motor oils

Choosing the Best Oil for Your Generator

Do you need a new oil for your generator but have no idea how to choose it? Then take a detailed look at our shopping guide. Besides tips and features to look for, you will also learn about the best and most reliable brands of oils we recommend.


Tip #1

As always, the first step in our shopping guide is to take a look into the User’s Guide or Owner’s Manual you got with your Generator. You will find every piece of information you will ever need inside, so don’t throw it away.

From our personal experience, information about the required engine oil is usually in the maintenance section of your manual.

MIND THEse oil features

Tip #2

The most crucial feature you need to pay close attention to while choosing the engine oil for your generator is its viscosity. As mentioned above, you can find the recommended type in the Owner´s Guide or Manual.

In most cases, you will need an SAE 10W-30.

The SAE refers to the grading system developed by the Society of Automotive Engineers. The rest of the code refers to the oil´s viscosity at different temperatures.

The first number in the code, in this case the 10W, means how well can this oil be pumped at cold temperatures. The W refers to the word winter (not the weight). The second number in the code means how well can the oil be pumped when heated to 212 degrees Fahrenheit (100 degrees Celsius) or higher.

Also, you should select a good quality detergent oil bearing the American Petroleum Institute (API) service classifications SJ, SL, SM, or SN.

However, always double-check the correct type of oil in your user’s manual and don’t rely solely on our recommendation. It may differ from one type of generator to the other. If you insert a different type of oil than the recommended, you may cause premature wearing of individual engine parts.


Tip #3

Another thing to consider while choosing the best oil for your generator is the temperature of the environment where you will be using it. Actually, this has been also pointed out in each and every User Manual we have seen.

Here is an excellent graphic that we have found in one user guide:

If you are going to use your generator in a very cold environment that allows only for very low starting temperatures, then a 5W-30 may be a better option for you. However, you need to keep in mind that this oil comes with increased oil consumption by the engine at higher operating temperatures so check its level before each use.

Know the type of your engine

Tip #4

Another thing you should consider before deciding which oil is good for your generator is to know what type of engine it uses. From our experience, there is only a small number of generators using a 2-stroke engine and a vast majority of generators using a 4-stroke engine.

Each type requires a different kind of engine oil. 

While in a 4 stroke engine you use oil and fuel separately, in a 2-stroke engine, you can either mix fuel and engine oil in a recommended ratio by yourself or you can purchase a pre-mixed solution.

Here are some bestselling oils for 2-stroke engines at Amazon.

Go for reliable brands

Tip #5

Last but not least, you should never try to save on engine oil for your generator. Preferring lower price instead of a high-quality product may cause a lot of worries later.

Rather invest a little bit more into reliable brands, such as:

  • Honda
  • Onan
  • Briggs & Stratton
  • Shell Rotella
  • Motor 1
  • Generac
  • Craftsman

We believe that all these brands are reliable and produce only high-quality products. If you want to get your supply of high-quality oils for a decent price, then take a look at deals.

Just keep in mind that different generators may need different types of engine oil.

Our top picks among oils

Honda oil for table Shell rotella for table Generac Full Synthetic for table Husqvarna XP+ Briggs oil for table
Honda Motor Oil Shell ROTELLA Generac FS Oil Husqvarna XP+ Briggs & Stratton
Mineral Oil Synthetic Blend 100% Synthetic Oil Synthetic Blend Mineral Oil
SN (API class) CK-4 (API class) SN (API class) TC (JASO FD) SJ (API class)
Check on Amazon Check on Amazon Check on Amazon Check on Amazon Check on Amazon


Best SAE 10W-30 oil
  • Well-known brand
  • Meets / exceeds SN API
  • Quick lubrication
  • SAE 10W-30
  • API SN
  • Non-synthetic

Our top selection in the SAE 10W-30 category of engine oils is the Honda Genuine Oil. This high quality engine lubricant has been created for power equipment and tools that have 4-cycle engines.

It is classified as an SN oil according to the American Petroleum Institute (API).

This means that this oil is one of the best available these days. Not only that, choosing a high quality oil such as Honda for your generator will make your engine run more efficiently, hence you will reduce your fuel consumption and save some money.

Although this oil is excellent, it is expensive (it costs almost the same as full synthetic oil). That is the reason why a lot of people decide not to get it.

