In this post, we will be comparing some oils for small engines. The STP 4-cycle, Briggs and Stratton, Mobil-1, Redline 10W, and Honda PK2 are the brands that are included in this list. There is also a buyer’s guide included to provide you with more information and tips. 

Importance of lawn mower oil

Lawn mowers have a small combustion engine that consumes fuel for operation. No matter how small an engine might be, there are still internal parts and mechanical components that work vigorously at high speeds and temperatures.

The oil you use should have an efficient lubricating and cooling action to prevent the overheating of the engine and to keep everything running smoothly. 

What is the action to be taken for that? Try using different oils and comparing the engine sound. 

STP 4-Cycle Oil Formula, engine care for lawn mower

The STP synthetic SAE-30 4-cycle oil provides great lubrication for the motors of small engines like those of lawn mowers and lawn tractors. Despite the fact that it is only a single-grade oil, the formulation can compete with multigrade oils when it comes to performance in various weather conditions. 

The probability of thermal degradation is greatly reduced with the presence of antioxidants. The detergents also minimize the accumulation of carbon deposits along with the corrosion inhibitor that protects the machine from rust, especially if it is usually stored outdoors and is prone to moisture exposure. 

Versatility is the STP 4-cycle oil’s strong suit. It works well with a lot of different small engines and the majority of mower types. Its 32-oz bottle is reasonably priced. 

Briggs And Stratton Premium Oil In Mower

One of the top names in the lawn mower engine industry is Briggs and Stratton. They are known for their heavy-duty engine performance, that other popular brands use their products to integrate with their own. 

It’s only fair that with their top-notch engine manufacturing, they would also make oil products that are compatible with their 30W small machines. 

A customer review on Amazon said this about the product:

“Bought a brand new lawnmower and didn’t want hubs to blow this one up too because he forgot to put oil in it.” 

It’s a witty review and a casual reminder to always remember to put oil into the engine before using it, not to risk damaging it. 

Honda PK2 Motor Oil

Honda hardly needs any introduction because it has established itself as one of the world-renowned brands not just in the automotive industry but in other fields as well. For decades, Honda has not disappointed its loyal customers. 

Their PK2 motor oil works perfectly with Honda lawn mowers and grass cutters. Of course, it only makes sense that they would formulate a motor oil for their own engines. It could work for other mower brands as well, provided that they have a four-stroke engine. 

The Honda PK2 is a kind of SAE 10W-30 oil. This is how you decipher the code: the SAE acronym means Society of Automotive Engineers.

This is an organization that sets grading standards for automotive equipment. The numbers before and after the letter W indicate the measurement of the viscosity of the oil at cold and hot engine conditions, respectively.

The lower the value, the lesser the viscosity of the oil at the cold temperature of the engine. This means that it will easily flow. 

Since there are two values, it means that the oil works in both temperatures and contains a viscosity index improver in its formulation that makes it versatile in whatever environment it is in.

It will adjust its own flow resistance depending on the temperature levels. The letter W simply means ‘winter,’ and that indicates the season when it is best used. 

The drawback of adding VIMs is their tendency to undergo shearing (a phenomenon when they will lose their viscosity increasing capability at high temperatures), which is their main purpose.

However, with the Honda oil, that is something you do not have to be worried about. It may cost you a little extra, but it’s definitely worth it. 

Mobile-1 Oil In Mower

The Mobil-110W is a regular SAE 30, regular, non-synthetic motor oil. It is a clean oil and very engine-friendly, which is ideal for your machine. 

Redline 10W-30 Oil In Mower

This oil does not reduce the motor noise, so you should expect a little bit of annoying noise from your engine even when you’ve already poured oil into it. 

Especially when you add a mulching blade (so you won’t have to use a bagger) to keep the lawn clippings inside the mower deck, and if the motor is also quite powerful, then oil won’t be able to reduce the emitted noise when the mower is being used. 

Regardless, the Redline 10W-30 is still a great voice for fully synthetic oil. For cold temperatures, the Mobil-1 is ideal. 

Both the Moil-1 and Redline 10W are usable during cold seasons like fall and winter at a pretty high cost.

While Redline specializes in maximizing the power of the engine, the Mobil-1 can also be a good alternative. However, the best choice would be Briggs & Stratton SAE 30 oil because it is more affordable at $8 for a 48-oz bottle at the same performance.

It works well during cold weather, especially for small engines. B&S gives a lot of value for your money with its efficiency. 

