Ok, I'd rather see a pic, but I can gamble on $13 for a glow plug adapter...now of the 2 engines the Robin (Fuji) is a NB-16S dont know what that means but thats what it says,, it is the older weedwaker and has a Walbro Far East solid plastic carb (honest),,,the Echo (Kioritz corp) is a GT-200Ce with a Walbro WA 143 one of these I probably need as a weedwaker, which would you use for rc?...I have no problem changing out the rings if they are still available...the throttle body is tiny on both of them, maybe 10 mm eyeballing it,,there are some other serial numbers, but I didnt see where that would help,,if any of this tells you what cc the engines are (i'm guessing 16 and or 20cc how much weight would the plane need to be and what size prop would I need to build a spad trainer to fly?...thanks...Rog