled over the back fence and has divided families and friends for years, but today, we delve into the age-old dispute of the two stroke versus four stroke lawn mower – and we guarantee a clear winner!

For professionals who care for large scale lawns that need to be cut at shorter heights, there’s no doubt that an engine powered cylinder mower produces the best cut. But unless you’re looking after some of the Central Coast’s best golf courses or bowling greens, such as those we have here at The Greens The Entrance, most of us are familiar with the good old rotary lawn mower.

In 1952, the Victa Mower company produced the world’s first lightweight rotary mower right here in NSW. Demand exploded for the new innovation and the humble Victa mower soon became a world renowned product. It was this two stroke phenomenon that kept Australian lawns looking freshly cut, well manicured and made mowing the lawns a breeze. No more pushing and pulling a manual cylinder mower back and forward, simply start the mower and push for a luscious manicured yard.

All of the early Victas were made using a two stroke engine and there are some clear benefits of a two stroke mower.

The PROs of a 2 stroke

The first win for a 2 stroke mower is simplicity. 2 stroke engines contain less moving parts and are cheaper to build making the cost of a two stroke mower less than that of a four stroke.

Weight is also a factor. 2 stroke engines are much lighter than four stroke engines. This was a huge factor back in the early days of push mowers when engine technology wasn’t as advanced as it is today. Larger 4 stroke engines were a lot heavier and bulkier making the two stroke a clear winner when Victa began producing mowers.

Another benefit for the old 2 stroke is that less maintenance is required. 2 strokes take a mix of oil and petrol into their fuel tank meaning there’s no need to perform an oil change once a year – simply mix the oil and fuel and go on your way!

Lastly, a two stroke mower has the potential to produce more power from a much smaller engine – however, we’ll talk about this later on as the torque created in a four stroke wins out here.

The PROs of a 4 stroke

The first, and arguably one of the most important points in favour of a four stroke engine is a cleaner, more efficient burning of fuel. 2 stroke engines burn the petrol/oil mixture in a very inefficient way, meaning that more pollution is put into the air. Because of their environmental inefficiency, the manufacture, production and sale of new 2 stroke lawn mowers is banned in Australia. To illustrate how inefficient 2 stroke mowers are, almost ⅓ of the petrol/oil mixture you put in is dispersed out into the air while running the mower. That said, it’s still perfectly legal to use and even repair your existing 2 stroke lawn mower.

Keeping the environment in mind, the 4 stroke mower is much more fuel efficient. You’ll use a lot less petrol mowing the same sized lawn and these days, with the price of petrol, that’s got to be a big factor in your choice of mower. Most tests have found that a well maintained 4 stroke engine will use ⅓ of the equivalent petrol of a 2 stroke mower, this combined with the fact that 2 stroke engines have mostly remained the same since the 1940s is a clear indication that the 4 stroke wins here.

No need to mix oil and petrol

Who has time to work out ratios of oil and fuel levels. With a 4 stroke mower, simply fill up your jerry can at the petrol station with regular unleaded petrol and put it in the mower. Yes, you do have to keep an eye on the oil level but it’s not hard to check the dipstick every few weeks. A service on your 4 stroke mower is only needed once a year in most circumstances and if you’re not comfortable changing the oil yourself, it’s a standard task for any local mower shop – one that also doesn’t come with a hefty bill.

Have you ever come in after mowing your lawn with ringing in your ears? Or had a neighbour complain about your mower noise? That’s likely because you’re using a 2 stroke – they’re much louder! Therefore, another big advantage of a 4 stroke mower is its noise/decibel level which is far lower than that of a 2 stroke mower.

Even though the smaller 2 stroke engines can run faster, they don’t have the torque that a 4 stroke mower has. If you’re not sure what torque means, it equates to rotational force which means that there’s more power in the spinning mower blades, this means that thicker and longer grass is cut more easily using a 4 stroke mower – you simply can’t argue with physics.

The verdict

We know that there’ll always be die-hard fans of the old 2 stroke mower engines, and we don’t blame them. When they were released, 2 stroke lawn mowers were simple, effective and at the time, efficient. Up until 2016, Victa was working hard to economise and reinvent their 2 stroke engines, but decided to pursue their 4 stroke models only. If you’ve still got one, and maintain it well, keep using your 2 stroke, properly maintained and cared for, a 2 stroke will do the job it’s built for, cut your lawn – and it’ll do it well, albeit a little noisier.