Redline advantages

  • It can be used all year round, no matter what season, primarily intended for winter.
  • Reduced thermal breakdown due to versatile viscosity
  • Has added viscosity index improvers
  • Two bottles per package at discounted price

Redline disadvantages

  • Pricey

Lawn mower oil types

There are different grades of motor oils. They are categorized according to viscosity and the state of the oil under various temperatures. Most of the lawn mowers made today use four-stroke engines, burning gasoline straight from the pump. 

The motor oil is added separately to the engine crankcase. The 10W30 is quite a common grade for motor oil and works well for lawn mower engines. The manual of your mower will specify the grade of the motor oil that it uses. 

Usually, engine oils that are compatible with conventional cars, trucks, and other vehicles are also compatible with lawn mowers. Along with the viscosity rating, there is also a service rating for established oil brands.

The recommended ratings that you should look for are SF, SG, SH, SJ, and higher. 

  • Single grade oil: This type of oil grade does not contain viscosity-altering additives and works only at temperatures around 100°C.
  • Multigrade oil: This one works well for a wide range of temperatures and contains additives to adjust viscosity. 
  • Synthetic blend oil: This involves a mixture of natural and synthetic oils plus additives that will improve its performance at cold temperatures.
  • Full synthetic oil: This one is entirely synthetic with major modifications and additives for maximum performance in heavy-duty and commercial engines.

Lawn mowers with two-stroke engines have a slightly different motor oil requirement. These types of engines consume both gasoline and oil at the same time. This leads to the inevitable mixing of the gasoline and oil before it enters the tank. 

The common gas-to-oil ratio is 30:1 (4-1/4-oz. of oil for every one gallon of gasoline). It can also be 50:1 (2-1/2-oz. of oil to one gallon of gasoline). Not to worry because the manual usually provide specific measurements. 

However, two-stroke engines are not very common anymore today due to problems with emissions, but there are still people who use them. Again, it specifies in the product manual whether your mower is a two-stroke or four-stroke engine, so it’s best to refer to it to be sure. 

A buyer’s guide to lawn mower oils

You should determine the appropriate oil to use for your mower so you can keep it running smoothly and make it last for a long time. This will benefit you greatly in terms of the usability and lifespan of the equipment.

For the next part, we will be providing some technical information about lawn mower oils to serve as your basis. 

2-cycle vs. 4-cycle oils

2-cycle oils are commonly used by smaller equipment with simple engines like weed trimmers and chainsaws. Equipment with bigger engines, such as lawn mowers and tractors, use 4-cycle oils. 

Since 2-cycle engines do not have a separate lubrication system, the motor oil mixes with the engine fuel, and that is what circulates the equipment. The ratio needs to be accurate. 

2-cycle motor oils have also shown to deteriorate faster despite their ease of use in cold temperatures. The common practice done by consumers is to mix different 2-cycle oils together to maximize lifespan and efficiency. 

4-cycle engines, on the other hand, have a separate circulating pump, so the oil is poured into a designated port and does not mix with the fuel. This kind of engine proves to be better in terms of durability, fuel efficiency, and reduced emissions.

What motor oil should I use for my lawn mower?

Engine type, quality, and environmental conditions are a few considerations to consider when selecting a motor oil for your engine. You should know the specifications of the engine that your lawn mower has. 

If it is a 2-cycle engine, then a 2-cycle motor oil should be used. You should not use 4-cycle engine oils for simpler engines because the tendency is that they may not be able to take the weight of the oil.

Simpler engines are designed to consume oils with low molecular weight. Putting in heavy oils will damage the motors.

You can always refer to the manufacturer’s manual for specific instructions and information about oil compatibility. Checking is always a wise practice to prevent irreparable damages because lawn mowers are not exactly cheap. 

Below is a list of oil types that you can choose from based on various climates:

  1. SAE 30 – This is the safest choice for most conventional engines. It is suitable for warm temperatures and designed for use in smaller engines. 
  2. SAE 10W30 – For cold weather, this is the go-to oil, but consumption is quite heavy. 
  3. Synthetic SAE 5W-30 – This oil has more weather versatility which means it works for both warm and cold temperatures with lesser consumption. 
  4. SAE 5W-30 – This works great for extremely cold temperatures. 
  5. Vanguard 15W-50 – This is the common oil grade used in commercial lawn cutting and heavy use. 

