ok thanks for the suggestions, ive been useing duraglo 5 fuel, not sure on the oil content with out looking, maybe i do need to enlarge the exit holes a bit, didnt want to cut the cowl up to much if possible as it looks really good..... but would definatly prefer an engine that keeps running as dead sticks are not my favourite way of landing, the cowel has the standard opening at the front, (ita a seagull extra 300s) and ive cut a large circle where where the head sticks out and cut around the exhaust at the bottom/side. looking at it it prob does need some more off it. thanks.