It’s easy to think that chainsaws just use regular gasoline for fuel, but this is not the case. The vast majority of chainsaws require mixing oil with your gasoline as standard. Running your chainsaw on pure gasoline is not recommended.

Most brands of mixed fuel are pre-mixed, but it’s always best to check the manual for your chainsaw to be sure what type of fuel you need to use with your particular device.

The difference between the two main types of engines (both 2 stroke and 4 stroke) is that a traditional 2 stroke engine requires an oil and gasoline mixture. In contrast, a traditional 4 stroke engine has a seperate tank for the oil.

TABLE OF CONTENTS:

Is a chainsaw 2 stroke or 4 stroke?

A chainsaw is a handheld power tool for cutting wood. It has a rotating chain with teeth that cuts through trees, branches, or even small wooden logs when power is pushed through it.

2-Stroke Chainsaws:

The engine itself has one moving part, the piston. The piston goes up and down in the cylinder (connected to a crankshaft). As it turns, it opens/closes ports in the cylinder for airflow. This flow of air makes sure there is enough oxygen to burn all of the fuel entering into each cycle (piston rising or falling).

Oil is mixed into gas because it helps lubricate everything while making combustion more efficient. The oil also helps keep the inside of the cylinder clean by keeping excess fuel from building up and causing corrosion.

4-Stroke Chainsaws:

Has a separate gas and oil mixture. There is an additional part called the transmission. This is what takes your rotational energy from the crankshaft to the sprocket (to a chain).

It has three components: pump (gets oil out of the tank and mixes it with gas), filter (takes particles out of oil before mixing), and carburetor (injects correct ratio of gas+oil into cylinders).

2-stroke chainsaws run on pre-mixed gasoline/2-cycle engine oil; 4 stroke chains run on straight, unleaded gasoline. 2-stroke engines are more fuel-efficient than 4-strokes, but 4-strokes usually last longer.

There is not much to the operation of a chainsaw; it tends to be simple if well taken care of. There are many factors that can affect how it runs, though.

For example, too little oil will cause your engine to seize up and then break; too much oil will mean that combustion is less efficient (more unburnt gas), leaving behind excess carbon in the engine, which will make it run hotter, possibly seizing.

If you mix the wrong amount of oil with gasoline, you get either too lean or too rich (=, not enough/too much air).

Most commonly, people misuse their chainsaws by not mixing enough 2-cycle engine oil. When this happens, the lack of lubrication will cause your gas chainsaw to seize up after running for a while.

If this happens, it is recommended that you drain all excess gasoline from the fuel tank and let it sit overnight so that the majority of the gasoline evaporates away.

Then mix in the correct amount of 2-cycle engine oil before trying to start it again. It would be better to drain out some excess gas next time, but do not use too little, or you risk seizing up your engine again.

What kind of gas does a chainsaw use?

A chainsaw uses regular unleaded gas but it needs to be mixed with the right oil. Most chainsaws use pre-mixed gasoline-oil. Oil is mixed in with the gas to lubricate the engine and prevent fouling.

Chainsaws that take regular gasoline can also be started on a mixture of gas and oil but require more preparation before use. It is recommended that gasoline-oil mix be used because it provides superior performance over straight gasoline.

What kind of oil does a chainsaw use?

A chainsaw uses 2-stroke or 4-stroke oils for lubricating and cooling purposes. Both types are usually compatible with either engine type depending on what brand you have. It’s important to check your owner’s manual if you’re unsure which type you should be using with your particular device.

Oil for a chainsaw can vary in types and brands depending on the equipment itself. Sometimes just an all-purpose oil will work, but other times, a specific kind is needed as per the equipment’s manufacturer.

The easiest option for the right gas/oil mix for your chainsaw is to add a bottle of 50/1 2-stroke engine oil to a gallon of gasoline. Such as this:

How much oil do you mix with gas for chainsaws?

A ratio of 50:1, depending on what type of mixed fuel your particular device takes. It’s recommended to start by using the lower end of the spectrum before moving up to higher volumes if necessary.

Mixed gas varies in ratios because each chainsaw has its specifications that you need to look at for you to figure out how much pre-mix oil and gasoline you should be using for your saw.

You can also check your owner’s manual for this information; it will tell you exactly how much pre-mix oil and gasoline are required for this power tool.

Related article: Do Electric Chainsaws Need Oil?

Can you put too much oil in a chainsaw?

Putting too much oil into your gasoline-powered device is dangerous and can be hazardous to its function. Not only can putting excessive amounts of pre-mix oil make your engine run poorly but there’s also the possibility that it could seize up entirely if left unused long enough.

You should always check your owner’s manual for advice on how much pre-mix gas and oil are required for whatever brand you have, just in case, but 50:1 gas/oil mix ratios are usually safe for most types of equipment.

What happens if you put too much oil in a 2-stroke?

The gas/oil mixture is responsible for lubricating and cooling various parts within the machine to function properly. Suppose the oil content goes above what is recommended for your device.

If you put too much oil in 2-stroke, it will reduce the power output of the chainsaw. In that case, performance will suffer because there won’t be enough properly mixed air to enable proper combustion through either electronic ignition or spark plug.

If you do not put oil in your chainsaw, it will overheat, resulting in serious damage if left untreated. With no way to cool down, the chain may lose its cutting edge quickly while also wearing away at other equipment by scratching or becoming stuck on something hard that it’s being used on.

Putting too much oil in a chainsaw for either 2-stroke or 4-stroke devices will reduce the power output of the saw and cause it to become too inefficient to function properly.

How do you pre-mix oil and gas?

You must have the correct ratio of gas and oil in order to operate your chainsaw successfully. Some brands of mixed fuel recommend using 1 ounce per gallon, while others only require 1/2 ounce per gallon.

If you use too much oil, then it can cause damage to your engine or, in some cases, stop it from running at all. If you use too little oil, your chainsaw will not be properly lubricated, and overheating can occur.

It’s always best to consult your owner’s manual for the proper information on mixing 2-stroke or 4-stroke gas with any pre-mix oil required for your particular device.

How long can 2 stroke fuel be kept?

Mixed gas can be stored for a few months at the very most. After that time, it needs to be put into use or else discarded because oil and gasoline separate from each other after a while since they’re not chemically bonded together.

Fuel that is mixed together and then kept for an extended period can become stale. You should never keep pre-mix gas for more than a month and always use it within the first few months of mixing it, even if you’re not planning to use your chainsaw right away.

Conclusion

Most chainsaws are powered by a 2 stroke engine which requires a gasoline/oil mix to run efficiently. The correct ratio of gas to oil is vitally important for the correct operation and longevity of your chainsaw.

Pure unleaded gasoline should always be mixed with the recommended oil for your particular chainsaw to keep it healthy and running smoothly.

Author – Richard Forde

Richard is the founder of thewoodcuttersson.com and is crazy about everything to do with axes, hatchets, chainsaws and forestry tools. Much of his free time is spent in the woods or writing articles for his blogs.