I bought 2 packets (44.3mL) of Saber™ Professional Synthetic 100:1 Pre-Mix 2-Cycle Oil (ATP) from Amsoil this year. It’s a synthetic 2-stroke oil and you mix it at a 100:1 ratio for any equipment that requires 40:1. Sounds scary doesn’t it. The synthetic oil lets you mix it much leaner than regular 2-stroke oil. The packet says you can run it in a richer mix as well without plug or spark arrestor fouling so it is more forgiving about the fuel mix.
The only 2-stroke, air cooled piece of equipment I use is an old weed eater which calls for a 40:1 ratio. Last year I ran about 4L of mixed fuel through the machine.
My biggest problem is getting the right mix amount measured from a 1/2 quart bottle of oil. There are syringes and fancy graduated cylinders you can buy to help with that but they are slow and time consuming. Then after using 100ml of oil I have to store the rest in my shed for a very low consumption piece of equipment – that means it is going to sit there for a long time. At my current fuel consumption rate it will take 5 years to use up 500mL of oil @ 40:1.
Most manufacturers suggest oil shelf life is about 2-3 years if kept sealed, out of the sun and within a regulated temperature. These are all conditions my shed doesn’t provide.
Mixing a batch of gas is easy with these packets. Just open a packet, squeeze it into the gas can — just like a tube of toothpaste, roll the package from the back to the front to get the most oil out — and then fill up the can with 4L of fuel. 4L of fuel gives me a ~90:1 ratio which is easier to measure at the gas station pump and verify on the side of the gas can instead of 4.43L. I’ve read there is a buffer and you can go leaner than 100:1 but I choose to error on the side of caution with a slightly richer mixture. You are aiming for something between 4 and 4.5L.
Synthetics are labelled a “greener” 2-stroke since they use a leaner mix. The theory is that you burn less oil but still lubricate the equipment the same amount. 2-strokes get their lubrication oil only from the fuel/oil mixture unlike 4-strokes that have a separate oil sump.
I strongly recommend you adjust your carburetor so that you are sure it isn’t running lean with this new fuel mixture. I do this at the start of each season – only takes a few minutes. Running a 2-cycle engine in a lean condition will eventually destroy the engine no matter which oil you mix in.
I could hear mine making the “four cycling” sound at idle which means it’s a bit rich. The idle to high speed had way less hesitation without any carburetor adjustments which I was impressed with. I was also noticed that there was a lot less smoke from this oil on startup when the engine is still cold which is when the old oil would smoke the most until it got up to operating temperature.