Are you wondering how to pre-mix 2-stroke oil? Need to know the oil to fuel ratio your power equipment needs?
This 2 stroke oil mix chart and step-by-step guide can help answer those questions, here is what you need to know.
Small engines generate a lot of heat, most of which dissipates into the air through cooling fins on the engine block.
2-stroke engines, like those found on lawn mowers, need additional cooling help because they don't have an internal oiling system to lubricate and keep the engine cool. Without properly mixed fuel, the mower may overheat.
Burning fuel creates heat, but so does friction, and oil reduces friction inside the cylinder during combustion.
2-stroke oil mix is is used exclusively as an additive to lubricate the fuel system. Lawn mower oil types used in oil changes have an entirely different purpose.
Table of Contents
2-Stroke Fuel Mix Ratio
Most 2 stroke small engines, such as those found on lawn mowers, and trimmers, require an oil to fuel mix ratio of 40 parts fuel to 1 part oil.
Some small engines, like those on old honda mowers, require a 50 to 1 gas oil mixture, so check manufacturer specs before mixing. This gas oil mix chart shows how much oil to add to the gas.
Too much or too little oil will cause performance issues, so getting the right fuel to oil mixture is extremely important.
For more information about push mower oil types visit the push mower oil page.
Fuel Mix Chart For 2-Stroke Small Engines
|Mix Ratio||Gas Volume||2-Cycle Oil|
|Imperial Fluid Ounces|
|32 To 1||1 gal.||4 oz.|
|40 To 1||1 gal.||3.2 oz.|
|50 To 1||1 gal.||2.6 oz.|
|Metric Fluid Milliliters|
|32 To 1||1 liter||31.25 ml|
|40 To 1||1 liter||25 ml|
|50 To 1||1 liter||20 ml|
Do 4-Cycle Small Engines need mixed gas oil?
4-cycle small engines do not need oil added to the gas, they have an oil reservoir to hold the oil. This is because they have a built-in oiling system to provide lubrication and cooling.
Do not mix oil into the gas of 4-cycle engines unless the manufacturer recommends it.
Is My Small Engine 2 Stroke or 4?
The easiest way to tell if a small engine is a 2 stroke or 4 stroke is by looking for an oil reservoir on the engine.
If present, it will have a filler tube and possibly other markings telling you that's where the oil goes.
All small engines require oil, either in the oil reservoir or mixed with gas, so remember that oil reservoirs are on 4-stroke engines and no oil reservoir means 2-stroke engine.
Only add oil to the gas of 2-stroke engines.
Pre-Mixed 2 cycle Gas
Pre-mixed 2 cycle gas is available at most hardware stores. A gas stabilizing agent is typically added to ready mixed gas to give it a longer shelf life.
The downside to buying ready mixed gas is that it tends to be more expensive than mixing gas and oil yourself.
Additionally, mixing gas and oil yourself allows you to control the octane and ethanol levels of the gas.
Mixing it yourself is often cheaper than buying pre-mixed gas.
Gas/Oil Mix Suggestions
- Use a clean container to store mixed gas
- Write the mix ratio on the side of the container
- Mix and store gas outdoors in a well ventilated area
- Use 2 cycle oil, regular motor oils contain additives
- Mix only what you will need for one season
Common gas oil mix related questions
- Which ratio has more oil? (40 or 50 to 1)
A 40 to 1 gas oil mixture contains more oil than a 50 to 1 mixture when the total volume is the same.
- Is 2-stroke and 2-cycle the same thing?
Yes, both terms refer to the number of piston strokes per complete combustion cycle, they mean the same thing.
- How long can 2 stroke gas be kept?
2-stroke oil has a shelf life of 5 years if unopened and 2 years once unsealed.
After mixing 2-stroke oil with gas, the gas can be safely stored for 2–3 months before it begins to separate and degrade.