Hi Mark.

I have resently learned the hard way..
I used 3 centistoke oil at 5% mix, and this was five months old, stored in a garage. But my turbine has to get some new bearings now, due to this fuel....
So I would not recommend using this fuel, just to be safe.
Ultraviolet rays and the mix itself, destroys the lube- capability of the oil, over time. It will be darker, but even a slight difference in colour, is a NO! So you will have to have fresh fuel to compare whith anyway.
Turbineoils are not made for mixing whith other liquids in the first place.
But I have never heard of others than me, having problems whith "old" fuel.


Gudmund