I have a 4*60 and have used a couple of different engines on it. I started out with a K&B .65 sportster. It was brand new and was easy to get running after I fixed all of the leaks it had. I was not impressed with the power from it. It gets better every time I run it as it is finally breaking in. It took about a gallon of fuel. I had a well broken in Super tiger that I tried on it. That is one sweet engine. It has power to spare on this plane. A friend convinced me that he needed it worse than me so I sold it to him. I then put a used TT 61 GP on it. This is the best engine yet. It ran flawlessly right from the start. The air bleed carb had been replaced with a perry carb by whoever had it before I got it. That is why I think it runs so strong. I don't think that there is any thing wrong with the air bleed setup and it is easy to adjust. My engine had the perry already on it and it was already set up. I traded a royal 25 for it. Just use whatever you have and go have fun.

Rick