The indications “For Service SF, SG, SH, SJ” are also important factors to look for. Other additives should also be avoided. 

What is the meaning of the numbers?

The code is a summary of the capacity of the oil to work under different weather conditions. Of course, the size of the mower and the climate matter a lot when choosing the oil for your engine. 

The SAE (Society of Automotive Engineers) developed a measurement for oil grades. The numbers signify the viscosity of the oil in warm or cold weather. The lower the numbers, the better the flow at cold temperatures. 

Multigrade oil can work great at both warm and cold temperatures. You know it’s multigrade when there are two numbers separated by a letter W – which means winter.

The number to the left indicates viscosity at low temperatures, while the right indicates viscosity at high temperatures. 

A Chart Of Viscosity Grades For Engine Oils

Why is a synthetic oil used for lawn mowers?

Synthetic oils are generally safe and reliable to use for your lawn mowers. They possess a lot of beneficial qualities, such as a longer life span for your engine and less risk for wear and breakdowns due to their increased fluidity.

Regardless of hot or cold temperatures, synthetic oils work efficiently. They are able to adapt to what the engine needs. And because lawn mowers tend to heat up when used, synthetic oils have the ability to cool it down.

The lubricating power of synthetic oils is better than regular oils. You can be assured that your mower engine will maintain and even improve its efficiency, and it will also be protected from deterioration.

Synthetic oils also filter dirt and debris from your engine. When you perform an oil change, the accumulated dirt will also be removed. 

Synthetic oil benefits

  • Low consumption
  • Clean and reduced emissions
  • Lessen engine friction
  • Fewer engine deposits
  • The versatility of function in high and low temperatures
  • Faster start time of engine
  • Long lifespan and interval between oil changes

Comparison of full and blend synthetic oils

Full synthetic oil is the pure form of synthetic oil. The base liquid is synthetically formulated and contains additives for improvement of performance.

This is the type that most consumers use because it possesses most of the benefits of synthetic oil. 

However, it costs about 30% more than blended synthetic oils. But for us, this is a small price to pay in exchange for what it offers. 

What makes synthetic blend oils cheaper?

From the name itself, this type is a blend of synthetic and mineral-sourced oils. They offer almost the same benefits as fully synthetic types, but they cost less. 

The reason for this is that blended types do not perform as well as fully synthetic types, but the interval between oil changes is almost the same. 

Either one works great for your lawn mower engine. They both maximize the engine life span. Whichever one you choose, it will still benefit you.

Benefits of full synthetic oil

  1. Maximum protection and performance 
  2. High engine efficiency
  3. Long time before the next oil change

Benefits of synthetic blend

  1. Performs better than conventional oil
  2. Cheaper than full synthetic oil

Mobil 1 (10W30) vs Redline 10W30

The Mobil 1 oil reduces engine friction. It addresses consumer concerns like wear protection, optimal engine performance, and versatility in both cold and warm temperatures.

The brand already has a good reputation, and a lot of consumers have nothing but good things to say about it.

It does a good job of maintaining viscosity and reducing losses and damages by reducing the probability of malfunctions, and there is also a long interval between oil changes. This brand also has a lesser number of engine deposits compared to other oil brands in the market today. 

Highlights of Mobil 1

  • Synthetic oil
  • Performs well in high temperatures
  • Maximum mileage
  • Longer oil change interval (1-2x a year only)
  • Neutralizes acids for engine protection

Redline oil, on the other hand, cleans and cools your engine at the same time. The detergents added to it helps in reducing the friction in the engine mechanism, all the while protecting it from wear and keeping it clean and smooth running.

Redline oils go through various standard quality testing and processes to pass the regulatory standards that are deemed safe and effective for use.

There was a lot of positive feedback for it saying that their mowers run better and emitted less noise with the use of the Redline oil.

Highlights of Redline

  • Synthetically formulated for engine protection
  • Cooling additives
  • Stable during hot weather
  • Detergents for lesser friction and increased wear protection

As you can see, Mobil 1 and Redline offer similar benefits and have the same advantages. Both have great customer feedback with the better performance exhibited by their engines after using the oils. 

It’s hard to choose between the two. It all really boils down to engine compatibility and what additives go well with your engine. We advise you to just refer to the product manual to be sure. 

