How We Research
This page explains where our information comes from and how we check it.
It also covers how our reviews work, what we never do, and how we fix mistakes.
Key Takeaways
- Every article is built from primary sources, like owner’s manuals, the EPA and the U.S. Department of Energy.
- Each fact links to its source, and every article ends with a full list of sources.
- Our reviews are research-based. We never claim to have tested a product we haven’t tested.
- Advertisers and affiliate partners have no say in what we publish or how we rank products.
- When we get something wrong, we fix it and note the correction on the article.
Where Does Our Information Come From?
We rank our sources. A weaker source is never used to overrule a stronger one.
| Source type | Examples | How we use it |
|---|---|---|
| Manufacturer documentation | Owner’s manuals, official fuel and oil FAQs, warranty terms | The final word on a specific engine: oil type, capacity, mix ratio and fuel limits. |
| Government and standards bodies | EPA, U.S. Department of Energy, EIA, NIST, ASTM, JASO, ISO | Fuel rules, energy data, definitions, test methods and units. |
| Published research | National laboratory reports, SAE technical papers | How fuels and oils actually behave, with measured data. |
| Industry publications | Oil company technical reviews, trade groups | Technical background. We always name them as industry sources. |
| Owner reports | Forums and repair communities | Only to describe common experiences. Always labeled, never used as proof. |
How Is an Article Researched?
Every article goes through the same six steps.
1. Start With the Real Question
We look at what equipment owners actually search for. Then we list the facts needed to answer it properly.
2. Go to the Primary Source
For a specific engine, we read the manufacturer’s manual or support page. For fuel rules and safety, we go to the agency or standard that sets them.
3. Cross-Check Every Number
We compare figures across sources. When two good sources disagree, we show both and explain why.
If a number is our own calculation, we say so and show the math.
4. Explain the Reason Behind Each Rule
Knowing why a rule exists helps you apply it to your own equipment. So we explain the fuel chemistry or mechanics behind each recommendation in plain English.
5. Link Every Claim
Each fact links straight to its source. Every article also ends with a full list of sources.
6. Review and Update
Each article shows the date it was last updated. We recheck articles when manuals or regulations change.
How Do Our Product Reviews Work?
Our reviews are research-based. We don’t run a testing lab, and we won’t pretend to.
Instead, we judge products on evidence you can verify:
- Specifications and certifications, like whether an oil carries the API, JASO or ISO rating an engine maker requires.
- Manufacturer requirements, meaning whether the product matches what equipment makers specify.
- Independent data, such as published lab results and standards compliance.
- Owner experience at scale, used as supporting evidence and labeled as such.
- Value, including cost per use and shelf life.
Every review states which of these it relied on. If we ever test products hands-on, the review will say exactly what we tested and how.
What We Never Do
- Claim we tested a product we didn’t test.
- Accept money or free products in exchange for coverage or a better ranking.
- Publish specs we can’t trace to a manufacturer source.
- Present forum stories as facts.
- Use AI-generated text as a source of facts.
How Does Small Engine Lab Make Money?
The site is supported by ads and affiliate links. If you buy through some of our links, we may earn a commission at no extra cost to you.
Advertisers and affiliate partners have no say in what we publish. Read our full affiliate disclosure.
How to Report a Mistake
Found an error, or a manual that says something different? Please contact us and include your source.
We review every report. Confirmed errors are fixed quickly, and important corrections are noted at the end of the article with the date. See our editorial standards for details.