Oil in exhaust pipe

Carbon has formed in the return oil line from the turbo to the turbo oil pump. ( large diameter pipe) Disassemble the oil sump and return pipe and remove carbon. The carbon seal was located at the connection of the pipe to oil pump. Just did it for the second time ( interval 4 years and 140 hours ) After the cleaning the turbo works fine again and no leakage anymore. See the Rotax instructional video