Good advice lownslo, and Yes, this is fun
Moderation is the key though. I run 5% nitro, 17% oil in all my glow engines, 20% of that oil% being castor. Too much castor gummed and carboned up my engines and they ran like crap. I used to add a couple of ounces of castor to every gallon of fuel years ago but got away from it. Everyone runs and flies their engines differently though. That scenario just didn't work for
me .
I've run 5% in the OS 1.60, Moki 1.35, MVVS .40, Rossi .45 ad infinitum. I also don't need every last blessed rpm out of any of those engines to fly my plane though. The needle tweakers and infinitely unhappy engine owners are the ones that seem to get in trouble. As far as four strokes, again, seek GOOD advice from fellow flyers or the manufacturer. We have factory representation for YS right here if I'm not mistaken? When I was using the older YS 1.20's I ran a 20/20 mix exclusively and it was fine. 20% oil and 20% nitro. This was awhile ago so again, find out what's happening now for your particular situation and go have some fun_bob