GMC/Powerbase 800w 2 stroke Generator Fuel Mix

I purchased one of these from Bunnings about 4-5 years ago, for $145, ran it once for about and hour, and put it under the bench. Bought it because it was cheap for the farm! (I Have a Honda 2000i also)

I am now selling it along with my old caravan, but cant find the manuals, so am at a loss with the fuel mix.

I started at 25:1 (to be safe), and it smokes significantly when under load. Went to 50:1 and it still smokes to some degree, although not visibly so except in bright light.

I am surprised at how quiet it is thought, and it seems to have a ton of guts, and runs very well under heavy load.

I even tested it with a $89 Microwave from Woollies, and it run that on low and medium power settings along with all the 240v lights in the van, plus a 150w floodlamp.

I'm not sure I would use it on anything "voltage sensitive" though. It does hunt a fair bit under medium load. (around 300w load)

Does anyone know the correct fuel mix. I accept possibly that all 2 strokes will smoke to some degree, but I have been spoilt by the Honda's.