Checking oil levels

  1. Remove the dipstick cap by pushing down and twisting counterclockwise.
  2. Pull out the dipstick and wipe with the clean rag for an accurate reading. 
  3. Before inserting the dipstick back, see to it that the cap teeth match the grooves on the tube. 
  4. Push down again and twist clockwise to close the dipstick cap. 
  5. Remove it once more and look at the oil level of the dipstick blade. 
  6. Reading should fall between the full and add marks. 
  7. Gradually add a few ounces at a time if there is a need to refill.
  8. Let the oil settle for a while before rechecking and closing.


What are the oil viscosities that lawn mowers commonly use?

Common lawn mower oils are SAE10W-30 and SAE 10W-30. The former is common for cold temperatures, and the latter is for hot temperatures. 

Can 10W40 oil be used for lawn mower engines?

Yes. It is safe to use 10W40 oil for lawn mower engines as there have been no reports that say otherwise.

So far, there has been no feedback about increased oil consumption, and the 10W40 grade performs well in both hot and cold temperatures. 

How often should an oil change be done?

For walker-type mowers, experts suggest an oil change for every 50 hours of accumulated usage. For riding mowers, every 100 hours of use is the recommended time for an oil change. 

What happens if too much oil is added?

If the oil level is way beyond the engine’s capacity, there is a tendency for excessive smoke emission, and the engine may even fail to start.

It could also lead to a decrease in the efficiency of the mower’s performance. 

What happens if the engine oil does not get changed?

There will be a definite accumulation of dirt, carbon, and other kinds of debris in the engine mechanisms if you do not change the oils. This will lead to a higher probability that the engine components may get worn out easily.

Overheating, degradation, and most likely engine failure are the possible consequences of failing to change the oil.

Can you mix synthetic and regular oil for a small engine?

There is no problem with mixing synthetic and regular oils since they mostly contain almost the same contents. However, you should also be aware that one of these oils has higher quality additives. 

While it may not necessarily damage your engine, it may alter its overall performance. There may be times when you really need to combine the two during emergencies.

If the most convenient one available on short notice is a regular oil, then you might need to combine the two. 

Mixing the two may also save you some money and even maximize your supply of both oils. It can also boost the performance of either of the two oils and can be a good first step when you want to switch brands. 

Can car oil be used for lawn mowers?

Lawn mower engines are built differently compared to car engines. Therefore, using car oil may not be safe for your lawn mower.

Factors like viscosity and oil grade should be considered first. 

Lawn mowers generally require a different oil formulation with at least SAE 30 for optimal performance. Cars, on the other hand, can already do well even with low-quality engine oils.

Lawn mowers use either 2 or 4-stroke engines. Cars use 4-stroke engines, but that does not necessarily mean that the same oil is used. There are still variances in terms of cooling mechanism and engine size. 

Why can’t a 4-stroke oil be used in a 2-stroke lawn mower?

4-stroke oil contains more additives in it which may be fatal to 2-stroke lawn mowers. Chances are, the 2-stroke engines won’t be able to handle the heavy content.

This will eventually result in damage to the lawn mower engine. 

The golden rule is to always read the product manual and just stick to whatever the instructions are to prevent damage to your engine. If the recommended oil is unavailable, you can always consult with the manufacturer to see if what you have is compatible.

Small engines usually emit more heat compared to car engines, making the former more resistant to extreme heat. 

How to change the engine oil

This is a hack that we will share with you to make the oil change process easier and less complicated.

  • Before I did any of this, I started the mower first and allowed the engine to warm up to make the oil flow out easier. I keep the engine in that position until no more oil comes out. 
  • The first thing that we suggest you do is to make a 4×4 post to elevate the engine and place the drain pan below to catch the oil. Some manufacturers advise the use of a field tube.
  • After that, simply remove the dipstick and drain the oil. It will flow easily into the drain pan underneath. Without the post, it would be harder to drain the engine oil.
  • When it’s done, set the mower upright and pour in the new oil. It might take different volumes of oil to fill it up to the dipstick mark. It’s better if you have some sort of indicator to let you know just how much oil you have poured into the engine. 


Using good engine oil is a vital part of lawn mower maintenance. This is a large determinant of whether or not your lawn mower will run smoothly and last a long time.

The best option is always the one indicated in the product manual because that has been proven during the manufacturing and testing of the equipment.

However, if you want to change it, just remember to be careful and keep in mind the reminders we jotted down on this post. 

Last update on 2023-06-06 / Affiliate links / Images from Amazon Product Advertising API

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