What brand of is the castor oil? It has to be a certain type of refinement to work as an engine lube. I would bet that the engine would run better with the straight 15% nitro all synthetic oil fuel. Aside from that I’m going to say that you may be running too lean on the high speed needle. I would start over with fresh fuel, adjust the air bleed screw so the the screw covers 1/2 the air bleed hole and the high speed needle 2.5 turns from closed. When closing the high speed needle don’t close it down tight as that will damage the carb. Try to adjust the engine with the airplane upside down. I doubt anything is worn out as it is new, the only thing that could be wrong with it is a bent connecting rod from turning it over with a starter when it has too much fuel in it. Is there any way to remount the engine upright? If there is regardless of how bad it may look I would highly suggest doing so. I’m going to be flying in an aerobatics competition for the next two days but I will try to keep an eye on the thread and reply if I am able. Cell service is spotty at times where I fly.