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How To Tell if Your 2 Stroke Fuel Is Already Mixed

How To Tell if Your 2 Stroke Fuel Is Already Mixed

Many tools use 2 stroke fuel, including string trimmers or weed eaters, leaf blowers, chainsaws, and other such powered equipment. 2 stroke fuel is a mixture of gasoline or petrol and engine oil or lubricant. Like many homeowners, you may wonder if your 2 stroke fuel is already mixed. 

The easiest way to tell if your 2 stroke fuel is already mixed is by the color. Gasoline or petrol is transparent, whereas 2 stroke engine oil or lubricant has a color, and the dye is usually blue, red, or green. You can also use the smell, paper, touch, and viscosity tests. 

You may encounter a hurdle while testing whether or not your 2 stroke fuel is already mixed if the fluid has been sitting for many months, if not years. The color, texture, or viscosity may not be easy to decipher. Read on to know how you can definitively tell if your 2 stroke fuel is mixed. 

4 Ways To Tell if 2 Stroke Fuel Is Already Mixed

2 stroke fuel is essentially a mixture of gasoline or petrol and engine oil mixed in a ratio, as recommended by a particular tool’s manufacturer. 2 stroke or 2T engine oil manufacturers purposefully add a dye to their products so that the lubricants are easily distinguishable. 

Castrol’s reddish-brown color may appear bronze in its concentrated form. Likewise, the color of Polaris Snowmobile Blue Synthetic Blend (link to Amazon) may appear almost black. However, any such color undergoes a significant dilution when mixed with gasoline. Thus, you will have much lighter shades of these hues. 

Additionally, any 2 stroke engine oil’s composition and texture are distinct from regular, midgrade, and premium quality gasoline. Thus, you can tell the two apart through visual observation, touch or feel, and a few elementary tests. Choose any of the following solutions based on your situation. 

Check the Color of the 2 Stroke Fuel in a Transparent Container

A visual inspection is the most straightforward way to tell if 2 stroke fuel is already mixed. But you should not observe the 2T fuel in an opaque container or colored vessel. You must pour a bit of the 2 stroke fuel on a white or clear container, like a transparent plastic cup or bowl. 

You cannot conduct a visual inspection of 2 stroke fuel in an opaque container. A red tank will impart its color to the fuel, and you won’t be able to tell the exact hue of the fluid. Likewise, a blue, green, or yellow gas container will make it difficult for you to check the color of the fuel. 

Premixed 2 stroke fuel will not be clear or transparent, irrespective of how long it has been in a container. All 2T engine oils have a color. This color will be evident in gasoline, regardless of the mixing ratio. Thus, if you don’t have transparent fuel, it is probably mixed with engine oil. 

Smell the 2 Stroke Fuel and Compare the Odor With Fresh Gasoline

You are familiar with the odor of fresh gasoline. So, smell the 2 stroke fuel and assess if it is similar or identical. The color aside, your 2T fuel is already mixed if the smell is subdued, not of fresh gasoline. Hence, you have 2 stroke fuel mixed with engine oil, or the gas is stale. 

Fresh gasoline or petrol has a sharp odor, which hits your olfactory sense strongly. If your 2 stroke fuel does not hit your sense of smell, the gas is already mixed, or it is bad or stale. The color and smell of 2 stroke fuel should tell you if it is already mixed. 

Touch To Feel the 2 Stroke Fuel and Compare It With Gasoline’s Viscosity

Here are the steps to conduct the touch, feel, or viscosity test of 2 stroke fuel: 

  1. Pour a bit of your 2 stroke fuel on a container. 
  2. Dip your thumb and index finger into the fluid. 
  3. Rub the two fingers to feel the texture of the fuel. 
  4. Gasoline or petrol will not linger on your skin. 
  5. Engine oil will be greasy or sticky on your fingers. 
  6. Premixed 2 stroke fuel will feel viscous and oily. 

You may be unsure about the viscosity difference between gas and oil or lubricant. In such a scenario, get some fresh gasoline or petrol in a small container. Perform the viscosity test by touching & feeling the new gas. Then, compare it with the texture of the 2 stroke fuel you have. 

Use the Paper Test To Assess the Residual Stain of 2 Stroke Fuel

The paper test is as simple as assessing the color and viscosity of 2 stroke fuel. You may use an ordinary paper towel or other materials for this test. Ideally, you should have an impervious material, but a white paper or sheet will suffice. 

Here’s how you can conduct the paper test to assess the residual stain of 2 stroke fuel: 

  1. Place a paper towel or sheet on a flat surface. 
  2. Pour a few drops of 2-stroke fuel on the paper. 
  3. Wait for a while so that the gasoline evaporates. 
  4. Check the paper towel or sheet for residual stain. 
  5. Colored or greasy residual traces imply engine oil. 
  6. A lucid or transparent stain implies only gasoline. 

The paper towel or material you use may be moist even if the 2 stroke fuel is only gasoline. Do not worry about wetness. Focus on the color, stain, and greasiness. Gasoline evaporates much faster than 2 stroke engine oil or lubricant. Thus, a stain or greasy moistness implies engine oil. 

How To Tell if Old or Stored 2 Stroke Fuel Is Already Mixed

You can tell if old or stored 2 stroke fuel is already mixed by observing its water content, color, texture, or viscosity. Gasoline will have more water as a result of condensation compared to 2 stroke fuel that is already mixed with engine oil or lubricant. 

Gasoline or petrol goes bad when stored for a long time in the tanks or reservoirs of lawn equipment or power tools. Thus, there is a noticeable difference in the color, texture, and other properties of gasoline. It is better to discard old, stored, bad, or stale fuel, whether mixed or not. 

Here’s how old gasoline looks, and you should not use this fuel in your 2 stroke engine: 

How can I tell old gasoline from fresh gasoline


Exercise caution whenever you are unsure if your 2 stroke fuel is already mixed or not. Lack of sufficient engine oil or lubricant in the fuel will damage a 2 stroke engine. Finally, depleted levels of gasoline in proportion to the engine oil or lubricant and stale fuel can damage your tool. 

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