Don´t forget to take a look at feedback and reviews of Amazon customers. Focus on those classified as “verified purchase”.

Other good SAE 10W-30 options:

Shell Rotella OIL

Best SAE 15W-40 oil
  • Well-known brand
  • Exceeds highest API class
  • Low oil breakdown
  • SAE 15W-40
  • API CK-4
  • Synthetic blend

Another type of oil that is recommended in Owner´s Manuals (although rarely) is the SAE 15W-40. If you need this type of oil, then our recommendation is to go for Shell ROTELLA T5. This product is a synthetic blend that combines synthetic base oils with advanced additives.

Such a blend is perfect especially for diesel engines where resistance to increased heat and stress is required. Also, this oil is classified as CK-4 or better according to the American Petroleum Institute (API).

This is the best rating for an oil used in diesel engines. The best part is, that Shell ROTELLA ensures triple protection against wear, deposits, and oil breakdown at high temperature oxidation.

The best part? This oil is not very expensive compared to other 15w-40 options.

Don´t forget to take a look at feedback and reviews of Amazon customers. Focus on those classified as “verified purchase”.

Other good SAE 15W-40 options:


Best SAE 5W-30 oil
  • Created for generators
  • Exceeds highest API class
  • Protects against deposits
  • SAE 5W-30
  • API SN
  • Synthetic blend

Another type of oil that is very often recommended by Owner´s Manuals is the SAE 5W-30. This oil is perfect for generators that will be used in slightly colder climates as it ensures easier start and better viscosity at lower temperatures.

Our best choice in this category is the Full Synthetic motor oil by Generac. This brand is well known in the market for portable generators as they themselves produce a lot of portable and standby machines. As the name suggest, this is an synthetic oil that has been fortified with advanced additive technology.

It meets the highest API SN classification (also ILSAC GF-5). 

Not only that, this oil has been deliberately manufactured for gasoline generators to provide maximum protection against viscosity breakdown. Also, it protects against formation of sludge and varnish deposits on individual parts of your engine.

Although this Generac SAE 5W-30 oil is great, engines in generators that are running in warmer climates may have increased oil consumption.

Don´t forget to take a look at feedback and reviews of Amazon customers. Focus on those classified as “verified purchase”.

Other good SAE 5W-30 options:

hUSQvarna XP+

  • Excellent for 2-cycle engines
  • Low operating temperatures
  • Low smoke formula
  • 2-Stroke oil
  • JASO-FD certified
  • Synthetic blend

Although a vast majority of generators use 4-stroke engines, there are some machines with “old-school” 2-cycle engines. If you own one and need a new oil for it, then go for Husqvarna XP+.

Husqvarna is a well known manufacturer of small machines utilizing 2-stroke engines so they have a lot of experience with formulating the proper oil as well. This semi synthetic oil is JASO-FD certified so it meets the latest standards and requirements.

Not only that, Husqvarna XP+ includes fuel stabilizer, and provides for low operating temperatures, leading to a better engine protection and lower smoke. Luckily, this oil is still on the affordable side.

Don´t forget to take a look at feedback and reviews of Amazon customers. Focus on those classified as “verified purchase”.

Other good options for 2-stroke engines:

Briggs & Stratton

Best SAE 30 oil
  • Good for warmer temperatures
  • Warranty certified
  • SAE 30 type of oil
  • API SJ/CD classified
  • Mineral oil

The second most often recommended oil by Owner´s Manuals I had opportunity to look into is SAE 30. If you have a 4-cycle engine in your generator, then you may try Briggs & Stratton small engine oil.

It has been specially created for use in all Briggs & Stratton generators. Also, this oil is a high-quality detergent oil that has been classified as SJ/CD by the API. If this oil is good enough for engineers from Briggs & Stratton, then it is a good choice for us too.

This oil provides for a good lubrication and engine protection at a moderate price. The best part? This oil is proudly made in the USA.

Don´t forget to take a look at feedback and reviews of Amazon customers. Focus on those classified as “verified purchase”.

Other good SAE 30 options:

recommended readings

About the author


handyman, loves science

Hands behind everything you see around. Matthew is the ultimate handyman. He is the expert to all things related to generators. 

When he compares the machines, he uses his comprehensive research skills combined with attention to details. If you need to pick new generator, he is your man.

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