It could be burned castor also. The patch was reddish brown and cleaned off very easily. Its not due to a lean run in though, I kept it thoroughly rich, slobberingly rich in fact

I ran the engine today again. It now seems to have a lot more power. But also a lot more compression. During the rebuild I had to take the rocker assembly off to take the head off. While re-assembling, I just put it back in, I havent moved anything. Thats is why the much higher compression now as compared to before concerns me. Couldnt verify it though coz first time my glow driver had discharged and second time my starter battery discharged to the point I could stop the starter chuck rotating with my hand. With the cowl fitted, I cant put my finger over the carb to choke it. The alternative method of closing the exhaust to choke it cant be done with me both holding the airplane and applying the starter. I will try tomorrow with a friend and my lead acid battery is charging as we speak

Ameyam