Hands down and based purely on the technical factors of environmental impact, petrol consumption, noise, torque and reliability we choose the 4 stroke to mow our lawns. You can’t beat the simplicity of filling the fuel, the ease of pushing the mower through thick grass and the serviceability of a good 4 stroke.

Don’t forget, after you’ve cut your grass, we recommended a nice cold beer – and we’ve got it on tap at The Greenkeepers Shed. If you’re a local of The Entrance, Long Jetty or Blue Bay, pop down after you’ve maintained your lawn and let us pour you one.

What Is The Best Oil For A 4-Stroke Mower?

Choosing the correct oil can make a huge difference in how your 4-stroke lawn mower runs, but you aren’t sure what is the best oil to use. Don’t worry! You are on the right page, and we are here to help. We did the research, and here’s what we found.

The best oil for use in 4-stroke lawn mowers is grade SAE 30. The synthetic variations, SAE 5W-30 and SAE 10W-30 can also be used for improved engine performance and longer serviceability life.

Using the correct oil is crucial for the lawn mower’s performance and long serviceability life. It ensures that the equipment runs at its best. In this post, we will dig deep into what makes the best oil type and brand under certain conditions. We will also discuss the consequences of using the incorrect engine oil type. Let’s begin!

Why Choose The Best Oil For 4-Stroke Lawn Mowers?

For homeowners who enjoy caring for their lawns, the lawn mower is their best friend. As such, proper care and maintenance are crucial for the engine to perform effectively. The lawn mower engine should be operated using the correct oil.

Oil is the main ingredient to keep the engine running. The lubricating and cooling capabilities of oil can’t be understated. It makes all the moving parts of the combustion engine run smoothly. The engine parts can work at high speeds and even at extreme temperatures.

However, not all engine oil is formulated to be the same. Each has unique elements and viscosity grades that let the 4-stroke lawn mower run smoothly at certain air temperatures.

Every user must determine what engine oil type meets his mowing and lawn mower’s requirements.

Choosing The Best Oil For A 4-Stroke Mowers

With the advent of technology, choosing among various engine oil types in the market can be challenging. With the correct oil, it affords prime engine health and longer useful life. Whether you have a walk-behind or a ride-on mower, the following is a helpful guide to knowing the best oil.

Standard Oil

SAE 30 is the standard oil for 4-stroke lawn mowers. Here are its elements:

• Choose this oil type if you mow in a warm or hot climate, (a t emperature range is 40-100 Fahrenheit or 4-38 Celcius). Even if you live in colder regions, you won’t start mowing until the temperature is warm again.
• Specially formulated for small to mid-size engines. 4-stroke lawn mower engines fall into this category.
• Best for 4-cycle engines. Nowadays, most lawn mowers in the market are designed with 4-cycle engines, and 2-cycle engines are becoming less common.
• Highly adaptive since the viscosity doesn’t alter due to its wide operating temperature range.
• A non-detergent motor oil, best for small engines. It contains no additives that trap dirt and dissolves oil sludge until the next change oil.
• Economical and flexible. This is the same standard oil you can use in your car and truck.
• Commercially available in hardware, automotive shops, DIY shops, and similar establishments, hence, accessibility is not an issue.
• Endorsed by Briggs and Stratton, the leader in small engines.

Synthetic Oils

Synthetic oils are more refined and afford improved performance and higher protection for the lawn mower engine. The synthetic variations that can be used are SAE 5W-30 and SAE 10W-30.

SAE 10W-30 is thinner oil, perfect for low temperatures below 100 Fahrenheit.

SAE 5W-30 is much thinner, perfect for extremely low temperatures; that is, the best bet for icy climates of up to.20 degrees Fahrenheit.

• With the same viscosity grade of 30, these are fine substitutes for SAE 30.
• Artificially blended with chemical compound additives that make them slippery, thus minimizing friction, perfect for providing lubrication in cold weather.
• Undergoes a rigid process to remove impurities, thus prolonging the serviceability life of the engine. It protects the engine from rigid wear and tear.
• The only drawback is that it is more expensive.

You might be interested to learn about engine oil at low temperatures. We have these posts for you:

What Are The Recommended Brands of Engine Oils for 4-Stroke Mowers?

Here are some of the recommended brands of standard oil SAE 30 and its synthetic variations that can be used for 4-stroke lawn mowers:

This is the Husqvarna brand, specially formulated for 4-cycle engines of mowers. It optimizes engine performance and minimizes engine deposits to protect from sludge and varnish. It contains additives to minimize corrosive and mechanical wear.

