Eric: I’ve been lagging on adding to our Life 101 series, where we document some basic skills that aren’t readily taught anywhere these days. Today’s lesson is properly mixing two stroke oil and fuel.
I needed some fresh mix for my Husqvarna 450 chainsaw to cut down a tree in our backyard. Premix simply means that the oil is already added to the gasoline. It is a simple ratio, and can be measured any number of ways. I prefer to use a purpose built cup to do so, as it makes the task quick and painless.
I also prefer a very high quality oil, not some cheap big box offering. Two stroke engines run at high rpm, and I prefer to protect my investment as much as possible. I use Super M in my CR125, and have wonderful results in longevity despite living near the peak powerband around 11,500 rpm every time I am on the bike. This is especially true in the desert environment.
My chainsaw isn’t much different than my dirt bike, it runs a peak 9000 rpm. I prefer a 32:1 fuel to oil mix, as the additional protection over 40:1 or 50:1 is worth the pennies in additional oil while offering zero downside in performance in my experience. Here we simply find our selected ratio, and add oil to the selected fuel volume.
A closer look at the graduations.
One thing is common every time you put oil in a container, you get a ton of material that adheres to the walls of the measuring device. Once I pour the oil into the fuel, I add a few ounces of fuel to “wash” the oil out, and add it back to the fuel container. That way you know the measured amount ends up where it needs to be.
Now you are left with a clean mixing cup ready for the next use!
This isn’t an advert for any brand, but I have purchased 91 octane exclusively for everything that runs fuel since 2005. I especially like it for fuel cans, as I feel it lasts longer and slowly “degrades” to lower grades over time. I don’t add stabilizer to my premix, as I don’t like using stale mix. It is just too critical for me. If I have any left over, I will add it to one of my vehicles. (We are talking less than a gallon typically)
Simply watch your fuel purchase to make sure you get the proper volume.
Done! I now have a can for the mower, and one premix for the chainsaw. For my purposes, I feel that fresh premix should be used within 6 months, and fresh fuel 12 months for lawn and garden equipment. You might be surprised how fast these days go by when the equipment is in the shed over winter break!