RE: ASP .52 4 stroke questions
The motor will run on whatever fuel you use in your other glow engines.
10% is a good compromise between performance and cost. I use 15%
I see people use all synthetic and castor mixtures. I cannot honestly say one is better than the other. There are trade offs.
Here is the Manual for the 61 which looks exactly like your 52 on the out side. There's not really much performance difference in them either.
Jim