Given most chainsaws typically use a mixture of oil and gas, understanding the two’s proper ratio is vital to ensure the tool’s optimal performance. Besides providing efficient and optimal performance, proper fuel mixture guarantees you get a trouble-free performance and contributes to prolonging the chainsaw’s service life.
Step 1: Read Your Manual
Every chainsaw comes with a manual that should give you all the information you need to know about it, including the proper oil and gas mixture ratio. Therefore, before anything else, you have to read the manual keenly.
The manual should clarify whether the chainsaw uses the older 30:1 ratio or the two now popular mix ratios, the 40:1 and 50:1. Also, by reading the manual, you know the specific fuel and oil types the manufacturer recommends for optimal performance.
Step 2: Use the Right Container
Once you figure out the manufacturer’s recommendations and direction from the manual, the next step is to choose a suitable container for mixing. It is essential to make sure you never do the mixing directly in the fuel tank.
It would be best to get a UL (Underwriters Laboratories) or FM (Factory Mutual) approved container. The FM or UL-approved safety cans are designed to meet high safety standards, they keep the fuel stable, are spill and leak-proof, and their superior strength allows them to withstand more pressure.
Additionally, the container you choose should be clean and dry with no foreign materials inside, and it ought to have a larger capacity than the volume of the gas and oil you want to mix.
Step 3: Before Fueling
Before you can add fuel to your chainsaw, there are a few essential things you need to do. The key among them is making sure that the fuel cap is clean. By cleaning the fuel cap, you can ensure no foreign substances like dirt will fall into the fuel later when you close the tank.
Another thing to do before fueling the chainsaw is to determine the exact oil and fuel type to use. While some manufacturers make this clear in the manual, if you are still not sure, always use mid-grade unleaded gasoline and make sure it has an octane rating of at least 89. When it comes to the oil, any premium one meant for the 2-cycle engine on a chainsaw should be good enough.
Step 4: Mix Properly
The next step is perhaps the most crucial one, and it entails doing the actual mixing. Here, the most vital thing you need to do is get the ratio right. Most modern chainsaws require either a 40:1 or 50:1 gas and oil mix ratio. The mix charts below should make it clear the quantity of each fluid will need.
40:1 Mix Chart
Oil (fluid ounces)
3.2 fl. oz.
6.4 fl. oz.
9.6 fl. oz.
12.8 fl. oz.
16 fl. oz.
50:1 Mix Chart
Oil (fluid ounces)
2.6 fl. oz.
5.12 fl. oz.
7.68 fl. oz.
10.24 fl. oz.
10.24 fl. oz.
Note: Besides getting the ratios correctly, you also need to do the actual mixing properly. When mixing, always make sure you add the oil first and then the gasoline. Never start with gasoline.
Step 5: Shake Things Up and the Fuel the Chainsaw
With the quantities figured out, you should now pour the premeasured oil in the container and the gasoline. Next, close the container tightly to prevent leakages and shake it aggressively to mix the two fluids properly.
Once the fuel is mixed well, you can add it to the chainsaw. However, if you have not already opened the tank, you should carefully do it to release any tank pressure. You can then add the fuel to the tank but make sure you do it in a room with proper ventilation and in case of some spillage, avoid starting the chainsaws immediately after re-fuelling as this can be dangerous.
Step 6: Storing Gas & Oil Mixtures
It is always best to mix just enough fuel to last you a few days. If using the chainsaws is a one-off thing for you, mix the exact quantity you think you need for the job at hand. However, in case you have any leftover fuel, you have to store it properly.
When storing the remaining fuel, always drain it into an airtight container with a good seal and add a stabilizer to keep it in good shape. Also, it is better not to store it for more than a month, and before using the stored fuel, always give it a thorough shake.
Proper oil and gas mixture is vital to ensure your chainsaw’s efficiency and to keep it in good shape for a long time. The good news is that most manufacturers provide clear directions on the ratios to use, and you just have to read the manual. With this and out step by step guide above to direct you, it should now be easy to figure out the perfect mixture for your chainsaw.