Have just spent a couple of weeks struggling with 2 strimmers and a chainsaw that wouldn't start or run properly. Discovered pretty much by accident that the petrol bought from Alas in Perello was the problem. Tried Repsol petrol from the next garage and all is well. Used the same oil in both mixes and even went baqck to try the Alas juice again and the problem re-appeared. Alas petrol is blueish in colour and the Repsol is orange-ish. Another chainsaw and a little 2 stroke generator seem to run fine on either.
Might solve someone else's problem.

Have stored petrol and 2 stroke mix in plastic bottles for a few years now without any problems but perish the thought if that petrol wont start a 2 stroke.What the hell would it do to a normal car engine

Bought a couple of plastic jerries in eurasia about 6 yrs ago - use them to store petrol for the genny - hope their okay.

How old was the Alas Petrol? Old petrol loses octanes by evaporation and then will cause problems. The older the petrol is, the less potent it is. I had this problem some years ago with vehicles that had stood for a while. Putting fresh pretrol in always solved the problem. Maybe this is the cause?