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Chainsaw Gas Mix Ratio. Tips From a Professional

There are many different types of chainsaws on the market. Some chainsaws are gas-powered. Others draw their power from batteries or cable connected to a mains outlet. If you own a gas chainsaw, you know that most types need a gas-oil mixture. This chainsaw gas mix ratio is the proportion of gas and oil mixed and used to power a chainsaw. Using the right mix of gas and oil increases the efficiency and durability of your chainsaw.

Chainsaw gas mix ratio

Many older chainsaw models require a 32:1 or 30:1 mix. Most newer models require a ratio of 40:1 (3.2 ounces of two-cycle engine oil per gallon of gas) or 50:1 (2.6 ounces of oil per gallon of gas). In most cases, the 40:1 ratio is recommended because it protects my engine more and increases the longevity of my chainsaws.

This article further examines different gas-powered models and discusses gas mix ratios for your chainsaw and other light machines. I will also explain what happens if you add too much oil in the mix and if it is better to run lean or rich.

What is a 50 to 1 mixture?

A 50 to 1 mixture is obtained by mixing 1 part of engine oil for every 50 equal gas parts.

To get a 50:1 mix ratio, add 2.6 ounces of oil for every gallon of gasoline. Therefore, 12.8 ounces of oil is required for five gallons of gasoline. You can use a calculator to ensure that you get the correct ratio. Alternatively, you can purchase premixed gas products, especially to avoid worrying about these calculations. I also recommend using non-ethanol gasoline because it will help you avoid the risk of damaging your chainsaw.

Does 40 to 1 have more oil than 50 to 1?

Many people often get confused with the math surrounding the oil-gas ratio mix and wonder which ratio has more oil than the other. Though the difference between the 40:1 and 50:1 mix ratio is relatively small, the latter has less oil.

In 40:1, there is one part of oil for every 40 equal parts of gas. On the other hand, in a 50:1 mix ratio, there is one part of oil for every 50 parts of gas. This means that for every 5 gallons of gasoline, 12.8 U.S fluid ounces of oil is used in the 50:1 mix ratio. 16 fluid ounces of oil will be used in the 40:1 ratio for the same amount of gas. With this, you can see that the 40:1 mix ratio offers a greater amount of oil. More oil means more lubrication for your engine.

What is the best 2 stroke mix ratio?

Most of the gas chainsaws on the market have 2-stroke engines. For 2-stoke engines, the gas-oil mix ratios are important as they determine the level of engine lubrication and the number of emissions they produce.

Older 2-stroke chainsaws brands recommended higher levels of oil in the gas mix. They used mixed ratios such as 16:1, 30:1, and 32:1. As technology has evolved, semi-synthetic or synthetic oils came on the market with improved lubrication. As a result, less oil is required to get these engines lubricated. This has led to a general reduction in the levels of oil density recommended by 2-stroke engine manufacturers.

Today, the 50:1 and 40:1 ratios are most often advised by manufacturers. However, both options have their advantages and disadvantages, some of which are as follows. I always recommend checking your brand and model’s correct oil gas ratio.

● 50 to 1 Mix Ratio

50 to 1 gas oil ratio is the most popular ratio among manufacturers of 2-stroke gas power tools, like a chainsaw. The key concern for manufacturers is to choose a gas oil mix ratio that is environmentally friendly, and at the same time, can lubricate their engines properly.

The 50:1 ratio is the sweet spot that produces fewer emissions and, at the same time, gives good lubrication for the engine, especially when synthetic oil is used. On the downside, 50:1 fuel has lower viscosity which may lead to greater gas consumption

● 40 to 1 Mix Ratio

The 40 to 1 oil gas mix has relatively more oil than the 50:1 ratio. This provides more lubrication for the machine’s gas engine and less friction, reducing the risk of wear. It is the ratio that is used mostly for older gas engines. On the flip side, this ratio creates a greater amount of residue and gives off more emissions.

Generally, I recommend a 40:1 mix for your chainsaw if you can not find the correct ratio. Its greater level of lubrication means greater longevity for your engine as the risk of scoring internal parts due to friction is reduced. But if you can find the correct ratio for your machine, this is what you should follow.

How Do You Mix a 40 to 1 Ratio?

Mixing a 40:1 ratio is really easy. You need one part of oil for every 40 parts of gas. Here are the three simple steps to follow when preparing a gallon of fuel for your machine with the 40:1 gas-oil mix ratio:

  • Step 1. Use the correct gas: Get a gallon of ethanol-free gasoline. 89 should be the minimum octane rating in order not to damage or cause overheating to the engine
  • Step 2: Oil: Get 3.2 ounces of engine oil. Be sure to use premium two-cycle oil for this.
  • Step 3. Mix: Pour all the engine oil into the gasoline and give it a good shake. Your fuel is ready for use!.

What Happens If You Mix Too Much Oil in a 2 Stroke

Some people might be tempted to add more oil to their mix to better protect the internal parts of their chainsaw gas engine from the effects of friction. This may indeed help, but too much also has a negative impact. More carbon will build upon the pistons when too much oil is used in a 2-stroke engine.

Over time, such chainsaws can produce excessive smoke and eventually develop fouled or ruined spark plugs. In the long run, excessive oil application might lead to power issues and engine failure, among other problems.

Today’s oils are generally of high quality and can adequately lubricate your engine at the recommended ratio. It is, therefore, advisable to stick with the recommended proportions or add only slightly more oil.

To be fair, it may be argued that having to frequently clean out or replace spark plugs as a consequence of adding excess oil is a far more cost-effective option than having to replace pistons, bearings, or whole engines ruined by excessive metal-to-metal friction.

Is It Better to Run Lean Or Rich?

The argument over running rich or lean is about how much oil should be allowed in the engine combustion chamber in proportion to air. While neither running lean nor running rich can be said to be perfectly desirable, it may be argued that the negative consequences of going lean far outweigh those of running rich. Going rich may cause pollution and waste, and running lean increases your engine’s chance of damage.

The carburetor mixes the gas with air and supplies this to the combustion chamber. When there is a disproportionate amount of air compared to fuel in the combustion chamber, the machine is said to be running lean.

When the amount of fuel in the chamber is disproportionately higher than that of air, the engine is said to be running rich. The ideal mix of fuel and air in the engine is 15 measures of air to 1 part gas. Air moisture and temperature levels play a role here. In hotter conditions, more fuel is generally required to cool the engine.

● Chainsaw Running rich

The major advantage of running rich is that more fuel is available in the combustion to keep the engine temperature within healthy limits. In addition, the predominant presence of air in the combustion chamber causes the engine to heat faster. 

On the flip side, running rich causes fuel waste as some of it will not be used and will have to be ejected from the engine via the exhaust as spooge and smoke. In addition, rich engines often give off large amounts of black smoke, which negatively affects the environment. Also, spark plugs can be fouled as a consequence of increased carbon buildups.

● Chainsaw Running Lean

Running lean has some advantages, such as higher gas efficiency as less of it is left unburnt. On the downside, however, running lean means less fuel moves into the combustion chamber, which means the engine is hotter most of the time.

Engine failure and overheating may affect engines running lean more easily. Under very hot conditions, there is even a real risk that the engine will melt or fail to start. Some internal parts, such as the piston, may also be affected by this overheating when running lean.