This SAE 30 for 4-stroke engine oil is available on Amazon. Check it out.

This is the Royal Purple brand which can be bought in 32 ounces in a bottle or can. It affords your lawn mower better protection from corrosion and improved fuel efficiency. It contains antioxidants to prevent oil from degrading at high heat.

This SAE 30 motor oil is available on Amazon. Check it out.

The STP brand of premium small engine oil is recommended for SAE 10W-30. This is specially formulated for use in push mowers and tractors. It is an all-weather synthetic oil that can be used both for cold and warm climates. Not only during operation but also storage between mowing seasons, your machine is protected from corrosion by keeping the engine components clean. This brand is packaged in 32 fluid ounces in cans.

This STP 4-cycle oil is available on Amazon. Check it out.

The Briggs and Stratton brand SAE 5W-30 is a fully synthetic oil that is perfect for extremely cold temperatures. Your mower can operate smoothly on wet grass and withstand slippery and rough terrain. Though relatively expensive, this brand has earned exceptional product reviews from its users.

This Briggs Stratton 5W-30 is available on Amazon. Check it out.

Understanding Engine Oil Codes

When you shop for engine oil for your 4-stroke lawn mower, aside from the different brands, don’t be daunted by the various numbers and codes printed on the bottle label. Each code explains how well the oil performs in different weather conditions. The o utdoor temperature has a direct impact on engine oil viscosity or weight. Viscosity measures the thickness or consistency of oil during specific air temperatures.

The Society of Automotive Engineers (SAE) sets the industry standards for engine oil types. The numbers displayed on the packaging label mean the oil’s viscosity, ranging from 0 to 60. Higher numbers mean high or hot temperatures. The higher the number, oil becomes less viscous or lighter. Therefore, higher numbers are used for warm weather. At low or cold temperatures, oil viscosity increases, or oil gets thicker and heavier. Hence, low numbers work for the cold weather.

To illustrate, SAE 30 is a monograde oil since it displays one viscosity grade of 30. This is rated for hot viscosity. This explains why it is limited to use in warm temperatures only.

The synthetic versions, SAE 5W-30 and SAE 10W-30, are multigrade oils since they contain two numbers, separated by ‘W,’ which stands for ‘winter.’ The preceding number means viscosity at low temperature, while the number after W translates to viscosity at high temperature.

Multigrade oils, in contrast to SAE 30, have a wider temperature tolerance. This explains why they can be used in extreme temperatures.

For example, a lower number after W, such as W20, isn’t a good choice because it is very thin and cannot properly lubricate. This can cause engine overheating.

In SAE 5W-30, the grade is much lower before W, perfect for cold temperatures. This explains why this grade is used for extremely cold or icy climates.

Learn more about engine oil types in this post:

What Happens If Incorrect Engine Oil Type Is Used?

You can’t just use any oil in your lawn mower, so ensure you’re using the recommended engine oil in your machine. Using the incorrect oil type may damage the mechanical parts of your 4-stroke lawn mover. At worst, it may damage the engine, which can cause serious issues.

Another serious consequence is that it may put your mowing operation on hold, thus causing more losses and inconveniences.

Here are the effects of using the incorrect engine oil type:

• less friction on the moving parts that will cause overheating quickly
• oil leaks due to thin oil; it will just flow freely and drip like water
• oil lacks stickiness and is unable to trap dirt resulting in more residue
• undue stress on the moving mechanical parts due to less lubrication
• faster wear and tear of the engine and the machine as a whole
• costly repairs to the engine or even the whole equipment

How Much Oil Does A 4-Stroke Mower Take?

The amount of oil needed for a lawn mower engine depends on the size and make of your 4-stroke lawn mower. Generally, you will need between 400-600 ml of engine oil. Ride-on mowers typically need between 1-2 liters of oil. This is the volume of oil that you will need during every oil change.

Just a tip, do not mix old oil and new oil. If there is still unused oil at the crank when you start to have an oil change, you need to discard them before pouring new oil. You must drain the old oil from the engine crank and discard it properly.

If you wish to learn how engine oil is disposed of, this post is worth reading:

The Takeaway

The best oil is the correct oil! It is important to use the correct oil for your 4-stroke lawn mower for good lubrication and to function effectively. This way, you will enjoy your lawn care equipment for many more years.

Air temperature and oil viscosity are the two important factors when choosing the best engine oil type. Opt for SAE 30 for warm temperatures. And SAE 5W-30 and 10W-30 for warm and cold climates.