So I emailed the company about this fuel back in December and here is what they had to say about the ratio. I've gone with just using the 50:1 mix in my 40:1 ice auger.
Thank you for contacting us! First I like tell you that the FRT-oil included in the Aspen2 gasoline meets the requirements of ISO-L-EGB and JASO-FB. The oil is synthetic, it has a very high quality and a very low ash content compared to ordinary oil and in addition it is biodegradable.
The full answer is off course that you have two options:
1) If you choose to run on Aspen2 you should know that we have been selling Aspen alkylate gasoline for almost 30 years and today we do it in some 25 countries. We have never got a complaint from someone running Aspen2 in a machine specified for 40:1 who has completed the complaint by showing evidence, that is a damaged machine. Never, in many years, on all markets (Aspen is market leaders in many markets in Europe).
2) If you still want to keep to the recommendation of the machine manufacturer you can do it in two ways:
a) Use Aspen2 fuel and add additional oil up to the by the machine manufacturer recommended mixture. Use synthetic oil of high quality. Within shortly Aspens 2-stroke oil will be sold in your area in separate packages
b) Use Aspen4 fuel and add additional oil up to the by the machine manufacturer recommended mixture. Use synthetic oil of high quality. Within shortly Aspens 2-stroke oil will be sold in your area in separate packages.
Please find below a table showing how to mix if you choose to do that:
Desired oil mix Percentage oil Additional to Aspen2 per liter fuel Additional to Aspen4 per liter fuel
1:25 4 0'2 dl 0,4 dl
1:33 3 0,1 dl 0,3 dl
1:40 2,5 0,05 dl 0,25 dl
1:50 2 0 0,2 dl
Best regards
Jürgen Granstedt
Lantmännen Aspen AB